Intubation of obese patients in the operating room with or without bag-mask ventilation: study protocol for a randomized multicenter trial (VENT OR NOT)

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Obese patients are at higher risk of complications, especially during intubation. Therefore, the management of general anesthesia is crucial. Regarding intubation, there is no consensus among anesthesiologists between the two strategies: standard sequence intubation (i.e., with bag-mask ventilation between induction and intubation) vs. rapid sequence intubation (i.e., without bag-mask ventilation between induction and intubation) assuming that these patients are at high risk of inhalation and desaturation during apnea. This study aims to compare the incidence of intubation-related complications between these two strategies in severely obese patients undergoing elective surgery. Methods The VENT OR NOT study is a prospective, multicenter, open-label, randomized trial including obese patients with a Body Mass Index ≥ 35 kg/m 2 requiring tracheal intubation before scheduled surgery. We will assess the superiority of the standard sequence intubation (“VENT strategy”) compared with the rapid sequence intubation (“NO VENT strategy”) to prevent intubation-related complications in 702 obese patients. Enrolment started in September 2023 in 13 French academic and non-academic hospitals and is expected to finish in September 2025. The primary outcome is a composite outcome of complications occurring from the induction of general anesthesia up to 10 min after intubation including: oxygen desaturation < 95%, intubation failure on the first attempt, aspiration or regurgitation, and severe hypotension, defined as a systolic blood pressure < 80 mmHg. The VENT OR NOT trial began after Ethics Committee approval has been obtained and is carried out according to the principles of the Declaration of Helsinki and the Good Clinical Practice guidelines. Discussion The VENT OR NOT trial is the first randomized controlled trial designed to investigate whether the “VENT strategy” reduces the risk of intubation-related complications compared with the “NO VENT strategy” for elective surgery. Trial registration: ClinicalTrials.gov (NCT05930678), registered on June 1, 2023. Obesity General anesthesia bag-mask ventilation tracheal intubation intubation-related complications Figures Figure 1 Figure 2 Administrative information Note: The numbers in curly brackets in this protocol refer to SPIRIT checklist item numbers. The order of items was modified to group similar items (see http://www.equator-network.org/reporting-guidelines/spirit-2013-statement-defining-standard-protocol-items-for-clinical-trials/). Title {1} Intubation of obese patients in the operating room with or without bag-mask ventilation: study protocol for a randomized multicenter trial (VENT OR NOT). Trial registration {2a and 2b} ClinicalTrials.gov (NCT05930678), registered on June 1, 2023. Protocol version {3} Version 3.0, January 19, 2024. Funding {4} VENT OR NOT is supported by the French Ministry of Health (Interregional French Clinical Hospital Research Program grant, PHRC-IR 2021 API21/N/010). The Nantes University Hospital promotes this study. Author details {5a} Souhaïl Znaïdi 1 , Romain Deransy 2 , Karim Asehnoune 2,3 , Marguerite Le Penndu 2 , Bertrand Rozec 1 , Guillaume Jumel 2 , Sigismond Lasocki 4 , Anna Cadic-Pelletier 5 , Pierre-Grégoire Guinot 6 , Alexis Duchalais 7 , Cédric Cirenei 8 , Stanislas Abrard 9 , Hélène Beloeil 10 , Camille Fortuit 11 , Jérôme Landrin 12 , Guillaume Porta Bonete 13 , Fanny Defrancq 14 , Morgane Péré 15 , and Mickaël Vourc’h 1,3,* 1 Université de Nantes, CHU Nantes, Pôle Anesthésie-Réanimation, Service d’Anesthésie Réanimation Chirurgie Cardiaque, Hôpital Guillaume et René Laennec, Saint-Herblain 44800, France. 2 Université de Nantes, CHU Nantes, Pôle Anesthésie-Réanimation, Service d’Anesthésie Réanimation Chirurgicale, Hôtel Dieu, Nantes F-44093, France. 3 INSERM CIC 0004 Immunologie et Infectiologie, Université de Nantes, France. 4 Université d’Angers, CHU d’Angers, Département Anesthésie Réanimation, Angers F-49933, France. 5 Anaesthesia, and Intensive Care Unit, Brest Regional University Hospital, Brest, France. 6 Department of Anesthesiology and Intensive Care, Dijon University Hospital, Dijon, France. 7 Service d'Anesthésie, Centre Hospitalier Départemental, La Roche-sur-Yon, France. 8 CHU Lille, Pôle d’Anesthésie-Réanimation, 59000, Lille, France. 9 Department of Anesthesiology and Critical Care Medicine, Hospices Civils de Lyon, Hôpital Edouard Herriot, 69437 Lyon, France. 10 Univ Rennes, CHU Rennes, INSERM, OSS 1242, CIC 1414, Anaesthesia and Intensive Care Department, F-35000 Rennes, France. 11 Service d’Anesthésie, Clinique Mutualiste de l’Estuaire, Saint-Nazaire France. 12 Service d’Anesthésie, Centre Hospitalier de Saint-Nazaire, Saint-Nazaire France. 13 Anaesthesia and Intensive Care Unit, Toulouse University Hospital, Toulouse, France. 14 Anaesthesia Unit, Valenciennes Public Hospital, Valenciennes, France. 15 Plateforme de Méthodologie et Biostatistique, CHU Nantes, Nantes, France. *Corresponding author Name and contact information for the trial sponsor {5b} French Ministry of Health 14 avenue Duquesne, 75350 Paris, France +33 1 40 56 60 00 Role of sponsor {5c} The sponsor is responsible for research sponsorship and funding. Introduction Background and rationale {6a} The obesity rate has increased worldwide over the years (23% in Europe and 42.5% in the United States of America) [ 1 , 2 ]. Obesity is a public health issue considering that 20% of the population has a body mass index (BMI) > 30 kg/m 2 . Obese patients undergoing general anesthesia are at a higher risk of complications (severe hypoxemia, hypotension, or cardiac arrest), especially during intubation [ 3 , 4 ]. Obesity decreases the volume of the lungs, mainly the functional residual capacity (i.e., reduction by 69% in patients with a BMI of 40 kg/m 2 in the supine position) [ 5 , 6 ]. This reduction is even more pronounced after the induction of general anesthesia, which exposes patients to a higher risk of hypoxemia, cardiac arrest, and increased postoperative morbidity and mortality. To reduce these risks, many aspects of intubation sequences have been assessed, such as preoxygenation strategy and intubation devices [ 7 – 12 ]. However, the rate of intubation-related complications remains high [ 3 , 4 ]. To further optimize the safety of general anesthesia in obese patients, our study focuses on the role of manual bag-mask ventilation during the apneic intubation time. In this population, two intubation strategies are classically discussed: rapid sequence intubation and standard sequence intubation. In both strategies, the patient stops breathing (i.e., apneic time) after general anesthesia induction and neuromuscular blocker administration. In the standard sequence intubation, the anesthesiologist will proceed with bag-mask ventilation during apnea to avoid reducing the oxygen reserves. At the opposite, in the rapid sequence intubation, the anesthesiologist will not proceed with the bag-mask ventilation during apnea. As a result, the patient may have already drawn in the oxygen reserve when the intubation begins. Conversely, the rapid sequence intubation is often preferred in obese patients who have a higher probability of difficult bag-mask ventilation assuming that bag-mask ventilation increases the risk of aspiration/regurgitation [ 13 ]. However, recent studies did not identify BMI as an independent predictive factor for difficult bag-mask ventilation, [ 14 ] and suggested that obese patients without gastroesophageal reflux are not at a higher risk of inhalation [ 15 , 16 ]. Interestingly, in a pilot trial on 44 obese patients, the standard sequence compared with rapid sequence was reported to reduce oxygen desaturation without increasing the risk of aspiration/regurgitation [ 17 ]. Therefore, we designed a randomized controlled trial comparing the incidence of intubation-related complications between these two strategies in patients with class 2 or higher obesity (BMI ≥ 35 kg/m 2 ). Objectives {7} The main objective is to assess whether bag-mask ventilation during apnea in obese patients reduces the incidence of a composite intubation-related complication score. As secondary objectives, we will compare oxygenation during intubation, incidence of intubation-related complications, respiratory parameters during surgery, and postoperative outcomes between the two intubation strategies. Trial design {8} The VENT OR NOT study is a prospective, multicenter, open-label, randomized trial including class II or higher obese patients (i.e., BMI ≥ 35 kg/m 2 according to the World Health Organization) who require tracheal intubation before scheduled surgery. As detailed above, two intubation strategies are daily used in the operating room: the rapid sequence intubation without bag-mask ventilation during apnea (further referred as “NO VENT” strategy) and the standard sequence intubation with bag-mask ventilation during apnea (further referred as “VENT” strategy). We will assess the superiority of the VENT compared with the NO VENT strategy in preventing intubation-related complications. This study follows the international recommendations for interventional trials. The randomization sequence is computer-generated and stratified at the 13 participating centers (see the SPIRIT checklist in Additional File 1 ). Methods: participants, interventions, and outcomes Study setting {9} This study is conducted in 13 academic and non-academic centers in France (in alphabetic order): Angers: Université d’Angers, CHU d’Angers, Département Anesthésie Réanimation, Angers F-49933, France. Brest: Anesthesia and intensive care unit, Brest Regional University Hospital, Brest, France. Dijon: Department of Anesthesiology and Intensive Care, Dijon University Hospital, Dijon, France. La Roche-sur-Yon: Service d'Anesthésie, Centre Hospitalier Départemental, La Roche-sur-Yon, France. Lille: CHU Lille, Pôle d’Anesthésie-Réanimation, 59000, Lille, France. Lyon: Department of Anesthesiology and Critical Care Medicine, Hospices Civils de Lyon, Hospital Edouard Herriot, 69437 Lyon, France. Nantes: Université de Nantes, CHU Nantes, Pôle Anesthésie-Réanimation, Service d’Anesthésie Réanimation Chirurgie Cardiaque, Hôpital Guillaume et René Laennec, Saint-Herblain 44800, France. Nantes: Université de Nantes, CHU Nantes, Pôle Anesthésie-Réanimation, Service d’Anesthésie Réanimation Chirurgicale, Hôtel Dieu, Nantes F-44093, France. Rennes: Univ Rennes, CHU Rennes, INSERM, OSS 1242, CIC 1414, Anesthesia and Intensive Care Department, F-35000 Rennes, France. Saint-Nazaire: Service d’Anesthésie, Clinique Mutualiste de l’Estuaire, Saint-Nazaire France. Saint-Nazaire: Service d’Anesthésie, Centre Hospitalier de Saint-Nazaire, Saint-Nazaire France. Toulouse: Anesthesia and intensive care unit, Toulouse University Hospital, Toulouse, France. Valenciennes: Anesthesia Unit, Valenciennes Public Hospital, Valenciennes, France. Eligibility criteria {10} The present study includes patients with obesity class II or higher who require general anesthesia for scheduled surgery or endoscopy. Patients are screened and informed during anesthesia consultations. Written consent is then collected after a minimum 4-hour reflection period. Patients cannot be included in another interventional study dealing with ventilation or intubation, which interferes with the primary outcome. Inclusion criteria : Class II or higher obese patient according to the World Health Organization classification (i.e., BMI 35 kg/m 2 and over) Requiring general anesthesia with intubation for a scheduled surgery or endoscopy Aged 18 years old and older Who provided written informed consent Exclusion criteria : Oxygen saturation below 90% in ambient air Urgent surgery (within 24 hours) Cardio-thoracic surgery Patient with predictive criteria of impossible bag-mask ventilation (i.e., history of radiotherapy in cervical area) [ 14 ] Contraindication to bag-mask ventilation during apnea (i.e., intestinal obstruction, non-fasting patient, symptomatic gastroesophageal reflux) Preoxygenation with high-flow therapy Intubation without neuromuscular blocker Awake intubation under spontaneous ventilation Pregnant or breastfeeding women Patient under conservatorship (tutorship, guardianship) Lack of social protection Participation to another study about preoxygenation, ventilation or intubation and interfering with the primary outcome A patient cannot be included twice in the present study for two different general anesthesia. Who will provide informed consent? {26a} The principal investigators (PI) or their assigned delegates obtain written informed consent from the participants. Additional consent provisions for collection and use of participant data and biological specimens {26b} Not applicable. There is no collection of data or biological specimens for ancillary studies. Interventions Explanation for the choice of comparators {6b} There is currently an evidence gap to recommend the VENT or the NO VENT strategy for intubation in obese patients. As a result, there is an equipoise among anesthesiologists, and the two intubation strategies are daily used in the operating room [ 17 – 20 ]. Intervention description {11a} Obese class II or higher patients are recruited during the preoperative anesthetic consultation. After obtaining written informed consent, the patients are randomized between the NO VENT or VENT strategies (see Fig. 1 ). The study starts when the patient enters the operating room. In both arms, general anesthesia begins with a 4-minute preoxygenation in a 25° head-up position. Preoxygenation is performed with a bag-mask tightly applied to the patient’s face to avoid leaks, with non-invasive bi-level positive airway pressure (BiPAP), 100% fraction of inspired oxygen. The expiratory positive airway pressure (PEEP) is set at 5 cmH 2 O and inspiratory positive airway pressure (PIP) between 10 and 20 cmH 2 O, indicating pressure support between 5 and 15 cmH 2 O for a targeted tidal volume of 6 to 8 mL/kg of ideal body weight. The choice of this preoxygenation method for all participants is based on current data reporting the superiority of non-invasive ventilation over other preoxygenation methods in obese patients [ 7 – 10 ] and hypoxemic patients [ 25 ]. At the end of the preoxygenation, the aim is to obtain a fraction of expired oxygen (FeO 2 ) ≥ 90%. The clinician can decide to prolong the preoxygenation for more than 4 minutes if FeO 2 cannot be reached. If the patient cannot tolerate BiPAP preoxygenation, an alternative device can be used (facemask without positive airway pressure, high-flow oxygen therapy with nasal cannulas, etc.). This is recorded as a protocol deviation because preoxygenation quality can alter the primary outcome. In the NO VENT group, participants receive hypnotics (with or without opioids) and neuromuscular blockers with a short onset (i.e., rocuronium or suxamethonium). The anesthesiologist does not ventilate the patient with a bag-mask during the onset of anesthesia, and proceeds to intubation as soon as neuromuscular blocking is effective. However, the anesthesiologist can ventilate the patient in case of desaturation below 95% or for a safety reason. In