{"paper_id":"060584a5-4aa8-43a2-ac28-2d008337dc0f","body_text":"Adapted Diving Mask Bench Tests as an Autonomous Respiratory Support in Healthy Volunteer | Research Square window.SnipcartSettings = { analytics: { enabled: false } }; (function() { var accessVector = localStorage.getItem('access_vector') || ''; window.dataLayer = window.dataLayer || []; if (accessVector) { window.dataLayer.push({ user: { profile: { profileInfo: { snid: accessVector } } } }); } })(); (function(w,d,s,l,i){w[l]=w[l]||[];w[l].push({'gtm.start':new Date().getTime(),event:'gtm.js'});var f=d.getElementsByTagName(s)[0],j=d.createElement(s),dl=l!='dataLayer'?'&l='+l:'';j.async=true;j.src='https://www.googletagmanager.com/gtm.js?id='+i+dl;f.parentNode.insertBefore(j,f);})(window,document,'script','dataLayer','GTM-K279D39R'); Browse Preprints In Review Journals COVID-19 Preprints AJE Video Bytes Research Tools Research Promotion AJE Professional Editing AJE Rubriq About Preprint Platform In Review Editorial Policies Our Team Advisory Board Help Center Sign In Submit a Preprint Cite Share Download PDF Research Adapted Diving Mask Bench Tests as an Autonomous Respiratory Support in Healthy Volunteer Beatriz Arias-Arcos, Carlos Collado-Escudero, Ariela Candelario-Cáceres, and 4 more This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-73598/v1 This work is licensed under a CC BY 4.0 License Status: Posted Version 1 posted You are reading this latest preprint version Abstract Purpose The scenario of global health crisis due to SARS-CoV-2 pandemia combined with the shortage of resources in many countries has justified numerous studies to design easily replicable and economic respiratory support devices. We have developed an adapted diving mask (ADM) to be used as an autonomous and safe respiratory support. The objective was to prove a minimum positive end expiratory pressure (PEEP) with the ADM without any adverse events. Methods Bench tests was done in 22 healthy volunteers with our ADM prototype. Expiratory-inspiratory flow and pressure were registered apart from blood and transcutaneous hypercapnia. Results There were no statistically significant differences in the baseline analysis results and after therapy, except in pO2. Mean PEEP measured was 8.2 ± 4.2 cmH2O with a peak measured pressure of 20 cm H2O. Conclussions The ADM has shown good tolerance and a therapeutic manteining PEEP with no evidence of any deletereous effect or hypercapnia with its continuous use. Pulmonology Anesthesiology & Pain Medicine non-invasive ventilation COVID non-electrical device mask high flow oxygen Figures Figure 1 Figure 2 Introduction In February 2020, the World Health Organization (WHO) designated the disease caused by the new coronavirus, SARS-CoV-2, originating from Wuhan, China, as COVID-19. It was declared a public health emergency in January 2020 and a pandemic in March 2020, currently exceeding the four million confirmed cases globally. This pandemic has spread over almost the entire territory of Spain, being one of the countries with the highest number of confirmed cases. This exponential growth of cases caused the saturation of the Spanish health system, mainly of intensive care units (ICU), causing the shortage of approved ventilatory support devices and stimulating the search for effective and safe alternatives [1]. The expansion of the pandemic in the rest of the world, especially in Latin America, continues. In this way, the WHO has already warned of the \"worrying upward trend\" in Africa and Latin America area and several studies estimate that if the pandemic is not controlled, up to 190,000 people could die and up to 44 million could be infected, probably reaching the limit of their resources . [2] The interstitial pneumonia is the main lung affectation due to SARS-CoV-2, causing in 41.8% of patients an acute respiratory distress (ARDS), that will require of orotracheal intubation (OTI) or non-invasive ventilation (NIV) in 19 % of them. The mortality of ARSDS in coronavirus disease (COVID) exceeds 50% independently of ICU admission [3, 4, 5, 6]. The administration of high flow oxygen with positive pressure at the end of expiration (PEEP), represents the minimum rescue respiratory support for many patients in a situation prior to admission to the ICU (7). Although the clinical applicability of homologated PEEP-generating devices (also called continous positive airways pressure [CPAP] devices) are not very versatile, in many cases they have managed to reduce mortality and OTI. Administering a sufficient PEEP level will be able to avoid alveolar collapse and greater blood oxygenation is achieved meanwhile we provide time for the recovery of the patient or until there is the possibility of admission to the ICU. [8. 9] These approved devices have been highly demanded in the situation of sanitary crisis by SARS-CoV-2.This scenario of global health crisis combined with the shortage of resources has justified numerous studies to design easily replicable respiratory support devices, trying to alleviate the lethal effects of this pandemic. AIM OF THE STUDY The main objective of this work is to demonstrate the safety of an alternative prototype of respiratory support with an adapted diving mask (ADM) in the context of the COVID-19 pandemic. The safety will be considered proven if: A therapeutic pressure was reached (≥4cmH2O) The absence of hypercapnia demonstrated in arterial blood and through continuous monitoring of transcutaneous capnography during the use of the prototype. Materials And Methods Human Resources Sample size was calculated for a population of 310.000 inhabitants with a 95% of confidence interval and error of 20%. Twenty-two volunteers were included in the study after clinically ruling out SARS-CoV-2 infection. Volunteers