the VENT group, participants receive hypnotics (with or without opioids) and neuromuscular blocker of either short or long onset (i.e., atracurium or cisatracurium). The anesthesiologist ventilates the patient with a bag-mask during apnea up to the onset of anesthesia and neuromuscular blocking and proceeds to intubation. During bag-mask ventilation, the ventilator is set with a tidal volume between 6 and 8 mL/kg of ideal body weight, expiratory positive airway pressure of 5 cmH 2 O. Peak inspiratory pressure should not exceed 20 cmH 2 O. For patients with difficult mechanical ventilation via a face mask, manual bag-mask ventilation is allowed [ 26 , 27 ]. The use of any airway patency maneuver such as the Guedel pattern airway, jaw-thrust, or head tilt-chin lift maneuvers is allowed (non-exhaustive list). Monitoring neuromuscular blocking is encouraged by the study protocol, as well as the use of video laryngoscopes for the first intubation attempt. In both groups, bag-mask ventilation is possible at any time in cases of oxygen desaturation below 95%, or to ensure patient safety. During general anesthesia, mechanical ventilation settings follow international guidelines [ 18 , 19 , 28 ]. Notably, the tidal volume is set between 6 and 8 mL/kg of ideal body weight, with an expiratory positive airway pressure of at least 5 cmH 2 O, and the plateau pressure must not exceed 30 cmH 2 O. Criteria for discontinuing or modifying allocated interventions {11b} In case of an emergency (i.e., desaturation, impossible bag-valve ventilation), the patient’s oxygenation is prioritized. In this case, the attending physician is free to use any oxygenation or intubation device to ensure oxygenation in both arms to secure the patient’s airway. Strategies to improve adherence to interventions {11c} As VENT or NO VENT strategies are used daily in the operating room, we expect high adherence to the protocol. Before starting inclusion, the habits of each center regarding airway management in obese patients were analyzed to ensure that the study design will not disrupt local protocols. To ensure exhaustivity of data collection, a specific sheet was created to record all key events of the intubation procedure. Relevant concomitant care permitted or prohibited during the trial {11d} The nature of hypnotic agents and opioids remains at the discretion of attending physicians. The use of neuromuscular blockers in both arms is mandatory. In the NO VENT group, the patient can only receive neuromuscular blockers of short onset because bag-mask ventilation is not allowed during apnea. Provisions for post-trial care {30} The Nantes University Hospital purchased insurance to take financial responsibility for post-trial care in cases of serious adverse events. Outcomes {12} Primary outcome The primary outcome is a composite criterion: the occurrence (yes or no) of at least one intubation-related complication (Fig. 2) among the following: Oxygen desaturation under 95% Failure of tracheal intubation at the first attempt Aspiration/regurgitation Hypotension, defined as a systolic blood pressure < 80 mmHg (regardless of the use of catecholamines). For the primary outcome, these complications are recorded from the induction of general anesthesia up to 10 min after intubation. The percentage of patients presenting with the primary outcome will be compared between the two groups (see the statistical section for further information on the analysis). Secondary outcomes 1.Progress of intubation procedure Lowest saturation before the first laryngoscopy Lowest saturation during intubation procedure (from induction up to 10 minutes after intubation, including the rate of desaturation under 95% as one of the components of the primary outcome) Quality of laryngoscopy exposition (Cormack-Lehane Classification System) Intubation difficulties Intubation Difficulty Scale (IDS) including the number of attempts; number of operators; number of alternative techniques; quality of exposure under laryngoscopy; lifting force required; laryngeal pressure maneuvers; vocal cord mobility Failure of the first attempt (component of the primary outcome) Duration of the procedure Rescue bag-mask ventilation because of oxygen desaturation below 95% or to ensure patient’s safety (from induction up to 10 minutes after intubation) Bag-mask ventilation difficulties (in the VENT group or during rescue bag-mask ventilation regardless of the randomization group) defined as: Peak inspiratory pressure over 25 cmH 2 O Multiple uses of oxygen by-pass during bag-mask ventilation Failure to obtain a visible chest expansion, or tidal volume of at least 3 mL/kg of ideal body weight, or a clear capnography curve, or oxygen saturation over 92% [ 26 , 27 ] 2.Intubation-related complications Up to 1 hour after the induction of general anesthesia Oxygen desaturation under 80% and under 90% Severe hypotension, defined as a systolic blood pressure under 80 mmHg with or without catecholamines (component of the primary outcome) Supraventricular or ventricular arrhythmias (atrial fibrillation, ventricular extra beats, ventricular tachycardia, ventricular fibrillation) or bradycardia Cardiac arrest Aspiration/regurgitation (component of the primary outcome) Esophageal intubation Dental injuries Death Allergic reaction 3.Respiratory parameters following intubation During surgery: Need to use a fraction of inspired oxygen over 50% to obtain saturation over 95% Need to use lung recruitment maneuver Plateau pressure at 5, 30 and 60 minutes after intubation After surgery: Length of stay in the post-anesthesia care unit Length of mechanical ventilation postoperatively Need of non-invasive ventilation after extubation Nausea, vomiting 4.Other outcomes : In-hospital length of stay (from randomization) In-hospital mortality Participant timeline {13} SPIRIT figure VENT OR NOT trial schedule. STUDY PERIOD Enrolment Allocation Post-allocation Close-out TIMEPOINT Pre-anesthetic consultation or visit Before general anesthesia induction t 1 t 2 t 3 t 4 Until hospital exit ENROLMENT : Eligibility screen X Informed consent X Allocation X INTERVENTIONS : NO VENT group X VENT group X ASSESSMENTS : Height and weight X Predictive criteria of impossible bag-mask ventilation X X Oxygen saturation in ambient air X X Primary outcome X Oxygen saturation X X X Blood pressure X X X Aspiration/ Regurgitation X X X Failure of tracheal intubation at first attempt X Intubation difficulties X Esophageal intubation X X Dental injuries X X Ventilation difficulties X X Arrhythmias X X X Cardiac arrest X X X Need to use FiO 2 > 50% X X Need of lung recruitment maneuver X X Plateau pressure X X Length of stay in post-anesthesia care unit X Length of MV post-operatively X Need of NIV after extubation X Nausea, vomiting X In-hospital length of stay X Death X X X X X Legend (SPIRIT figure) t1, general anesthesia induction; t2, from induction to 10 min after intubation; t3, during surgery; t4, in the post-anesthesia care unit. NO VENT group, without bag-mask ventilation during the apneic time before intubation (unless necessary following the trial protocol). VENT group, with bag-mask ventilation during the apneic time before intubation MV, mechanical ventilation; NIV, non-invasive ventilation; FiO 2 , fraction of inspired oxygen Sample size {14} In the PREOPTIPOP trial, which included patients with class II or higher obesity, all participants were intubated according to the NO VENT strategy [ 4 ]. In the latter, 36% of the patients presented with at least one intubation-related complication, as defined in the primary outcome in the present study. Using a two-sided test with an alpha risk of 5% and a power of 80%, and adding a 5% attrition rate, 702 patients are needed (i.e., 351 patients in each group with a 1:1 ratio of randomization) to show a 10% reduction in intubation-related complications with the VENT strategy. Recruitment {15} The inclusion and non-inclusion criteria are screened during anesthetic consultation. Clinical research associates (CRAs) and clinicians screen patients and fulfil the screening log. Assignment of interventions: allocation Sequence generation {16a} The clinical research team screens, enrolls and randomizes the participants. Randomization is centralized, web-based, and available 24-hour a day. The allocation list is generated by a statistician. Randomization is stratified according to the type of surgery (bariatric or non-bariatric), and performed using a 1:1 ratio. Concealment mechanism {16b} Randomization is web-based and performed the day of the surgery, independently of the data analyst and the clinician. Randomization is sequentially numbered. Participants are assigned to the VENT or NO VENT group in a 1:1 ratio with variable block size. Implementation {16c} At inclusion, participants are randomly assigned to the VENT or NO VENT group using computer-generated randomization. A CRA transmits the allocated group to anesthesiologist in charge of the patient. Assignment of interventions: Blinding Who will be blinded {17a} Not applicable. The VENT OR NOT study is an open-label trial; participants and investigators are unblinded. Procedure for unblinding if needed {17b} Procedure for unblinding is not applicable. Investigators are aware of treatment allocation because the two intubation strategies clearly differ. Data collection and management Plans for assessment and collection of outcomes {18a} The baseline information of each participant is recovered from the anesthetic consultation. Baseline characteristics are collected, including age, sex, height, weight, ideal body weight, body mass index, type of surgery or endoscopy, comorbidities (cardiorespiratory, otorhinolaryngology, carcinology, smoking status, and sleep apnea), oxygen saturation in ambient air, and predictive criteria for difficult ventilation or intubation (non-exhaustive list). Most of the outcomes are automatically saved in the electronic anesthesia record. A spreadsheet was created to facilitate exhaustive data collection. CRAs subsequently enter all the data on the electronic Case Report Form (eCRF) via their personal online access account. Patients are followed until hospital discharge (see the SPIRIT figure ). Plans to promote participant retention and complete follow-up {18b} As the primary outcome is collected during general anesthesia, few patients will be lost to follow-up. Data management {19} Data are recorded on an eCRF hosted on a dedicated server with controlled access. All modifications, additions, and deletions are recorded. Clinical trial data will be stored for at least 15 years after the end of the trial. Confidentiality {27} To preserve the confidentiality of participants, they are identified using alphanumeric numbers in the eCRF. Plans for collection, laboratory evaluation and storage of biological specimens for genetic or molecular analysis in this trial/future use {33} No biological specimens will be collected. Statistical methods Statistical methods for primary and secondary outcomes {20a} Recruitment will stop when 702 randomized patients will have undergone intubation. Continuous variables will be presented as means and standard deviations (as medians and quartiles, otherwise), and categorical data will be presented as exact numbers and percentages. Analyses will be conducted on the intention-to-treat population, defined as all randomized patients who underwent intubation (primary analysis). Patients in the NO VENT group undergoing bag-mask ventilation without desaturation < 95% will be considered to meet the primary outcome in the primary analysis. Randomized patients who did not undergo intubation (i.e., surgery cancelled for logistic reasons) will not be included in the intention-to-treat analysis. The per-protocol analysis will exclude patients with non-inclusion criteria, protocol deviations, or missing data for the primary outcome. The proportion of intubation-related complications will be compared between groups using a mixed logistic regression model adjusted for stratification criterion (bariatric surgery) as a fixed effect and for center as a random effect. Secondary quantitative endpoints will be compared between the groups using mixed linear regression and secondary binary endpoints using mixed logistic regression. Interim analyses {21b} Two interim analyses are planned for the efficacy of the primary outcome with O’Brien and Fleming’s alpha spending function approach to control for type I error: the first after the inclusion of 234 patients and the second after the inclusion of 468 patients [ 29 ], with respective P-values to determine the efficacy of 0.0002 and 0.012. These interim analyses are also planned to assess safety data, especially the rate of intubation-related complications, which is a point of interest for the Data and Safety Monitoring Board (see the dedicated section). Methods for additional analyses (e.g. subgroup analyses) {20b} As an exploratory analysis, the primary outcome will be compared in several subgroups: bariatric vs. non-bariatric surgery; BMI < 40 kg/ m 2 vs. BMI ≥ 40 kg/m 2 ; oxygen saturation at the end of the preoxygenation period < 97% vs. ≥ 97%; direct laryngoscopy versus video-laryngoscopy as the first intubation device; and depolarizing vs. non-depolarizing neuromuscular blockers. A logistic regression model will be used to compare the primary outcomes between the two groups in the above subgroup analyses. As these are exploratory analyses, no alpha risk adjustment for multiplicity is planned. Methods in analysis to handle protocol non-adherence and any statistical methods to handle missing data {20c} The per-protocol analysis will exclude patients with non-inclusion criteria, protocol deviations, or missing data for the primary outcome (see above). Importantly, patients from the NO VENT group receiving bag-mask ventilation without desaturation under 95% will be included in the per-protocol analysis because their exclusion could heavily bias the results against the VENT group (i.e., this strategy excludes patients likely to present desaturation in the NO VENT group and reduces the percentage of patients meeting the primary outcome). Similarly, patients in the NO VENT group who experienced desaturation under 95% with or without bag-mask ventilation will be included in the per-protocol analysis. Data on the primary outcome should not be missing, as they are collected during general anesthesia in the operating room. However, in the case of missing data, a multiple imputation procedure based on the data at inclusion will be used. Plans to give access to the full protocol, participant-level data and statistical code {31c} The protocol is available on ClinicalTrials.gov since June 1, 2023. The full protocol will be published with the results of the trial. All participant-level data and statistical codes will be made available on a specific request with the authorization of the Nantes University Hospital, the leading investigator and the statistician of the study. Oversight and monitoring Composition of the coordinating center, trial steering committee and Data and Safety Monitoring Board {5d} The coordinating center is Nantes University Hospital. MV is the leading investigator and leads the coordination team composed of clinicians and CRAs. At each participating center, the principal investigator is responsible for ensuring compliance with the study protocol. A specific meeting with all the members of the coordination team was organized before the start of inclusion in each center. The Data and Safety Monitoring Board (DSMB) is composed of Pr. Jean-Michel Constantin (Assistance Publique des Hôpitaux de Paris, France), Pr. Emmanuel Futier (CHU de Clermont-Ferrand, France) and Lionel Velly (Assistance Publique des Hôpitaux de Marseille, France). The DSMB will analyze the safety results (i.e., incidence of intubation-related complications) of the two interim analyses to decide whether the trial should be continued or stopped. Composition of the data monitoring committee, its role and reporting structure {21a} Monitoring follows Good Clinical Practice principles and is performed by the department of the Nantes University Hospital Research Management Unit. A CRA regularly visits each center to control the quality of the recorded data. CRAs can check the anesthetic report. The following data are assessed: written informed consent, flow chart for included and non-included patients, trial progress, and collection of primary and secondary outcomes. CRAs are independent of the trial coordination team to guarantee impartiality in data review. Adverse event reporting and harms {22} Adverse events are collected on the eCRF and reported to the appropriate institutional vigilance system of each center. Frequency and plans for auditing trial conduct {23} The promotion department of the Nantes University Hospital Research Management Unit audits the involved centers. The audit will include a review of source documents and a double check of the primary outcome and all secondary outcomes (i.e., monitoring 100% of the data) for 10% of the patients. Written informed consent will be checked for 100% of the participants. The aim is to ensure the compliance of the trial protocol and the Good Clinical Practice guidelines. Plans for communicating important protocol amendments to relevant parties (e.g. trial participants, ethical committees) {25} Major changes to the trial protocol will be reported by the promoter to the Comité de Protection des Personnes. The amended protocol will be edited, dated, and declared at ClinicalTrials.gov. The consent form will be modified accordingly, if needed. Dissemination plans {31a} The results of this study will be disseminated through presentations at scientific conferences and through publications in peer-reviewed journals. Discussion Obesity is a public health issue because the proportion of people with a BMI over 30 kg/m 2 is increasing. Airway management of obese patients in the operating room is a daily challenge [ 20 , 30 – 32 ]. To date, no randomized controlled trial has compared the VENT and NO VENT strategies in a large sample of obese patients. The NO VENT strategy has both positive and negative aspects. On the one hand, it may reduce the risk of aspiration/regurgitation secondary to gastric insufflation related to bag-mask ventilation, especially in patients with difficult or impossible bag-mask ventilation criteria. On the other hand, because apnea usually occurs quickly after the administration of hypnotics, the patient has already drawn in the oxygen reserve when anesthesia and neuromuscular blocking are deep enough to start intubation. Consequently, hypnotics and neuromuscular blockers are administered over a short period of time to reduce the delay between apnea and intubation. This does not allow titration of hypnotics according to patient consciousness and could therefore increase the risk of hypotension. Similarly, depending on the nature of the intubation sequence (i.e., depth of anesthesia and delay of action of neuromuscular blockers), the quality of glottis exposition could differ, and the rate of first-attempt success can change. Finally, neuromuscular blockers with a fast onset of action present a higher risk of anaphylaxis [ 33 ]. Theoretically, the VENT strategy, including bag-mask ventilation after apnea and before intubation, could maximize the oxygen reserve before intubation. Furthermore, because apnea time is not a limiting parameter in this strategy, progressive titration of hypnotics is possible, thereby reducing the risk of side effects, such as hypotension. Nevertheless, bag-mask ventilation is sometimes difficult or impossible in obese patients, and represents a risk of gastric insufflation. Therefore, this strategy may increase the risk of aspiration/regurgitation. However, a recent large multicenter randomized controlled study demonstrated that, in critically ill patients, who were commonly reported at a very high risk of aspiration/inhalation, bag-mask ventilation did not increase aspiration/regurgitation [ 34 ]. Thus, uncertainty remains regarding the best intubation strategy to be adopted in obese patients worldwide. The choice of the primary outcome may be questionable. It includes components that the VENT strategy could reduce (i.e., desaturation, hypotension, or first-attempt intubation failure), and events that were reported to increase with a VENT strategy (i.e., aspiration/regurgitation). Accordingly, a significant difference between groups (i.e., reduction of desaturation, hypotension, and intubation failure without increasing aspiration/regurgitation) will bring strong results to the field of intubation in obese patients. Each component of the primary outcome will be assessed separately. The threshold of 95% for oxygen desaturation as the primary outcome may be controversial because it does not represent an immediate threat to the patient. However, this threshold is currently admitted to (re) starting bag-mask ventilation to avoid deeper desaturation [ 5 ]. As the lowest saturation during the intubation procedure is also collected, we will be able to judge whether the difference between groups is relevant. Trial status The study protocol was edited in its first version on March 17, 2023. It was published at ClinicalTrials.gov on June 1, 2023 (NCT05930678). Recruitment began on September 2023, and the first patient was included on September 12, 2023. The last version of the protocol is version 3.0, which was edited on January 19, 2024. Most of the study centers have already begun inclusion. A total of 702 patients are expected to be included to complete recruitment before September 2025. Abbreviations BiPAP bi-level positive airway pressure BMI body mass index CRA clinical research associate DSMB Data and Safety Monitoring Board eCRF electronic case report form FiO 2 fraction of inspired oxygen IDS intubation difficulty scale MV mechanical ventilation NIV non-invasive ventilation PEEP expiratory positive airway pressure PI principal investigator PIP inspiratory positive airway pressure Declarations Acknowledgements We thank the patients, physicians, anesthesia nurses, and CRAs of the participating centers for their involvement in this study. Authors’ contributions {31b} MV is the Chief Investigator; he designed the study and obtained funding. MV and MP planned the statistical analyses. MV, RD, KA, BR, SZ and GJ introduced the study protocol to the participating centers. MV and SZ will have full access to the final trial dataset. MV, SZ, RD, KA and BR drafted the manuscript. All authors have read and approved the final manuscript. For the final publication, the authors will be determined according to the proportion of patients included in each center. Funding {4} The VENT OR NOT study is supported by the French Ministry of Health (Interregional French Clinical Hospital Research Program grant PHRC-IR 2021 API21/N/010). The Nantes University Hospital promotes this study. Availability of data and materials {29} The final de-identified trial dataset will be available to all investigators and the research team of all the participating centers. Ethics approval and consent to participate {24} The study protocol was approved by the Ethics Committee CPP Est III on May 31, 2023. The trial is conducted according to the principles of the Declaration of Helsinki and the Good Clinical Practice guidelines. Patients are included after written informed consent. Clinicians ensure information and consent collection. Consent for publication {32} All participants are informed that their anonymized data will be used for publication. Competing interests {28} The authors declare that they have no conflicts of interest. References Products -HE. Stats - Prevalence of Overweight, Obesity, and Extreme Obesity Among Adults Aged 20 and Over: United States, 1960–1962 Through 2017–2018. 2021. https://www.cdc.gov/nchs/data/hestat/obesity-adult-17-18/obesity-adult.htm . Accessed 19 Jun 2024. WHO European Regional Obesity Report. 2022. https://www.who.int/europe/publications/i/item/9789289057738 . Accessed 19 Jun 2024. Yakushiji H, Goto T, Shirasaka W, Hagiwara Y, Watase H, Okamoto H, et al. Associations of obesity with tracheal intubation success on first attempt and adverse events in the emergency department: An analysis of the multicenter prospective observational study in Japan. PLoS ONE. 2018;13:e0195938. Vourc’h M, Baud G, Feuillet F, Blanchard C, Mirallie E, Guitton C, et al. High-flow Nasal Cannulae Versus Non-invasive Ventilation for Preoxygenation of Obese Patients: The PREOPTIPOP Randomized Trial. 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De Jong A, Molinari N, Pouzeratte Y, Verzilli D, Chanques G, Jung B, et al. Difficult intubation in obese patients: incidence, risk factors, and complications in the operating theatre and in intensive care units. Br J Anaesth. 2015;114:297–306. Moon TS, Fox PE, Somasundaram A, Minhajuddin A, Gonzales MX, Pak TJ, et al. The influence of morbid obesity on difficult intubation and difficult mask ventilation. J Anesth. 2019;33:96–102. Brodsky JB, Lemmens HJM, Brock-Utne JG, Vierra M, Saidman LJ. Morbid obesity and tracheal intubation. Anesth Analg. 2002;94:732–6. table of contents. Reddy JI, Cooke PJ, van Schalkwyk JM, Hannam JA, Fitzharris P, Mitchell SJ. Anaphylaxis is more common with rocuronium and succinylcholine than with atracurium. Anesthesiology. 2015;122:39–45. Casey JD, Janz DR, Russell DW, Vonderhaar DJ, Joffe AM, Dischert KM, et al. Bag-Mask Ventilation during Tracheal Intubation of Critically Ill Adults. N Engl J Med. 2019;380:811–21. Supplementary Files AdditionalFile1SPIRITchecklist.docx Informedconsentdocumentation.pdf POINTBYPOINTRESPONSE.docx SPIRITFigure.doc Translationoftheinformedconsentdocumentation.docx VENTORNOTtrialversionwithtrackedchanges.docx WHOTrialRegistrationDataSet.docx Cite Share Download PDF Status: Published Journal Publication published 11 Nov, 2025 Read the published version in Trials → Version 1 posted Reviewers agreed at journal 27 Apr, 2025 Reviewers invited by journal 27 Apr, 2025 Editor assigned by journal 27 Apr, 2025 First submitted to journal 27 Apr, 2025 You are reading this latest preprint version Research Square lets you share your work early, gain feedback from the community, and start making changes to your manuscript prior to peer review in a journal. As a division of Research Square Company, we’re committed to making research communication faster, fairer, and more useful. We do this by developing innovative software and high quality services for the global research community. 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07:02:52","extension":"docx","order_by":12,"title":"","display":"","copyAsset":false,"role":"supplement","size":18627,"visible":true,"origin":"","legend":"","description":"","filename":"WHOTrialRegistrationDataSet.docx","url":"https://assets-eu.researchsquare.com/files/rs-4693821/v1/b944fe7ea04793939d2e69c1.docx"}],"financialInterests":"","formattedTitle":"\u003cp\u003eIntubation of obese patients in the operating room with or without bag-mask ventilation: study protocol for a randomized multicenter trial (VENT OR NOT)\u003c/p\u003e","fulltext":[{"header":"Administrative information","content":"\u003cp\u003eNote: The numbers in curly brackets in this protocol refer to SPIRIT checklist item numbers. The order of items was modified to group similar items (see http://www.equator-network.org/reporting-guidelines/spirit-2013-statement-defining-standard-protocol-items-for-clinical-trials/).\u003c/p\u003e\n\u003ctable border=\"1\" cellspacing=\"0\" cellpadding=\"0\"\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 21.9634%;\"\u003e\n \u003cp\u003e\u003cstrong\u003eTitle {1}\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 78.0366%;\"\u003e\n \u003cp\u003eIntubation of obese patients in the operating room with or without bag-mask ventilation: study protocol for a randomized multicenter trial (VENT OR NOT).\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 21.9634%;\"\u003e\n \u003cp\u003e\u003cstrong\u003eTrial registration {2a and 2b}\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 78.0366%;\"\u003e\n \u003cp\u003eClinicalTrials.gov (NCT05930678), registered on June 1, 2023.\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 21.9634%;\"\u003e\n \u003cp\u003e\u003cstrong\u003eProtocol version {3}\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 78.0366%;\"\u003e\n \u003cp\u003eVersion 3.0, January 19, 2024.\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 21.9634%;\"\u003e\n \u003cp\u003e\u003cstrong\u003eFunding {4}\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 78.0366%;\"\u003e\n \u003cp\u003eVENT OR NOT is supported by the French Ministry of Health (Interregional French Clinical Hospital Research Program\u0026nbsp;grant, PHRC-IR 2021 API21/N/010). The Nantes University Hospital promotes this study.\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 21.9634%;\"\u003e\n \u003cp\u003e\u003cstrong\u003eAuthor details {5a}\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 78.0366%;\"\u003e\n \u003cp\u003eSouha\u0026iuml;l Zna\u0026iuml;di\u003csup\u003e1\u003c/sup\u003e, Romain Deransy\u003csup\u003e2\u003c/sup\u003e, Karim Asehnoune\u003csup\u003e2,3\u003c/sup\u003e, Marguerite Le Penndu\u003csup\u003e2\u003c/sup\u003e, Bertrand Rozec\u003csup\u003e1\u003c/sup\u003e, Guillaume Jumel\u003csup\u003e2\u003c/sup\u003e, Sigismond Lasocki\u003csup\u003e4\u003c/sup\u003e, Anna Cadic-Pelletier\u003csup\u003e5\u003c/sup\u003e, Pierre-Gr\u0026eacute;goire Guinot\u003csup\u003e6\u003c/sup\u003e, Alexis Duchalais\u003csup\u003e7\u003c/sup\u003e, C\u0026eacute;dric Cirenei\u003csup\u003e8\u003c/sup\u003e, Stanislas Abrard\u003csup\u003e9\u003c/sup\u003e, H\u0026eacute;l\u0026egrave;ne Beloeil\u003csup\u003e10\u003c/sup\u003e, Camille Fortuit\u003csup\u003e11\u003c/sup\u003e, J\u0026eacute;r\u0026ocirc;me Landrin\u003csup\u003e12\u003c/sup\u003e, Guillaume Porta Bonete\u003csup\u003e13\u003c/sup\u003e, Fanny Defrancq\u003csup\u003e14\u003c/sup\u003e, Morgane P\u0026eacute;r\u0026eacute;\u003csup\u003e15\u003c/sup\u003e, and Micka\u0026euml;l Vourc\u0026rsquo;h\u003csup\u003e1,3,*\u003c/sup\u003e\u003c/p\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003cp\u003e\u003csup\u003e1\u003c/sup\u003eUniversité de Nantes, CHU Nantes, Pôle Anesthésie-Réanimation, Service d\u0026rsquo;Anesthésie Réanimation Chirurgie Cardiaque, Hôpital Guillaume et Ren\u0026eacute; Laennec, Saint-Herblain 44800, France.\u003c/p\u003e\n \u003cp\u003e\u003csup\u003e2\u003c/sup\u003eUniversité de Nantes, CHU Nantes, Pôle Anesthésie-Réanimation, Service d\u0026rsquo;Anesthésie Réanimation Chirurgicale, Hôtel Dieu, Nantes F-44093, France.