with chronic controlled diseases were not excluded. All volunteers were Caucasian with a mean age of 42.45 ± 8.03 years with 86.4% males and a mean body mass index (BMI) of 25.67 kg / m2 ± 4.82. Only one of them had diabetes and in no case was there a pulmonary disease. A nurse and a physician were present during the tests. An informed consent was signed to confirm understanding of the technical protocol performed. Technical resources - Monitoring: The Aisys CS2 respirator with monitor (Datex-Ohmeda of General Electrics) was used to collect the flow and pressure signals, connecting to its side stream oxygen (O2) and carbon dioxide (CO2) sensor incorporated in the system connected in the upper connection. The record of the pressure and flow waves was carried out thanks to the iCollect software installed on an external computer. Oximetry monitoring and transcutaneous capnography (Digital monitor SENTEC Biolyne supply® with the sensor V-Sign2™ and V-STATS data processing software) were added, placing the sensor in the supraclavicular space of all patients with signal monitoring for the entire duration of the recording. Their automatic reports were generated through the V-stats software. A portable gasometer (Epoc Blood analysis system, Siemens Healthcare®) was used for the arterial blood analysis. The first sample was extracted with patient breathing ambient air and the second sample, before removing the prototype having been at least 3 hours breathing air with a 100% of oxygen by the mask. The values of pH, pCO2, PO2, HCO3 and stO2 were recorded. - Materials: Our prototype respiratory support device starts from a diving mask from Decathlon. The Easybreath™ diving mask from 2015 (Figure 1.A) was the model we modified to connect to a PEEP valve and a high flow oxygen output. A total of four 3D printed pieces were developed for this purpose by a multidisciplinary team that includes pulmonologists, emergency physicians, orthopedic surgery at the Hospital Universitario Infanta Leonor and engineers from Airbus and CT. Two of these pieces have a connector function. The remaining two are a PEEP valve with the help of a spring adjusted to the maximum pressure given and an anti-suffocation valve with the sum of a membrane already present in the original mask. The mean PEEP settled reached with the maximum clousure of the valve was 8 cmH2O. These printed pieces comply with the geometric characteristics described in UNE-EN ISO 5356-1: 2015 apt. 3 and 4. The necessary software for printing is freely accessible and distributed in standard STL format. To direct the oxygen inside the mask were assembled four Intersurgical® approved connector pieces as described below: (Figure 1.B)• T-piece 22F-22M-22M: references I1982, I1986 or I1985.• 22M-15M I1943 connector.• Estomeric connector for I1702 flowmeter.• Loose high flow branches I5018.A non-return valve was placed in the front inhalation port of the ADM, reversing the direction of the membrane that by default is in the original mask and serves as an expiratory seal in operation as a diving mask.The Figure 1.C indicates the direction of the inspiratory and expiratory flow of the patient, indicating the entrance of the oxygen flow with the arrangement of all the elements of the previously proposed system. Healthy volunteers were placed in a sitting position with the monitoring previously mentioned and the mask system connected to a high flow oxygen source (50 liter oxygen bottle) through a flowmeter adjusted to more than 15 lpm. The four pieces printed have been by stereolithography (SLA) with the Form 2 machine (Formlabs) using a biocompatible Class IIA (I) resin (Dental LT5 Clear) with high resistance to fracture and wear, following the protocols indicated by the manufacturer including cleaning after printing in isopropanol to remove excess unpolymerized resin and a post-cure step at temperature to ensure complete conversion of the resin. With this protocol it is achieved that there are no residual monomers / oligomers that can leave the material. The resins used comply with the ISO 10993-5: 2009 Not Cytotoxic, ISO 10993-10: 2010 / (R) 2014 Non Irritation, ISO 10993-10: 2010 / (R) 2014 Not a sensitizer, ISO 13485: 2016 Medical Devices (Quality Management Systems - Requirements for Regulatory Purposes) and ISO 14971: 2012 Medical Devices - Application of Risk Management to Medical Devices). Statistics All the data have been collected in the test bench and have been processed with SPSS version 22. The quantitative variables are expressed as means ± standard deviation. Categorical variables are expressed as percentages. A value of p <0.05 was considered statistically significant. Results There were no statistically significant differences in the baseline analysis results and after therapy, except in pO2. (Table1)The transcutaneous capnography records showed a CO2 minimum, maximum and mean of 31.33±4.10 mmHg, 37.01±3.87 mmHg and 34.71±3.55 mmHg respectively. The minimum oxygen saturation was 74.22±12.33%, the maximum of 100±0% and the mean of 96.72±3.41%. The printed PEEP valve was kept adjusted to a maximum closure, reaching throughout the recording a mean PEEP of 8.2±4.2 cmH2O with a peak measured pressure of 20 cm H2O. Figure 2 shows the evolution of the flow and pressure measured in a volunteer with ADM at baseline respiratory rate and tachypnea in ranges of 30 seconds. Discussion In this manuscript we report the bench test results in healthy volunteers of a new respiratory device created as a result of shortness of conventional CPAP devices in the context of COVID pandemia. Our prototype has met the standard of ventilatory support as it was designed to, presenting the most relevant characteristics of previously approved CPAP devices (easy to use and low