\u003c/p\u003e\n \u003cp\u003e\u003csup\u003e3\u003c/sup\u003eINSERM CIC 0004 Immunologie et Infectiologie, Université de Nantes, France.\u003c/p\u003e\n \u003cp\u003e\u003csup\u003e4\u003c/sup\u003eUniversité d\u0026rsquo;Angers, CHU d\u0026rsquo;Angers, Département Anesthésie Réanimation, Angers F-49933, France.\u003c/p\u003e\n \u003cp\u003e\u003csup\u003e5\u003c/sup\u003eAnaesthesia, and Intensive Care Unit, Brest Regional University Hospital, Brest, France.\u003c/p\u003e\n \u003cp\u003e\u003csup\u003e6\u003c/sup\u003eDepartment of Anesthesiology and Intensive Care, Dijon University Hospital, Dijon, France.\u003c/p\u003e\n \u003cp\u003e\u003csup\u003e7\u003c/sup\u003eService d\u0026apos;Anesth\u0026eacute;sie, Centre Hospitalier D\u0026eacute;partemental, La Roche-sur-Yon, France.\u003c/p\u003e\n \u003cp\u003e\u003csup\u003e8\u003c/sup\u003eCHU Lille, P\u0026ocirc;le d\u0026rsquo;Anesth\u0026eacute;sie-R\u0026eacute;animation, 59000, Lille, France.\u003c/p\u003e\n \u003cp\u003e\u003csup\u003e9\u003c/sup\u003eDepartment of Anesthesiology and Critical Care Medicine, Hospices Civils de Lyon, H\u0026ocirc;pital Edouard Herriot, 69437 Lyon, France.\u003c/p\u003e\n \u003cp\u003e\u003csup\u003e10\u003c/sup\u003eUniv Rennes, CHU Rennes, INSERM, OSS 1242, CIC 1414, Anaesthesia and Intensive Care Department, F-35000 Rennes, France.\u003c/p\u003e\n \u003cp\u003e\u003csup\u003e11\u003c/sup\u003eService d\u0026rsquo;Anesth\u0026eacute;sie, Clinique Mutualiste de l\u0026rsquo;Estuaire, Saint-Nazaire France.\u003c/p\u003e\n \u003cp\u003e\u003csup\u003e12\u003c/sup\u003eService d\u0026rsquo;Anesth\u0026eacute;sie, Centre Hospitalier de Saint-Nazaire, Saint-Nazaire France.\u003c/p\u003e\n \u003cp\u003e\u003csup\u003e13\u003c/sup\u003eAnaesthesia and Intensive Care Unit, Toulouse University Hospital, Toulouse, France.\u003c/p\u003e\n \u003cp\u003e\u003csup\u003e14\u003c/sup\u003eAnaesthesia Unit, Valenciennes Public Hospital, Valenciennes, France.\u003c/p\u003e\n \u003cp\u003e\u003csup\u003e15\u003c/sup\u003ePlateforme de M\u0026eacute;thodologie et Biostatistique, CHU Nantes, Nantes, France.\u003c/p\u003e\n \u003cp\u003e*Corresponding author\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 21.9634%;\"\u003e\n \u003cp\u003e\u003cstrong\u003eName and contact information for the trial sponsor {5b}\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 78.0366%;\"\u003e\n \u003cp\u003eFrench Ministry of Health\u003c/p\u003e\n \u003cp\u003e14 avenue Duquesne, 75350 Paris, France\u003c/p\u003e\n \u003cp\u003e+33 1 40 56 60 00\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 21.9634%;\"\u003e\n \u003cp\u003e\u003cstrong\u003eRole of sponsor {5c}\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 78.0366%;\"\u003e\n \u003cp\u003eThe sponsor is responsible for research sponsorship and funding.\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n\u003c/table\u003e"},{"header":"Introduction","content":"\n\u003ch3\u003eBackground and rationale {6a}\u003c/h3\u003e\n\u003cp\u003eThe obesity rate has increased worldwide over the years (23% in Europe and 42.5% in the United States of America) [\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e, \u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e]. Obesity is a public health issue considering that 20% of the population has a body mass index (BMI)\u0026thinsp;\u0026gt;\u0026thinsp;30 kg/m\u003csup\u003e2\u003c/sup\u003e. Obese patients undergoing general anesthesia are at a higher risk of complications (severe hypoxemia, hypotension, or cardiac arrest), especially during intubation [\u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e, \u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e]. Obesity decreases the volume of the lungs, mainly the functional residual capacity (i.e., reduction by 69% in patients with a BMI of 40 kg/m\u003csup\u003e2\u003c/sup\u003e in the supine position) [\u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e, \u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e]. This reduction is even more pronounced after the induction of general anesthesia, which exposes patients to a higher risk of hypoxemia, cardiac arrest, and increased postoperative morbidity and mortality.\u003c/p\u003e \u003cp\u003eTo reduce these risks, many aspects of intubation sequences have been assessed, such as preoxygenation strategy and intubation devices [\u003cspan additionalcitationids=\"CR8 CR9 CR10 CR11\" citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e12\u003c/span\u003e]. However, the rate of intubation-related complications remains high [\u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e, \u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e]. To further optimize the safety of general anesthesia in obese patients, our study focuses on the role of manual bag-mask ventilation during the apneic intubation time.\u003c/p\u003e \u003cp\u003eIn this population, two intubation strategies are classically discussed: rapid sequence intubation and standard sequence intubation. In both strategies, the patient stops breathing (i.e., apneic time) after general anesthesia induction and neuromuscular blocker administration. In the standard sequence intubation, the anesthesiologist will proceed with bag-mask ventilation during apnea to avoid reducing the oxygen reserves. At the opposite, in the rapid sequence intubation, the anesthesiologist will not proceed with the bag-mask ventilation during apnea. As a result, the patient may have already drawn in the oxygen reserve when the intubation begins. Conversely, the rapid sequence intubation is often preferred in obese patients who have a higher probability of difficult bag-mask ventilation assuming that bag-mask ventilation increases the risk of aspiration/regurgitation [\u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e13\u003c/span\u003e]. However, recent studies did not identify BMI as an independent predictive factor for difficult bag-mask ventilation, [\u003cspan citationid=\"CR14\" class=\"CitationRef\"\u003e14\u003c/span\u003e] and suggested that obese patients without gastroesophageal reflux are not at a higher risk of inhalation [\u003cspan citationid=\"CR15\" class=\"CitationRef\"\u003e15\u003c/span\u003e, \u003cspan citationid=\"CR16\" class=\"CitationRef\"\u003e16\u003c/span\u003e]. Interestingly, in a pilot trial on 44 obese patients, the standard sequence compared with rapid sequence was reported to reduce oxygen desaturation without increasing the risk of aspiration/regurgitation [\u003cspan citationid=\"CR17\" class=\"CitationRef\"\u003e17\u003c/span\u003e]. Therefore, we designed a randomized controlled trial comparing the incidence of intubation-related complications between these two strategies in patients with class 2 or higher obesity (BMI\u0026thinsp;\u0026ge;\u0026thinsp;35 kg/m\u003csup\u003e2\u003c/sup\u003e).\u003c/p\u003e\n\u003ch3\u003eObjectives {7}\u003c/h3\u003e\n\u003cp\u003eThe main objective is to assess whether bag-mask ventilation during apnea in obese patients reduces the incidence of a composite intubation-related complication score. As secondary objectives, we will compare oxygenation during intubation, incidence of intubation-related complications, respiratory parameters during surgery, and postoperative outcomes between the two intubation strategies.\u003c/p\u003e \u003cdiv id=\"Sec3\" class=\"Section2\"\u003e \u003ch2\u003eTrial design {8}\u003c/h2\u003e \u003cp\u003eThe VENT OR NOT study is a prospective, multicenter, open-label, randomized trial including class II or higher obese patients (i.e., BMI\u0026thinsp;\u0026ge;\u0026thinsp;35 kg/m\u003csup\u003e2\u003c/sup\u003e according to the World Health Organization) who require tracheal intubation before scheduled surgery.\u003c/p\u003e \u003cp\u003eAs detailed above, two intubation strategies are daily used in the operating room: the rapid sequence intubation without bag-mask ventilation during apnea (further referred as \u0026ldquo;NO VENT\u0026rdquo; strategy) and the standard sequence intubation with bag-mask ventilation during apnea (further referred as \u0026ldquo;VENT\u0026rdquo; strategy).\u003c/p\u003e \u003cp\u003eWe will assess the superiority of the VENT compared with the NO VENT strategy in preventing intubation-related complications. This study follows the international recommendations for interventional trials. The randomization sequence is computer-generated and stratified at the 13 participating centers (see the SPIRIT checklist in \u003cb\u003eAdditional File 1\u003c/b\u003e).\u003c/p\u003e \u003c/div\u003e"},{"header":"Methods: participants, interventions, and outcomes","content":"\u003cdiv id=\"Sec5\" class=\"Section2\"\u003e \u003ch2\u003eStudy setting {9}\u003c/h2\u003e \u003cp\u003eThis study is conducted in 13 academic and non-academic centers in France (in alphabetic order):\u003c/p\u003e \u003cp\u003e\u003cul\u003e\u003cli\u003e\u003cp\u003eAngers: Universit\u0026eacute; d\u0026rsquo;Angers, CHU d\u0026rsquo;Angers, D\u0026eacute;partement Anesth\u0026eacute;sie R\u0026eacute;animation, Angers F-49933, France.\u003c/p\u003e\u003c/li\u003e\u003cli\u003e\u003cp\u003eBrest: Anesthesia and intensive care unit, Brest Regional University Hospital, Brest, France.\u003c/p\u003e\u003c/li\u003e\u003cli\u003e\u003cp\u003eDijon: Department of Anesthesiology and Intensive Care, Dijon University Hospital, Dijon, France.\u003c/p\u003e\u003c/li\u003e\u003cli\u003e\u003cp\u003eLa Roche-sur-Yon: Service d'Anesth\u0026eacute;sie, Centre Hospitalier D\u0026eacute;partemental, La Roche-sur-Yon, France.\u003c/p\u003e\u003c/li\u003e\u003cli\u003e\u003cp\u003eLille: CHU Lille, P\u0026ocirc;le d\u0026rsquo;Anesth\u0026eacute;sie-R\u0026eacute;animation, 59000, Lille, France.\u003c/p\u003e\u003c/li\u003e\u003cli\u003e\u003cp\u003e Lyon: Department of Anesthesiology and Critical Care Medicine, Hospices Civils de Lyon, Hospital Edouard Herriot, 69437 Lyon, France.\u003c/p\u003e\u003c/li\u003e\u003cli\u003e\u003cp\u003eNantes: Universit\u0026eacute; de Nantes, CHU Nantes, P\u0026ocirc;le Anesth\u0026eacute;sie-R\u0026eacute;animation, Service d\u0026rsquo;Anesth\u0026eacute;sie R\u0026eacute;animation Chirurgie Cardiaque, H\u0026ocirc;pital Guillaume et Ren\u0026eacute; Laennec, Saint-Herblain 44800, France.\u003c/p\u003e\u003c/li\u003e\u003cli\u003e\u003cp\u003eNantes: Universit\u0026eacute; de Nantes, CHU Nantes, P\u0026ocirc;le Anesth\u0026eacute;sie-R\u0026eacute;animation, Service d\u0026rsquo;Anesth\u0026eacute;sie R\u0026eacute;animation Chirurgicale, H\u0026ocirc;tel Dieu, Nantes F-44093, France.\u003c/p\u003e\u003c/li\u003e\u003cli\u003e\u003cp\u003e Rennes: Univ Rennes, CHU Rennes, INSERM, OSS 1242, CIC 1414, Anesthesia and Intensive Care Department, F-35000 Rennes, France.\u003c/p\u003e\u003c/li\u003e\u003cli\u003e\u003cp\u003eSaint-Nazaire: Service d\u0026rsquo;Anesth\u0026eacute;sie, Clinique Mutualiste de l\u0026rsquo;Estuaire, Saint-Nazaire France.\u003c/p\u003e\u003c/li\u003e\u003cli\u003e\u003cp\u003eSaint-Nazaire: Service d\u0026rsquo;Anesth\u0026eacute;sie, Centre Hospitalier de Saint-Nazaire, Saint-Nazaire France.\u003c/p\u003e\u003c/li\u003e\u003cli\u003e\u003cp\u003eToulouse: Anesthesia and intensive care unit, Toulouse University Hospital, Toulouse, France.\u003c/p\u003e\u003c/li\u003e\u003cli\u003e\u003cp\u003eValenciennes: Anesthesia Unit, Valenciennes Public Hospital, Valenciennes, France.\u003c/p\u003e\u003c/li\u003e\u003c/ul\u003e\u003c/p\u003e \u003c/div\u003e\n\u003ch3\u003eEligibility criteria {10}\u003c/h3\u003e\n\u003cp\u003eThe present study includes patients with obesity class II or higher who require general anesthesia for scheduled surgery or endoscopy. Patients are screened and informed during anesthesia consultations. Written consent is then collected after a minimum 4-hour reflection period.\u003c/p\u003e \u003cp\u003ePatients cannot be included in another interventional study dealing with ventilation or intubation, which interferes with the primary outcome.\u003c/p\u003e \u003cp\u003e \u003cspan type=\"Underline\" class=\"Underline\" name=\"Emphasis\"\u003eInclusion criteria\u003c/span\u003e:\u003c/p\u003e \u003cp\u003e\u003cul\u003e\u003cli\u003e\u003cp\u003eClass II or higher obese patient according to the World Health Organization classification (i.e., BMI 35 kg/m\u003csup\u003e2\u003c/sup\u003e and over)\u003c/p\u003e\u003c/li\u003e\u003cli\u003e\u003cp\u003eRequiring general anesthesia with intubation for a scheduled surgery or endoscopy\u003c/p\u003e\u003c/li\u003e\u003cli\u003e\u003cp\u003eAged 18 years old and older\u003c/p\u003e\u003c/li\u003e\u003cli\u003e\u003cp\u003e Who provided written informed consent\u003c/p\u003e\u003c/li\u003e\u003c/ul\u003e\u003c/p\u003e \u003cp\u003e \u003cspan type=\"Underline\" class=\"Underline\" name=\"Emphasis\"\u003eExclusion criteria\u003c/span\u003e:\u003c/p\u003e \u003cp\u003e \u003cul\u003e \u003cli\u003e \u003cp\u003eOxygen saturation below 90% in ambient air\u003c/p\u003e \u003c/li\u003e \u003cli\u003e \u003cp\u003eUrgent surgery (within 24 hours)\u003c/p\u003e \u003c/li\u003e \u003cli\u003e \u003cp\u003eCardio-thoracic surgery\u003c/p\u003e \u003c/li\u003e \u003cli\u003e \u003cp\u003ePatient with predictive criteria of impossible bag-mask ventilation (i.e., history of radiotherapy in cervical area) [\u003cspan citationid=\"CR14\" class=\"CitationRef\"\u003e14\u003c/span\u003e]\u003c/p\u003e \u003c/li\u003e \u003cli\u003e \u003cp\u003eContraindication to bag-mask ventilation during apnea (i.e., intestinal obstruction, non-fasting patient, symptomatic gastroesophageal reflux)\u003c/p\u003e \u003c/li\u003e \u003cli\u003e \u003cp\u003ePreoxygenation with high-flow therapy\u003c/p\u003e \u003c/li\u003e \u003cli\u003e \u003cp\u003eIntubation without neuromuscular blocker\u003c/p\u003e \u003c/li\u003e \u003cli\u003e \u003cp\u003eAwake intubation under spontaneous ventilation\u003c/p\u003e \u003c/li\u003e \u003cli\u003e \u003cp\u003ePregnant or breastfeeding women\u003c/p\u003e \u003c/li\u003e \u003cli\u003e \u003cp\u003ePatient under conservatorship (tutorship, guardianship)\u003c/p\u003e \u003c/li\u003e \u003cli\u003e \u003cp\u003eLack of social protection\u003c/p\u003e \u003c/li\u003e \u003cli\u003e \u003cp\u003eParticipation to another study about preoxygenation, ventilation or intubation and interfering with the primary outcome\u003c/p\u003e \u003c/li\u003e \u003c/ul\u003e \u003c/p\u003e \u003cp\u003eA patient cannot be included twice in the present study for two different general anesthesia.\u003c/p\u003e\n\u003ch3\u003eWho will provide informed consent? {26a}\u003c/h3\u003e\n\u003cp\u003eThe principal investigators (PI) or their assigned delegates obtain written informed consent from the participants.\u003c/p\u003e \u003cdiv id=\"Sec8\" class=\"Section2\"\u003e \u003ch2\u003eAdditional consent provisions for collection and use of participant data and biological specimens {26b}\u003c/h2\u003e \u003cp\u003eNot applicable. There is no collection of data or biological specimens for ancillary studies.\u003c/p\u003e \u003c/div\u003e\n\u003ch3\u003eInterventions\u003c/h3\u003e\n\u003cdiv id=\"Sec10\" class=\"Section2\"\u003e \u003ch2\u003eExplanation for the choice of comparators {6b}\u003c/h2\u003e \u003cp\u003eThere is currently an evidence gap to recommend the VENT or the NO VENT strategy for intubation in obese patients. As a result, there is an equipoise among anesthesiologists, and the two intubation strategies are daily used in the operating room [\u003cspan additionalcitationids=\"CR18 CR19\" citationid=\"CR17\" class=\"CitationRef\"\u003e17\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR20\" class=\"CitationRef\"\u003e20\u003c/span\u003e].\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec11\" class=\"Section2\"\u003e \u003ch2\u003eIntervention description {11a}\u003c/h2\u003e \u003cp\u003eObese class II or higher patients are recruited during the preoperative anesthetic consultation. After obtaining written informed consent, the patients are randomized between the NO VENT or VENT strategies (see \u003cb\u003eFig.\u0026nbsp;1\u003c/b\u003e).\u003c/p\u003e \u003cp\u003eThe study starts when the patient enters the operating room. In both arms, general anesthesia begins with a 4-minute preoxygenation in a 25\u0026deg; head-up position. Preoxygenation is performed with a bag-mask tightly applied to the patient\u0026rsquo;s face to avoid leaks, with non-invasive bi-level positive airway pressure (BiPAP), 100% fraction of inspired oxygen. The expiratory positive airway pressure (PEEP) is set at 5 cmH\u003csub\u003e2\u003c/sub\u003eO and inspiratory positive airway pressure (PIP) between 10 and 20 cmH\u003csub\u003e2\u003c/sub\u003eO, indicating pressure support between 5 and 15 cmH\u003csub\u003e2\u003c/sub\u003eO for a targeted tidal volume of 6 to 8 mL/kg of ideal body weight. The choice of this preoxygenation method for all participants is based on current data reporting the superiority of non-invasive ventilation over other preoxygenation methods in obese patients [\u003cspan additionalcitationids=\"CR8 CR9\" citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e] and hypoxemic patients [\u003cspan citationid=\"CR25\" class=\"CitationRef\"\u003e25\u003c/span\u003e]. At the end of the preoxygenation, the aim is to obtain a fraction of expired oxygen (FeO\u003csub\u003e2\u003c/sub\u003e)\u0026thinsp;\u0026ge;\u0026thinsp;90%. The clinician can decide to prolong the preoxygenation for more than 4 minutes if FeO\u003csub\u003e2\u003c/sub\u003e cannot be reached. If the patient cannot tolerate BiPAP preoxygenation, an alternative device can be used (facemask without positive airway pressure, high-flow oxygen therapy with nasal cannulas, etc.). This is recorded as a protocol deviation because preoxygenation quality can alter the primary outcome.\u003c/p\u003e \u003cp\u003e\u003cul\u003e\u003cli\u003e\u003cp\u003e In the NO VENT group, participants receive hypnotics (with or without opioids) and neuromuscular blockers with a short onset (i.e., rocuronium or suxamethonium). The anesthesiologist does not ventilate the patient with a bag-mask during the onset of anesthesia, and proceeds to intubation as soon as neuromuscular blocking is effective. However, the anesthesiologist can ventilate the patient in case of desaturation below 95% or for a safety reason.\u003c/p\u003e\u003c/li\u003e\u003cli\u003e\u003cp\u003e In the VENT group, participants receive hypnotics (with or without opioids) and neuromuscular blocker of either short or long onset (i.e., atracurium or cisatracurium). The anesthesiologist ventilates the patient with a bag-mask during apnea up to the onset of anesthesia and neuromuscular blocking and proceeds to intubation. During bag-mask ventilation, the ventilator is set with a tidal volume between 6 and 8 mL/kg of ideal body weight, expiratory positive airway pressure of 5 cmH\u003csub\u003e2\u003c/sub\u003eO. Peak inspiratory pressure should not exceed 20 cmH\u003csub\u003e2\u003c/sub\u003eO. For patients with difficult mechanical ventilation via a face mask, manual bag-mask ventilation is allowed [\u003cspan citationid=\"CR26\" class=\"CitationRef\"\u003e26\u003c/span\u003e, \u003cspan citationid=\"CR27\" class=\"CitationRef\"\u003e27\u003c/span\u003e]. The use of any airway patency maneuver such as the Guedel pattern airway, jaw-thrust, or head tilt-chin lift maneuvers is allowed (non-exhaustive list).\u003c/p\u003e\u003c/li\u003e\u003c/ul\u003e\u003c/p\u003e \u003cp\u003eMonitoring neuromuscular blocking is encouraged by the study protocol, as well as the use of video laryngoscopes for the first intubation attempt. In both groups, bag-mask ventilation is possible at any time in cases of oxygen desaturation below 95%, or to ensure patient safety.\u003c/p\u003e \u003cp\u003eDuring general anesthesia, mechanical ventilation settings follow international guidelines [\u003cspan citationid=\"CR18\" class=\"CitationRef\"\u003e18\u003c/span\u003e, \u003cspan citationid=\"CR19\" class=\"CitationRef\"\u003e19\u003c/span\u003e, \u003cspan citationid=\"CR28\" class=\"CitationRef\"\u003e28\u003c/span\u003e]. Notably, the tidal volume is set between 6 and 8 mL/kg of ideal body weight, with an expiratory positive airway pressure of at least 5 cmH\u003csub\u003e2\u003c/sub\u003eO, and the plateau pressure must not exceed 30 cmH\u003csub\u003e2\u003c/sub\u003eO.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec12\" class=\"Section2\"\u003e \u003ch2\u003eCriteria for discontinuing or modifying allocated interventions {11b}\u003c/h2\u003e \u003cp\u003eIn case of an emergency (i.e., desaturation, impossible bag-valve ventilation), the patient\u0026rsquo;s oxygenation is prioritized. In this case, the attending physician is free to use any oxygenation or intubation device to ensure oxygenation in both arms to secure the patient\u0026rsquo;s airway.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec13\" class=\"Section2\"\u003e \u003ch2\u003eStrategies to improve adherence to interventions {11c}\u003c/h2\u003e \u003cp\u003eAs VENT or NO VENT strategies are used daily in the operating room, we expect high adherence to the protocol. Before starting inclusion, the habits of each center regarding airway management in obese patients were analyzed to ensure that the study design will not disrupt local protocols. To ensure exhaustivity of data collection, a specific sheet was created to record all key events of the intubation procedure.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec14\" class=\"Section2\"\u003e \u003ch2\u003eRelevant concomitant care permitted or prohibited during the trial {11d}\u003c/h2\u003e \u003cp\u003eThe nature of hypnotic agents and opioids remains at the discretion of attending physicians. The use of neuromuscular blockers in both arms is mandatory. In the NO VENT group, the patient can only receive neuromuscular blockers of short onset because bag-mask ventilation is not allowed during apnea.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec15\" class=\"Section2\"\u003e \u003ch2\u003eProvisions for post-trial care {30}\u003c/h2\u003e \u003cp\u003eThe Nantes University Hospital purchased insurance to take financial responsibility for post-trial care in cases of serious adverse events.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec16\" class=\"Section2\"\u003e \u003ch2\u003eOutcomes {12}\u003c/h2\u003e \u003cdiv id=\"Sec17\" class=\"Section3\"\u003e \u003ch2\u003ePrimary outcome\u003c/h2\u003e \u003cp\u003eThe primary outcome is a composite criterion: the occurrence (yes or no) of at least one intubation-related complication (Fig.\u0026nbsp;2) among the following:\u003c/p\u003e \u003cp\u003e \u003cul\u003e \u003cli\u003e \u003cp\u003eOxygen desaturation under 95%\u003c/p\u003e \u003c/li\u003e \u003cli\u003e \u003cp\u003eFailure of tracheal intubation at the first attempt\u003c/p\u003e \u003c/li\u003e \u003cli\u003e \u003cp\u003eAspiration/regurgitation\u003c/p\u003e \u003c/li\u003e \u003cli\u003e \u003cp\u003eHypotension, defined as a systolic blood pressure\u0026thinsp;\u0026lt;\u0026thinsp;80 mmHg (regardless of the use of catecholamines).\u003c/p\u003e \u003c/li\u003e \u003c/ul\u003e \u003c/p\u003e \u003cp\u003eFor the primary outcome, these complications are recorded from the induction of general anesthesia up to 10 min after intubation.\u003c/p\u003e \u003cp\u003eThe percentage of patients presenting with the primary outcome will be compared between the two groups (see the statistical section for further information on the analysis).\u003c/p\u003e \u003c/div\u003e \u003c/div\u003e \u003cdiv id=\"Sec18\" class=\"Section2\"\u003e \u003ch2\u003eSecondary outcomes\u003c/h2\u003e \u003cp\u003e \u003cspan type=\"Underline\" class=\"Underline\" name=\"Emphasis\"\u003e1.Progress of intubation procedure\u003c/span\u003e \u003c/p\u003e \u003cp\u003e \u003cul\u003e \u003cli\u003e \u003cp\u003eLowest saturation before the first laryngoscopy\u003c/p\u003e \u003c/li\u003e \u003cli\u003e \u003cp\u003eLowest saturation during intubation procedure (from induction up to 10 minutes after intubation, including the rate of desaturation under 95% as one of the components of the primary outcome)\u003c/p\u003e \u003c/li\u003e \u003cli\u003e \u003cp\u003eQuality of laryngoscopy exposition (Cormack-Lehane Classification System)\u003c/p\u003e \u003c/li\u003e \u003cli\u003e \u003cp\u003eIntubation difficulties\u003c/p\u003e \u003cp\u003e \u003cul\u003e \u003cli\u003e \u003cp\u003eIntubation Difficulty Scale (IDS) including the number of attempts; number of operators; number of alternative techniques; quality of exposure under laryngoscopy; lifting force required; laryngeal pressure maneuvers; vocal cord mobility\u003c/p\u003e \u003c/li\u003e \u003cli\u003e \u003cp\u003eFailure of the first attempt (component of the primary outcome)\u003c/p\u003e \u003c/li\u003e \u003cli\u003e \u003cp\u003eDuration of the procedure\u003c/p\u003e \u003c/li\u003e \u003c/ul\u003e \u003c/p\u003e \u003c/li\u003e \u003cli\u003e \u003cp\u003eRescue bag-mask ventilation because of oxygen desaturation below 95% or to ensure patient\u0026rsquo;s safety (from induction up to 10 minutes after intubation)\u003c/p\u003e \u003c/li\u003e \u003cli\u003e \u003cp\u003eBag-mask ventilation difficulties (in the VENT group or during rescue bag-mask ventilation regardless of the randomization group) defined as:\u003c/p\u003e \u003cp\u003e \u003cul\u003e \u003cli\u003e \u003cp\u003ePeak inspiratory pressure over 25 cmH\u003csub\u003e2\u003c/sub\u003eO\u003c/p\u003e \u003c/li\u003e \u003cli\u003e \u003cp\u003eMultiple uses of oxygen by-pass during bag-mask ventilation\u003c/p\u003e \u003c/li\u003e \u003cli\u003e \u003cp\u003eFailure to obtain a visible chest expansion, or tidal volume of at least 3 mL/kg of ideal body weight, or a clear capnography curve, or oxygen saturation over 92% [\u003cspan citationid=\"CR26\" class=\"CitationRef\"\u003e26\u003c/span\u003e, \u003cspan citationid=\"CR27\" class=\"CitationRef\"\u003e27\u003c/span\u003e]\u003c/p\u003e \u003c/li\u003e \u003c/ul\u003e \u003c/p\u003e \u003c/li\u003e \u003c/ul\u003e \u003c/p\u003e \u003cp\u003e \u003cspan type=\"Underline\" class=\"Underline\" name=\"Emphasis\"\u003e2.Intubation-related complications\u003c/span\u003e \u003c/p\u003e \u003cp\u003e \u003cul\u003e \u003cli\u003e \u003cp\u003eUp to 1 hour after the induction of general anesthesia\u003c/p\u003e \u003cp\u003e \u003cul\u003e \u003cli\u003e \u003cp\u003eOxygen desaturation under 80% and under 90%\u003c/p\u003e \u003c/li\u003e \u003cli\u003e \u003cp\u003eSevere hypotension, defined as a systolic blood pressure under 80 mmHg with or without catecholamines (component of the primary outcome)\u003c/p\u003e \u003c/li\u003e \u003cli\u003e \u003cp\u003eSupraventricular or ventricular arrhythmias (atrial fibrillation, ventricular extra beats, ventricular tachycardia, ventricular fibrillation) or bradycardia\u003c/p\u003e \u003c/li\u003e \u003cli\u003e \u003cp\u003eCardiac arrest\u003c/p\u003e \u003c/li\u003e \u003c/ul\u003e \u003c/p\u003e \u003c/li\u003e \u003cli\u003e \u003cp\u003eAspiration/regurgitation (component of the primary outcome)\u003c/p\u003e \u003c/li\u003e \u003cli\u003e \u003cp\u003eEsophageal intubation\u003c/p\u003e \u003c/li\u003e \u003cli\u003e \u003cp\u003eDental injuries\u003c/p\u003e \u003c/li\u003e \u003cli\u003e \u003cp\u003eDeath\u003c/p\u003e \u003c/li\u003e \u003cli\u003e \u003cp\u003eAllergic reaction\u003c/p\u003e \u003c/li\u003e \u003c/ul\u003e \u003c/p\u003e \u003cp\u003e \u003cspan type=\"Underline\" class=\"Underline\" name=\"Emphasis\"\u003e3.Respiratory parameters following intubation\u003c/span\u003e \u003c/p\u003e \u003cp\u003e \u003cul\u003e \u003cli\u003e \u003cp\u003eDuring surgery:\u003c/p\u003e \u003cp\u003e \u003cul\u003e \u003cli\u003e \u003cp\u003eNeed to use a fraction of inspired oxygen over 50% to obtain saturation over 95%\u003c/p\u003e \u003c/li\u003e \u003cli\u003e \u003cp\u003eNeed to use lung recruitment maneuver\u003c/p\u003e \u003c/li\u003e \u003cli\u003e \u003cp\u003ePlateau pressure at 5, 30 and 60 minutes after intubation\u003c/p\u003e \u003c/li\u003e \u003c/ul\u003e \u003c/p\u003e \u003c/li\u003e \u003cli\u003e \u003cp\u003eAfter surgery:\u003c/p\u003e \u003cp\u003e \u003cul\u003e \u003cli\u003e \u003cp\u003eLength of stay in the post-anesthesia care unit\u003c/p\u003e \u003c/li\u003e \u003cli\u003e \u003cp\u003eLength of mechanical ventilation postoperatively\u003c/p\u003e \u003c/li\u003e \u003cli\u003e \u003cp\u003eNeed of non-invasive ventilation after extubation\u003c/p\u003e \u003c/li\u003e \u003cli\u003e \u003cp\u003eNausea, vomiting\u003c/p\u003e \u003c/li\u003e \u003c/ul\u003e \u003c/p\u003e \u003c/li\u003e \u003c/ul\u003e \u003c/p\u003e \u003cp\u003e \u003cspan type=\"Underline\" class=\"Underline\" name=\"Emphasis\"\u003e4.Other outcomes\u003c/span\u003e:\u003c/p\u003e \u003cp\u003e \u003cul\u003e \u003cli\u003e \u003cp\u003eIn-hospital length of stay (from randomization)\u003c/p\u003e \u003c/li\u003e \u003cli\u003e \u003cp\u003eIn-hospital mortality\u003c/p\u003e \u003c/li\u003e \u003c/ul\u003e \u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec19\" class=\"Section2\"\u003e \u003ch2\u003eParticipant timeline {13}\u003c/h2\u003e \u003cp\u003e \u003cspan type=\"BoldUnderline\" class=\"BoldUnderline\" name=\"Emphasis\"\u003eSPIRIT figure\u003c/span\u003e \u003cb\u003eVENT OR NOT trial schedule.\u003c/b\u003e\u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"No\" id=\"Tabb\" border=\"1\"\u003e \u003ccolgroup cols=\"9\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c5\" colnum=\"5\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c6\" colnum=\"6\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c7\" colnum=\"7\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c8\" colnum=\"8\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c9\" colnum=\"9\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/th\u003e \u003cth align=\"left\" colspan=\"8\" nameend=\"c9\" namest=\"c2\"\u003e \u003cp\u003eSTUDY PERIOD\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003eEnrolment\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e \u003cp\u003eAllocation\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colspan=\"5\" nameend=\"c8\" namest=\"c4\"\u003e \u003cp\u003ePost-allocation\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c9\"\u003e \u003cp\u003eClose-out\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e \u003cp\u003eTIMEPOINT\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003e\u003cem\u003ePre-anesthetic consultation or visit\u003c/em\u003e\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e \u003cp\u003eBefore general anesthesia induction\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c4\"\u003e \u003cp\u003e\u003cem\u003et\u003c/em\u003e\u003csub\u003e\u003cem\u003e1\u003c/em\u003e\u003c/sub\u003e\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c5\"\u003e \u003cp\u003e\u003cem\u003et\u003c/em\u003e\u003csub\u003e\u003cem\u003e2\u003c/em\u003e\u003c/sub\u003e\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c6\"\u003e \u003cp\u003e\u003cem\u003et\u003c/em\u003e\u003csub\u003e\u003cem\u003e3\u003c/em\u003e\u003c/sub\u003e\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c7\"\u003e \u003cp\u003e\u003cem\u003et\u003c/em\u003e\u003csub\u003e\u003cem\u003e4\u003c/em\u003e\u003c/sub\u003e\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c8\"\u003e\u0026nbsp;\u003c/th\u003e \u003cth align=\"left\" colname=\"c9\"\u003e \u003cp\u003e\u003cem\u003eUntil hospital exit\u003c/em\u003e\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eENROLMENT\u003c/b\u003e:\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eEligibility screen\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eX\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eInformed consent\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eX\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eAllocation\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eX\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eINTERVENTIONS\u003c/b\u003e:\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eNO VENT group\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003eX\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eVENT group\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003eX\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eASSESSMENTS\u003c/b\u003e:\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eHeight and weight\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eX\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003ePredictive criteria of impossible bag-mask ventilation\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eX\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eX\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eOxygen saturation in ambient air\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eX\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eX\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003ePrimary outcome\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003eX\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eOxygen saturation\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003eX\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003eX\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003eX\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eBlood pressure\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003eX\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003eX\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003eX\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eAspiration/\u003c/b\u003e\u003c/p\u003e \u003cp\u003e\u003cb\u003eRegurgitation\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003eX\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003eX\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003eX\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eFailure of tracheal intubation at first attempt\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003eX\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eIntubation difficulties\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003eX\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eEsophageal intubation\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003eX\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003eX\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eDental injuries\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003eX\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003eX\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eVentilation difficulties\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003eX\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003eX\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eArrhythmias\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003eX\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003eX\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003eX\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eCardiac arrest\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003eX\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003eX\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003eX\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eNeed to use\u003c/b\u003e\u003c/p\u003e \u003cp\u003e\u003cb\u003eFiO\u003c/b\u003e\u003csub\u003e\u003cb\u003e2\u003c/b\u003e\u003c/sub\u003e\u0026thinsp;\u003cb\u003e\u0026gt;\u0026thinsp;50%\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003eX\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003eX\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eNeed of lung recruitment maneuver\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003eX\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003eX\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003ePlateau pressure\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003eX\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003eX\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eLength of stay in post-anesthesia care unit\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003eX\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eLength of MV post-operatively\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003eX\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eNeed of NIV after extubation\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003eX\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eNausea, vomiting\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003eX\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eIn-hospital length of stay\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e \u003cp\u003eX\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eDeath\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003eX\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003eX\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003eX\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003eX\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e \u003cp\u003eX\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec20\" class=\"Section2\"\u003e \u003ch2\u003eLegend (SPIRIT figure)\u003c/h2\u003e \u003cp\u003et1, general anesthesia induction; t2, from induction to 10 min after intubation; t3, during surgery; t4, in the post-anesthesia care unit.\u003c/p\u003e \u003cp\u003eNO VENT group, without bag-mask ventilation during the apneic time before intubation (unless necessary following the trial protocol).\u003c/p\u003e \u003cp\u003eVENT group, with bag-mask ventilation during the apneic time before intubation\u003c/p\u003e \u003cp\u003eMV, mechanical ventilation; NIV, non-invasive ventilation; FiO\u003csub\u003e2\u003c/sub\u003e, fraction of inspired oxygen\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec21\" class=\"Section2\"\u003e \u003ch2\u003eSample size {14}\u003c/h2\u003e \u003cp\u003eIn the PREOPTIPOP trial, which included patients with class II or higher obesity, all participants were intubated according to the NO VENT strategy [\u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e]. In the latter, 36% of the patients presented with at least one intubation-related complication, as defined in the primary outcome in the present study. Using a two-sided test with an alpha risk of 5% and a power of 80%, and adding a 5% attrition rate, 702 patients are needed (i.e., 351 patients in each group with a 1:1 ratio of randomization) to show a 10% reduction in intubation-related complications with the VENT strategy.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec22\" class=\"Section2\"\u003e \u003ch2\u003eRecruitment {15}\u003c/h2\u003e \u003cp\u003eThe inclusion and non-inclusion criteria are screened during anesthetic consultation. Clinical research associates (CRAs) and clinicians screen patients and fulfil the screening log.\u003c/p\u003e \u003cdiv id=\"Sec23\" class=\"Section3\"\u003e \u003ch2\u003eAssignment of interventions: allocation\u003c/h2\u003e \u003cdiv id=\"Sec24\" class=\"Section4\"\u003e \u003ch2\u003eSequence generation {16a}\u003c/h2\u003e \u003cp\u003eThe clinical research team screens, enrolls and randomizes the participants. Randomization is centralized, web-based, and available 24-hour a day. The allocation list is generated by a statistician. Randomization is stratified according to the type of surgery (bariatric or non-bariatric), and performed using a 1:1 ratio.\u003c/p\u003e \u003c/div\u003e \u003c/div\u003e \u003cdiv id=\"Sec25\" class=\"Section3\"\u003e \u003ch2\u003eConcealment mechanism {16b}\u003c/h2\u003e \u003cp\u003eRandomization is web-based and performed the day of the surgery, independently of the data analyst and the clinician. Randomization is sequentially numbered. Participants are assigned to the VENT or NO VENT group in a 1:1 ratio with variable block size.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec26\" class=\"Section3\"\u003e \u003ch2\u003eImplementation {16c}\u003c/h2\u003e \u003cp\u003eAt inclusion, participants are randomly assigned to the VENT or NO VENT group using computer-generated randomization. A CRA transmits the allocated group to anesthesiologist in charge of the patient.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec27\" class=\"Section3\"\u003e \u003ch2\u003eAssignment of interventions: Blinding\u003c/h2\u003e \u003cdiv id=\"Sec28\" class=\"Section4\"\u003e \u003ch2\u003eWho will be blinded {17a}\u003c/h2\u003e \u003cp\u003eNot applicable. The VENT OR NOT study is an open-label trial; participants and investigators are unblinded.\u003c/p\u003e \u003c/div\u003e \u003c/div\u003e \u003c/div\u003e \u003cdiv id=\"Sec29\" class=\"Section2\"\u003e \u003ch2\u003eProcedure for unblinding if needed {17b}\u003c/h2\u003e \u003cp\u003eProcedure for unblinding is not applicable. Investigators are aware of treatment allocation because the two intubation strategies clearly differ.\u003c/p\u003e \u003c/div\u003e\n\u003ch3\u003eData collection and management\u003c/h3\u003e\n\u003cdiv id=\"Sec31\" class=\"Section2\"\u003e \u003ch2\u003ePlans for assessment and collection of outcomes {18a}\u003c/h2\u003e \u003cp\u003eThe baseline information of each participant is recovered from the anesthetic consultation. Baseline characteristics are collected, including age, sex, height, weight, ideal body weight, body mass index, type of surgery or endoscopy, comorbidities (cardiorespiratory, otorhinolaryngology, carcinology, smoking status, and sleep apnea), oxygen saturation in ambient air, and predictive criteria for difficult ventilation or intubation (non-exhaustive list).\u003c/p\u003e \u003cp\u003eMost of the outcomes are automatically saved in the electronic anesthesia record. A spreadsheet was created to facilitate exhaustive data collection. CRAs subsequently enter all the data on the electronic Case Report Form (eCRF) via their personal online access account. Patients are followed until hospital discharge (see \u003cb\u003ethe SPIRIT figure\u003c/b\u003e).\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec32\" class=\"Section2\"\u003e \u003ch2\u003ePlans to promote participant retention and complete follow-up {18b}\u003c/h2\u003e \u003cp\u003eAs the primary outcome is collected during general anesthesia, few patients will be lost to follow-up.\u003c/p\u003e \u003cdiv id=\"Sec33\" class=\"Section3\"\u003e \u003ch2\u003eData management {19}\u003c/h2\u003e \u003cp\u003eData are recorded on an eCRF hosted on a dedicated server with controlled access. All modifications, additions, and deletions are recorded. Clinical trial data will be stored for at least 15 years after the end of the trial.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec34\" class=\"Section3\"\u003e \u003ch2\u003eConfidentiality {27}\u003c/h2\u003e \u003cp\u003eTo preserve the confidentiality of participants, they are identified using alphanumeric numbers in the eCRF.\u003c/p\u003e \u003cp\u003e \u003cb\u003ePlans for collection, laboratory evaluation and storage of biological specimens for genetic or molecular analysis in this trial/future use {33}\u003c/b\u003e \u003c/p\u003e \u003cp\u003eNo biological specimens will be collected.\u003c/p\u003e \u003c/div\u003e \u003c/div\u003e\n\u003ch3\u003eStatistical methods\u003c/h3\u003e\n\u003cdiv id=\"Sec36\" class=\"Section2\"\u003e \u003ch2\u003eStatistical methods for primary and secondary outcomes {20a}\u003c/h2\u003e \u003cp\u003eRecruitment will stop when 702 randomized patients will have undergone intubation. Continuous variables will be presented as means and standard deviations (as medians and quartiles, otherwise), and categorical data will be presented as exact numbers and percentages.\u003c/p\u003e \u003cp\u003eAnalyses will be conducted on the intention-to-treat population, defined as all randomized patients who underwent intubation (primary analysis). Patients in the NO VENT group undergoing bag-mask ventilation without desaturation\u0026thinsp;\u0026lt;\u0026thinsp;95% will be considered to meet the primary outcome in the primary analysis. Randomized patients who did not undergo intubation (i.e., surgery cancelled for logistic reasons) will not be included in the intention-to-treat analysis. The per-protocol analysis will exclude patients with non-inclusion criteria, protocol deviations, or missing data for the primary outcome.\u003c/p\u003e \u003cp\u003eThe proportion of intubation-related complications will be compared between groups using a mixed logistic regression model adjusted for stratification criterion (bariatric surgery) as a fixed effect and for center as a random effect. Secondary quantitative endpoints will be compared between the groups using mixed linear regression and secondary binary endpoints using mixed logistic regression.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec37\" class=\"Section2\"\u003e \u003ch2\u003eInterim analyses {21b}\u003c/h2\u003e \u003cp\u003eTwo interim analyses are planned for the efficacy of the primary outcome with O\u0026rsquo;Brien and Fleming\u0026rsquo;s alpha spending function approach to control for type I error: the first after the inclusion of 234 patients and the second after the inclusion of 468 patients [\u003cspan citationid=\"CR29\" class=\"CitationRef\"\u003e29\u003c/span\u003e], with respective P-values to determine the efficacy of 0.0002 and 0.012. These interim analyses are also planned to assess safety data, especially the rate of intubation-related complications, which is a point of interest for the Data and Safety Monitoring Board (see the dedicated section).\u003c/p\u003e \u003cdiv id=\"Sec38\" class=\"Section3\"\u003e \u003ch2\u003eMethods for additional analyses (e.g. subgroup analyses) {20b}\u003c/h2\u003e \u003cp\u003eAs an exploratory analysis, the primary outcome will be compared in several subgroups: bariatric vs. non-bariatric surgery; BMI\u0026thinsp;\u0026lt;\u0026thinsp;40 kg/ m\u003csup\u003e2\u003c/sup\u003e vs. BMI\u0026thinsp;\u0026ge;\u0026thinsp;40 kg/m\u003csup\u003e2\u003c/sup\u003e; oxygen saturation at the end of the preoxygenation period\u0026thinsp;\u0026lt;\u0026thinsp;97% vs. \u0026ge; 97%; direct laryngoscopy versus video-laryngoscopy as the first intubation device; and depolarizing vs. non-depolarizing neuromuscular blockers.\u003c/p\u003e \u003cp\u003eA logistic regression model will be used to compare the primary outcomes between the two groups in the above subgroup analyses. As these are exploratory analyses, no alpha risk adjustment for multiplicity is planned.\u003c/p\u003e \u003cp\u003e \u003cb\u003eMethods in analysis to handle protocol non-adherence and any statistical methods to handle missing data {20c}\u003c/b\u003e \u003c/p\u003e \u003cp\u003eThe per-protocol analysis will exclude patients with non-inclusion criteria, protocol deviations, or missing data for the primary outcome (see above). Importantly, patients from the NO VENT group receiving bag-mask ventilation without desaturation under 95% will be included in the per-protocol analysis because their exclusion could heavily bias the results against the VENT group (i.e., this strategy excludes patients likely to present desaturation in the NO VENT group and reduces the percentage of patients meeting the primary outcome). Similarly, patients in the NO VENT group who experienced desaturation under 95% with or without bag-mask ventilation will be included in the per-protocol analysis. Data on the primary outcome should not be missing, as they are collected during general anesthesia in the operating room. However, in the case of missing data, a multiple imputation procedure based on the data at inclusion will be used.\u003c/p\u003e \u003c/div\u003e \u003c/div\u003e \u003cdiv id=\"Sec39\" class=\"Section2\"\u003e \u003ch2\u003ePlans to give access to the full protocol, participant-level data and statistical code {31c}\u003c/h2\u003e \u003cp\u003eThe protocol is available on ClinicalTrials.gov since June 1, 2023. The full protocol will be published with the results of the trial. All participant-level data and statistical codes will be made available on a specific request with the authorization of the Nantes University Hospital, the leading investigator and the statistician of the study.\u003c/p\u003e \u003cdiv id=\"Sec40\" class=\"Section3\"\u003e \u003ch2\u003eOversight and monitoring\u003c/h2\u003e \u003c/div\u003e \u003c/div\u003e\n\u003ch3\u003eComposition of the coordinating center, trial steering committee and Data and Safety Monitoring Board {5d}\u003c/h3\u003e\n\u003cp\u003eThe coordinating center is Nantes University Hospital. MV is the leading investigator and leads the coordination team composed of clinicians and CRAs.\u003c/p\u003e \u003cp\u003eAt each participating center, the principal investigator is responsible for ensuring compliance with the study protocol. A specific meeting with all the members of the coordination team was organized before the start of inclusion in each center.\u003c/p\u003e \u003cp\u003eThe Data and Safety Monitoring Board (DSMB) is composed of Pr. Jean-Michel Constantin (Assistance Publique des H\u0026ocirc;pitaux de Paris, France), Pr. Emmanuel Futier (CHU de Clermont-Ferrand, France) and Lionel Velly (Assistance Publique des H\u0026ocirc;pitaux de Marseille, France). The DSMB will analyze the safety results (i.e., incidence of intubation-related complications) of the two interim analyses to decide whether the trial should be continued or stopped.\u003c/p\u003e\n\u003ch3\u003eComposition of the data monitoring committee, its role and reporting structure {21a}\u003c/h3\u003e\n\u003cp\u003eMonitoring follows Good Clinical Practice principles and is performed by the department of the Nantes University Hospital Research Management Unit. A CRA regularly visits each center to control the quality of the recorded data. CRAs can check the anesthetic report. The following data are assessed: written informed consent, flow chart for included and non-included patients, trial progress, and collection of primary and secondary outcomes. CRAs are independent of the trial coordination team to guarantee impartiality in data review.\u003c/p\u003e\n\u003ch3\u003eAdverse event reporting and harms {22}\u003c/h3\u003e\n\u003cp\u003eAdverse events are collected on the eCRF and reported to the appropriate institutional vigilance system of each center.\u003c/p\u003e\n\u003ch3\u003eFrequency and plans for auditing trial conduct {23}\u003c/h3\u003e\n\u003cp\u003eThe promotion department of the Nantes University Hospital Research Management Unit audits the involved centers. The audit will include a review of source documents and a double check of the primary outcome and all secondary outcomes (i.e., monitoring 100% of the data) for 10% of the patients. Written informed consent will be checked for 100% of the participants. The aim is to ensure the compliance of the trial protocol and the Good Clinical Practice guidelines.\u003c/p\u003e\n\u003ch3\u003ePlans for communicating important protocol amendments to relevant parties (e.g. trial participants, ethical committees) {25}\u003c/h3\u003e\n\u003cp\u003eMajor changes to the trial protocol will be reported by the promoter to the Comit\u0026eacute; de Protection des Personnes. The amended protocol will be edited, dated, and declared at ClinicalTrials.gov. The consent form will be modified accordingly, if needed.\u003c/p\u003e\n\u003ch3\u003eDissemination plans {31a}\u003c/h3\u003e\n\u003cp\u003eThe results of this study will be disseminated through presentations at scientific conferences and through publications in peer-reviewed journals.\u003c/p\u003e"},{"header":"Discussion","content":"\u003cp\u003eObesity is a public health issue because the proportion of people with a BMI over 30 kg/m\u003csup\u003e2\u003c/sup\u003e is increasing. Airway management of obese patients in the operating room is a daily challenge [\u003cspan citationid=\"CR20\" class=\"CitationRef\"\u003e20\u003c/span\u003e, \u003cspan additionalcitationids=\"CR31\" citationid=\"CR30\" class=\"CitationRef\"\u003e30\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR32\" class=\"CitationRef\"\u003e32\u003c/span\u003e]. To date, no randomized controlled trial has compared the VENT and NO VENT strategies in a large sample of obese patients. The NO VENT strategy has both positive and negative aspects.\u003c/p\u003e \u003cp\u003e \u003cul\u003e \u003cli\u003e \u003cp\u003eOn the one hand, it may reduce the risk of aspiration/regurgitation secondary to gastric insufflation related to bag-mask ventilation, especially in patients with difficult or impossible bag-mask ventilation criteria.\u003c/p\u003e \u003c/li\u003e \u003cli\u003e \u003cp\u003eOn the other hand, because apnea usually occurs quickly after the administration of hypnotics, the patient has already drawn in the oxygen reserve when anesthesia and neuromuscular blocking are deep enough to start intubation. Consequently, hypnotics and neuromuscular blockers are administered over a short period of time to reduce the delay between apnea and intubation. This does not allow titration of hypnotics according to patient consciousness and could therefore increase the risk of hypotension. Similarly, depending on the nature of the intubation sequence (i.e., depth of anesthesia and delay of action of neuromuscular blockers), the quality of glottis exposition could differ, and the rate of first-attempt success can change. Finally, neuromuscular blockers with a fast onset of action present a higher risk of anaphylaxis [\u003cspan citationid=\"CR33\" class=\"CitationRef\"\u003e33\u003c/span\u003e].\u003c/p\u003e \u003c/li\u003e \u003c/ul\u003e \u003c/p\u003e \u003cp\u003eTheoretically, the VENT strategy, including bag-mask ventilation after apnea and before intubation, could maximize the oxygen reserve before intubation. Furthermore, because apnea time is not a limiting parameter in this strategy, progressive titration of hypnotics is possible, thereby reducing the risk of side effects, such as hypotension. Nevertheless, bag-mask ventilation is sometimes difficult or impossible in obese patients, and represents a risk of gastric insufflation. Therefore, this strategy may increase the risk of aspiration/regurgitation. However, a recent large multicenter randomized controlled study demonstrated that, in critically ill patients, who were commonly reported at a very high risk of aspiration/inhalation, bag-mask ventilation did not increase aspiration/regurgitation [\u003cspan citationid=\"CR34\" class=\"CitationRef\"\u003e34\u003c/span\u003e]. Thus, uncertainty remains regarding the best intubation strategy to be adopted in obese patients worldwide.\u003c/p\u003e \u003cp\u003eThe choice of the primary outcome may be questionable. It includes components that the VENT strategy could reduce (i.e., desaturation, hypotension, or first-attempt intubation failure), and events that were reported to increase with a VENT strategy (i.e., aspiration/regurgitation). Accordingly, a significant difference between groups (i.e., reduction of desaturation, hypotension, and intubation failure without increasing aspiration/regurgitation) will bring strong results to the field of intubation in obese patients. Each component of the primary outcome will be assessed separately.\u003c/p\u003e \u003cp\u003eThe threshold of 95% for oxygen desaturation as the primary outcome may be controversial because it does not represent an immediate threat to the patient. However, this threshold is currently admitted to (re) starting bag-mask ventilation to avoid deeper desaturation [\u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e]. As the lowest saturation during the intubation procedure is also collected, we will be able to judge whether the difference between groups is relevant.\u003c/p\u003e \u003cp\u003e \u003cspan type=\"BoldUnderline\" class=\"BoldUnderline\" name=\"Emphasis\"\u003eTrial status\u003c/span\u003e \u003c/p\u003e \u003cp\u003eThe study protocol was edited in its first version on March 17, 2023. It was published at ClinicalTrials.gov on June 1, 2023 (NCT05930678). Recruitment began on September 2023, and the first patient was included on September 12, 2023. The last version of the protocol is version 3.0, which was edited on January 19, 2024. Most of the study centers have already begun inclusion. A total of 702 patients are expected to be included to complete recruitment before September 2025.\u003c/p\u003e"},{"header":"Abbreviations","content":"\u003cdiv class=\"DefinitionList\"\u003e \u003cdiv class=\"DefinitionListEntry\"\u003e \u003cdiv class=\"Term\"\u003eBiPAP\u003c/div\u003e \u003cdiv class=\"Description\"\u003e \u003cp\u003ebi-level positive airway pressure\u003c/p\u003e \u003c/div\u003e \u003c/div\u003e \u003cdiv class=\"DefinitionListEntry\"\u003e \u003cdiv class=\"Term\"\u003eBMI\u003c/div\u003e \u003cdiv class=\"Description\"\u003e \u003cp\u003ebody mass index\u003c/p\u003e \u003c/div\u003e \u003c/div\u003e \u003cdiv class=\"DefinitionListEntry\"\u003e \u003cdiv class=\"Term\"\u003eCRA\u003c/div\u003e \u003cdiv class=\"Description\"\u003e \u003cp\u003eclinical research associate\u003c/p\u003e \u003c/div\u003e \u003c/div\u003e \u003cdiv class=\"DefinitionListEntry\"\u003e \u003cdiv class=\"Term\"\u003eDSMB\u003c/div\u003e \u003cdiv class=\"Description\"\u003e \u003cp\u003eData and Safety Monitoring Board\u003c/p\u003e \u003c/div\u003e \u003c/div\u003e \u003cdiv class=\"DefinitionListEntry\"\u003e \u003cdiv class=\"Term\"\u003eeCRF\u003c/div\u003e \u003cdiv class=\"Description\"\u003e \u003cp\u003eelectronic case report form\u003c/p\u003e \u003c/div\u003e \u003c/div\u003e \u003cdiv class=\"DefinitionListEntry\"\u003e \u003cdiv class=\"Term\"\u003eFiO\u003csub\u003e2\u003c/sub\u003e\u003c/div\u003e \u003cdiv class=\"Description\"\u003e \u003cp\u003efraction of inspired oxygen\u003c/p\u003e \u003c/div\u003e \u003c/div\u003e \u003cdiv class=\"DefinitionListEntry\"\u003e \u003cdiv class=\"Term\"\u003eIDS\u003c/div\u003e \u003cdiv class=\"Description\"\u003e \u003cp\u003eintubation difficulty scale\u003c/p\u003e \u003c/div\u003e \u003c/div\u003e \u003cdiv class=\"DefinitionListEntry\"\u003e \u003cdiv class=\"Term\"\u003eMV\u003c/div\u003e \u003cdiv class=\"Description\"\u003e \u003cp\u003emechanical ventilation\u003c/p\u003e \u003c/div\u003e \u003c/div\u003e \u003cdiv class=\"DefinitionListEntry\"\u003e \u003cdiv class=\"Term\"\u003eNIV\u003c/div\u003e \u003cdiv class=\"Description\"\u003e \u003cp\u003enon-invasive ventilation\u003c/p\u003e \u003c/div\u003e \u003c/div\u003e \u003cdiv class=\"DefinitionListEntry\"\u003e \u003cdiv class=\"Term\"\u003ePEEP\u003c/div\u003e \u003cdiv class=\"Description\"\u003e \u003cp\u003eexpiratory positive airway pressure\u003c/p\u003e \u003c/div\u003e \u003c/div\u003e \u003cdiv class=\"DefinitionListEntry\"\u003e \u003cdiv class=\"Term\"\u003ePI\u003c/div\u003e \u003cdiv class=\"Description\"\u003e \u003cp\u003eprincipal investigator\u003c/p\u003e \u003c/div\u003e \u003c/div\u003e \u003cdiv class=\"DefinitionListEntry\"\u003e \u003cdiv class=\"Term\"\u003ePIP\u003c/div\u003e \u003cdiv class=\"Description\"\u003e \u003cp\u003einspiratory positive airway pressure\u003c/p\u003e \u003c/div\u003e \u003c/div\u003e \u003c/div\u003e"},{"header":"Declarations","content":"\u003cp\u003e\u003cstrong\u003eAcknowledgements\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eWe thank the patients, physicians, anesthesia nurses, and CRAs of the participating centers for their involvement in this study.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAuthors’ contributions {31b}\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eMV is the Chief Investigator; he designed the study and obtained funding. MV and MP planned the statistical analyses. MV, RD, KA, BR, SZ and GJ introduced the study protocol to the participating centers. MV and SZ will have full access to the final trial dataset. MV, SZ, RD, KA and BR drafted the manuscript. All authors have read and approved the final manuscript. For the final publication, the authors will be determined according to the proportion of patients included in each center.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eFunding {4}\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe VENT OR NOT study is supported by the French Ministry of Health (Interregional French Clinical Hospital Research Program grant\u0026nbsp;PHRC-IR 2021 API21/N/010). The Nantes University Hospital promotes this study.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAvailability of data and materials {29}\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe final de-identified trial dataset will be available to all investigators and the research team of all the participating centers.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eEthics approval and consent to participate {24}\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe study protocol was approved by the Ethics Committee CPP Est III on May 31, 2023. The trial is conducted according to the principles of the Declaration of Helsinki and the Good Clinical Practice guidelines. Patients are included after written informed consent. Clinicians ensure information and consent collection.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eConsent for publication {32}\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eAll participants are informed that their anonymized data will be used for publication.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eCompeting interests {28}\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe authors declare that they have no conflicts of interest.\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\u003cli\u003e\u003cspan\u003eProducts -HE. Stats - Prevalence of Overweight, Obesity, and Extreme Obesity Among Adults Aged 20 and Over: United States, 1960\u0026ndash;1962 Through 2017\u0026ndash;2018. 2021. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://www.cdc.gov/nchs/data/hestat/obesity-adult-17-18/obesity-adult.htm\u003c/span\u003e\u003cspan address=\"https://www.cdc.gov/nchs/data/hestat/obesity-adult-17-18/obesity-adult.htm\" targettype=\"URL\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e. Accessed 19 Jun 2024.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eWHO European Regional Obesity Report. 2022. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://www.who.int/europe/publications/i/item/9789289057738\u003c/span\u003e\u003cspan address=\"https://www.who.int/europe/publications/i/item/9789289057738\" targettype=\"URL\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e. Accessed 19 Jun 2024.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eYakushiji H, Goto T, Shirasaka W, Hagiwara Y, Watase H, Okamoto H, et al. Associations of obesity with tracheal intubation success on first attempt and adverse events in the emergency department: An analysis of the multicenter prospective observational study in Japan. PLoS ONE. 2018;13:e0195938.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eVourc\u0026rsquo;h M, Baud G, Feuillet F, Blanchard C, Mirallie E, Guitton C, et al. High-flow Nasal Cannulae Versus Non-invasive Ventilation for Preoxygenation of Obese Patients: The PREOPTIPOP Randomized Trial. EClinicalMedicine. 2019;13:112\u0026ndash;9.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eBourgain J-L, Chastre J, Combes X, Orliaguet G. [Oxygen arterial desaturation and upholding the oxygenation during intubation: question 2. Soci\u0026eacute;t\u0026eacute; Fran\u0026ccedil;aise d\u0026rsquo;Anesth\u0026eacute;sie et de R\u0026eacute;animation]. Ann Fr Anesth Reanim. 2008;27:15\u0026ndash;25.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eBourgain JL. [Preoxygenation and upper airway patency control]. Ann Fr Anesth Reanim. 2003;22(Suppl 1):s41\u0026ndash;52.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eGander S, Frascarolo P, Suter M, Spahn DR, Magnusson L. Positive end-expiratory pressure during induction of general anesthesia increases duration of nonhypoxic apnea in morbidly obese patients. Anesth Analg. 2005;100:580\u0026ndash;4.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eDelay J-M, Sebbane M, Jung B, Nocca D, Verzilli D, Pouzeratte Y, et al. The effectiveness of noninvasive positive pressure ventilation to enhance preoxygenation in morbidly obese patients: a randomized controlled study. Anesth Analg. 2008;107:1707\u0026ndash;13.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eCoussa M, Proietti S, Schnyder P, Frascarolo P, Suter M, Spahn DR, et al. Prevention of atelectasis formation during the induction of general anesthesia in morbidly obese patients. Anesth Analg. 2004;98:1491\u0026ndash;5. table of contents.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eFutier E, Constantin J-M, Pelosi P, Chanques G, Massone A, Petit A, et al. Noninvasive ventilation and alveolar recruitment maneuver improve respiratory function during and after intubation of morbidly obese patients: a randomized controlled study. Anesthesiology. 2011;114:1354\u0026ndash;63.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eNdoko SK, Amathieu R, Tual L, Polliand C, Kamoun W, El Housseini L, et al. Tracheal intubation of morbidly obese patients: a randomized trial comparing performance of Macintosh and Airtraq laryngoscopes. Br J Anaesth. 2008;100:263\u0026ndash;8.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eRuetzler K, Rivas E, Cohen B, Mosteller L, Martin A, Keebler A, et al. McGrath Video Laryngoscope Versus Macintosh Direct Laryngoscopy for Intubation of Morbidly Obese Patients: A Randomized Trial. Anesth Analg. 2020;131:586\u0026ndash;93.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eLangeron O, Masso E, Huraux C, Guggiari M, Bianchi A, Coriat P, et al. Prediction of difficult mask ventilation. Anesthesiology. 2000;92:1229\u0026ndash;36.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eKheterpal S, Martin L, Shanks AM, Tremper KK. Prediction and outcomes of impossible mask ventilation: a review of 50,000 anesthetics. Anesthesiology. 2009;110:891\u0026ndash;7.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eMaltby JR, Pytka S, Watson NC, Cowan RAM, Fick GH. Drinking 300 mL of clear fluid two hours before surgery has no effect on gastric fluid volume and pH in fasting and non-fasting obese patients. Can J Anaesth. 2004;51:111\u0026ndash;5.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eJuvin P, F\u0026egrave;vre G, Merouche M, Vallot T, Desmonts JM. Gastric residue is not more copious in obese patients. Anesth Analg. 2001;93:1621\u0026ndash;2. table of contents.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eAoragh A, Pastijn E, Cadiere GB, Kapessidou Y. Rapid sequence induction versus routine induction in obese patients scheduled for bariatric surgery: 19AP3-6. Eur J Anaesthesiol | EJA. 2013;30:257.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eAldenkortt M, Lysakowski C, Elia N, Brochard L, Tram\u0026egrave;r MR. Ventilation strategies in obese patients undergoing surgery: a quantitative systematic review and meta-analysis. Br J Anaesth. 2012;109:493\u0026ndash;502.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eDe Jong A, Roll\u0026eacute; A, Souche F-R, Yengui O, Verzilli D, Chanques G, et al. How can I manage anaesthesia in obese patients? Anaesth Crit Care Pain Med. 2020;39:229\u0026ndash;38.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eKristensen MS. Airway management and morbid obesity. Eur J Anaesthesiol. 2010;27:923\u0026ndash;7.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003ePatel A, Nouraei SaR. Transnasal Humidified Rapid-Insufflation Ventilatory Exchange (THRIVE): a physiological method of increasing apnoea time in patients with difficult airways. Anaesthesia. 2015;70:323\u0026ndash;9.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eHeinrich S, Horbach T, Prottengeier BS, Schmidt JAI. Benefits of Heated and Humidified High Flow Nasal Oxygen for Preoxygenation in Morbidly Obese Patients Undergoing Bariatric Surgery: A Randomized Controlled Study. J Obes Bariatrics. 2014;1:7.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eDixon BJ, Dixon JB, Carden JR, Burn AJ, Schachter LM, Playfair JM, et al. Preoxygenation is more effective in the 25 degrees head-up position than in the supine position in severely obese patients: a randomized controlled study. Anesthesiology. 2005;102:1110\u0026ndash;5. discussion 5A.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eAltermatt FR, Mu\u0026ntilde;oz HR, Delfino AE, Cort\u0026iacute;nez LI. Pre-oxygenation in the obese patient: effects of position on tolerance to apnoea. Br J Anaesth. 2005;95:706\u0026ndash;9.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eGibbs KW, Semler MW, Driver BE, Seitz KP, Stempek SB, Taylor C, et al. Noninvasive Ventilation for Preoxygenation during Emergency Intubation. N Engl J Med. 2024;390:2165\u0026ndash;77.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eEl-Orbany M, Woehlck HJ. Difficult mask ventilation. Anesth Analg. 2009;109:1870\u0026ndash;80.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eDiemunsch P, Langeron O, Richard M, Lenfant F. [Prediction and definition of difficult mask ventilation and difficult intubation: question 1. Soci\u0026eacute;t\u0026eacute; Fran\u0026ccedil;aise d\u0026rsquo;Anesth\u0026eacute;sie et de R\u0026eacute;animation]. Ann Fr Anesth Reanim. 2008;27:3\u0026ndash;14.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eFutier E, Constantin J-M, Paugam-Burtz C, Pascal J, Eurin M, Neuschwander A, et al. A trial of intraoperative low-tidal-volume ventilation in abdominal surgery. N Engl J Med. 2013;369:428\u0026ndash;37.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eO\u0026rsquo;Brien PC, Fleming TR. A multiple testing procedure for clinical trials. Biometrics. 1979;35:549\u0026ndash;56.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eDe Jong A, Molinari N, Pouzeratte Y, Verzilli D, Chanques G, Jung B, et al. Difficult intubation in obese patients: incidence, risk factors, and complications in the operating theatre and in intensive care units. Br J Anaesth. 2015;114:297\u0026ndash;306.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eMoon TS, Fox PE, Somasundaram A, Minhajuddin A, Gonzales MX, Pak TJ, et al. The influence of morbid obesity on difficult intubation and difficult mask ventilation. J Anesth. 2019;33:96\u0026ndash;102.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eBrodsky JB, Lemmens HJM, Brock-Utne JG, Vierra M, Saidman LJ. Morbid obesity and tracheal intubation. Anesth Analg. 2002;94:732\u0026ndash;6. table of contents.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eReddy JI, Cooke PJ, van Schalkwyk JM, Hannam JA, Fitzharris P, Mitchell SJ. Anaphylaxis is more common with rocuronium and succinylcholine than with atracurium. Anesthesiology. 2015;122:39\u0026ndash;45.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eCasey JD, Janz DR, Russell DW, Vonderhaar DJ, Joffe AM, Dischert KM, et al. Bag-Mask Ventilation during Tracheal Intubation of Critically Ill Adults. N Engl J Med. 2019;380:811\u0026ndash;21.\u003c/span\u003e\u003c/li\u003e\u003c/ol\u003e"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":false,"hideJournal":false,"highlight":"","institution":"","isAcceptedByJournal":true,"isAuthorSuppliedPdf":false,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":false,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"trials","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"trls","sideBox":"Learn more about [Trials](http://trialsjournal.biomedcentral.com/)","snPcode":"13063","submissionUrl":"https://www.editorialmanager.com/trls","title":"Trials","twitterHandle":"MedicalEvidence","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"em","reportingPortfolio":"BMC/SO AJ","inReviewEnabled":true,"inReviewRevisionsEnabled":true},"keywords":"Obesity, General anesthesia, bag-mask ventilation, tracheal intubation, intubation-related complications","lastPublishedDoi":"10.21203/rs.3.rs-4693821/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-4693821/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003ch2\u003eBackground\u003c/h2\u003e \u003cp\u003eAlmost two-thirds of the adults in Europe are overweight or obese. Obese patients are at higher risk of complications, especially during intubation. Therefore, the management of general anesthesia is crucial. Regarding intubation, there is no consensus among anesthesiologists between the two strategies: standard sequence intubation (i.e., with bag-mask ventilation between induction and intubation) vs. rapid sequence intubation (i.e., without bag-mask ventilation between induction and intubation) assuming that these patients are at high risk of inhalation and desaturation during apnea. This study aims to compare the incidence of intubation-related complications between these two strategies in severely obese patients undergoing elective surgery.\u003c/p\u003e\u003ch2\u003eMethods\u003c/h2\u003e \u003cp\u003eThe VENT OR NOT study is a prospective, multicenter, open-label, randomized trial including obese patients with a Body Mass Index\u0026thinsp;\u0026ge;\u0026thinsp;35 kg/m\u003csup\u003e2\u003c/sup\u003e requiring tracheal intubation before scheduled surgery. We will assess the superiority of the standard sequence intubation (\u0026ldquo;VENT strategy\u0026rdquo;) compared with the rapid sequence intubation (\u0026ldquo;NO VENT strategy\u0026rdquo;) to prevent intubation-related complications in 702 obese patients. Enrolment started in September 2023 in 13 French academic and non-academic hospitals and is expected to finish in September 2025. The primary outcome is a composite outcome of complications occurring from the induction of general anesthesia up to 10 min after intubation including: oxygen desaturation\u0026thinsp;\u0026lt;\u0026thinsp;95%, intubation failure on the first attempt, aspiration or regurgitation, and severe hypotension, defined as a systolic blood pressure\u0026thinsp;\u0026lt;\u0026thinsp;80 mmHg. The VENT OR NOT trial began after Ethics Committee approval has been obtained and is carried out according to the principles of the Declaration of Helsinki and the Good Clinical Practice guidelines.\u003c/p\u003e\u003ch2\u003eDiscussion\u003c/h2\u003e \u003cp\u003eThe VENT OR NOT trial is the first randomized controlled trial designed to investigate whether the \u0026ldquo;VENT strategy\u0026rdquo; reduces the risk of intubation-related complications compared with the \u0026ldquo;NO VENT strategy\u0026rdquo; for elective surgery.\u003c/p\u003e\u003ch2\u003eTrial registration:\u003c/h2\u003e \u003cp\u003eClinicalTrials.gov (NCT05930678), registered on June 1, 2023.\u003c/p\u003e","manuscriptTitle":"Intubation of obese patients in the operating room with or without bag-mask ventilation: study protocol for a randomized multicenter trial (VENT OR NOT)","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2025-05-06 06:54:47","doi":"10.21203/rs.3.rs-4693821/v1","editorialEvents":[{"type":"communityComments","content":0},{"type":"reviewerAgreed","content":"","date":"2025-04-27T16:25:51+00:00","index":0,"fulltext":""},{"type":"reviewersInvited","content":"","date":"2025-04-27T10:56:50+00:00","index":"","fulltext":""},{"type":"editorAssigned","content":"","date":"2025-04-27T10:16:46+00:00","index":"","fulltext":""},{"type":"submitted","content":"Trials","date":"2025-04-27T04:37:09+00:00","index":"","fulltext":""}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"trials","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"trls","sideBox":"Learn more about [Trials](http://trialsjournal.biomedcentral.com/)","snPcode":"13063","submissionUrl":"https://www.editorialmanager.com/trls","title":"Trials","twitterHandle":"MedicalEvidence","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"em","reportingPortfolio":"BMC/SO AJ","inReviewEnabled":true,"inReviewRevisionsEnabled":true}}],"origin":"","ownerIdentity":"7b334beb-6426-4481-82d4-2236d51b5de1","owner":[],"postedDate":"May 6th, 2025","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"published-in-journal","subjectAreas":[],"tags":[],"updatedAt":"2025-11-17T16:05:35+00:00","versionOfRecord":{"articleIdentity":"rs-4693821","link":"https://doi.org/10.1186/s13063-025-09114-z","journal":{"identity":"trials","isVorOnly":false,"title":"Trials"},"publishedOn":"2025-11-11 15:57:54","publishedOnDateReadable":"November 11th, 2025"},"versionCreatedAt":"2025-05-06 06:54:47","video":"","vorDoi":"10.1186/s13063-025-09114-z","vorDoiUrl":"https://doi.org/10.1186/s13063-025-09114-z","workflowStages":[]},"version":"v1","identity":"rs-4693821","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-4693821","identity":"rs-4693821","version":["v1"]},"buildId":"8U1c8b4HqxoKbykW_rLl7","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}