resource requirements). No deleterious effect were observed. One of the main strengths of this prototype is its biosecurity. For most of the homologated devices, the exhaled air through the expiratory leak is not filter or it is necessary to modify the circuit to avoid aerosolization of little particles into the environment. With the use of the ADM, all the expired air will come out entirely filtered through the expiratory port where a high-efficiency electrostatic filter is adapted, solving this problem. [10] All the respiratory support present pressure fluctuation in situations of tachypnea (> 25 breaths per minute) or respiratory drive increment, due to the high demand for support by the patient. If this happen, the device could not be able to provide the adequate respiratory support, even worsening the respiratory mechanic of the subject. This problem must be keep in mind in the designs of PEEP devices, although in not autonomous devices a better compensation will be expected. In our bench test in healthy volunteers no drop of pressure was observed during the monitoring even in abrupt inhalation with no significant decrease of FiO2. This is due because the pressure in our system depends in a gran part of the high flow oxygen supplied, that must not be less than 15 lpm. The lack of interconnection leaks of the printed parts and their assembly is another cause to explain the stable pressure found in ADM. In any non-invasive respiratory therapy, the adaptation of the interface to the patient's physiognomy is the main leaks generator, being a higher pressure the main risk factor in their appearance. In our prototype, pressures greater than 10 mmHg H2O were associated with around-mask leaks appeared that caused a bad tolerability and a suboptimal therapy. Due to this, the tolerable therapeutic pressure with the minimum amount of leaks was the range of 4-10 cm H2O. Fluctuation in PEEP and maximum peak pressure in the range to consider dangerous to produce lung damage was not achieved (Peak Pressure-PEEP> 15 cmH2O) [11, 12, 13, 14]. The respirator used in our bench study is not able to quantify the around-mask leaks, as it was mainly for invasive use. There were no statistically significant differences in the variation of the gasometric parameters at baseline and after therapy, except in pO2, as a consequence of hyperoxygenation caused by the exposure to a continuous oxygen flow at 100%. This situation is called hyperoxia and surveillance is mandatory due to the possibility of causing secondary hypercapnia and promoting alveolar collapse. [15]. Hyperoxia due to external supply of oxygen can decrease the hyperventilation reflex, in patients with a tendency to retain carbon dioxide, promoting the appearance of respiratory acidosis. This is why the limitation of use for 4-5 hour shifts with intermediate breaks with less oxygen supply and a close monitoring of CO2 levels is necessary, especially in high risk patients. The monitoring of pCO2 in our sample did not show elevation above the maximum pathological threshold (pCO2> 45), ruling out hypercapnia during the registration. A tendency to mild hypocapnia (<35mmHg) without having detected any side effect. The choice of a minimum of 3 hours- monitoring was made based on the non-standardized indication of non-invasive respiratory support therapy in the hospital ward, usually indicated to let the patient have breakfast, lunch and dinner once the first acute phase with 24-72 hours of uninterrupted NIV is overcame. Alveolar collapse is another adverse event of hyperoxygenation but neither was detected in our patient. Mental status of candidates to receive NIV may varies from wide awake to the unconsciousness. In the last group re-breathing and bronchoaspiration can appear. Parenteral treatment and nutrition is recommended to avoid bronchoaspiration. In patients with conscious preserved, maintaining intravenous treatment is not mandatory, but advisable, complemented with liquid diet and might keep tight surveillance of hypercapnia. Re-breathing occurs if the patient breathes in his own previously exhaled air with a high carbonic concentration. This would take place if the circuit does not have a release valve where the expired air can escape or if the arrangement of the system eases its recirculation. In the ADM prototype, the release valve is placed at the top of the mask, where the air flow will exit through the high-efficiency electrostatic filter and the PEEP valve. The location of an anti-return membrane in the outside-in direction is directed to avoid the recirculation of the exhaled air inside the ADM, permitting the high flow oxygen to penetrate into the mask. This way, we will prevent the patient exhaled air from drifting back to the oxygen connection. Thereby, the continuous flow of oxygen will ease the upward direction of the circulating air inside the mask, finally leaving through the upper exhalation port. (Figure 1.C). To allow the patient normal breathing if the flow system fails, our prototype has an anti-suffocation valve to take in air from the ambient if it is necessary. Ventilator-induced lung injury (VILI) can occur in ARDS ventilated patients. COVID-19 patients with ARSD generates a high inspiratory demand in a normally compliant lung. This high demand can generate peak inspiratory pressures greater than 25 mmHg, which can be damaging to the lung causing barotrauma (pneumomediastinum and pneumothorax), volutrauma (if higher flow is provided) and atelectrauma. Also, the presence of high peak pressures in normally compliant lungs and in a situation in which the patient has a high respiratory drive, can generate alveolar shear forces that end up generating lung injury due to the wide fluctuation of pressures between the granted and the demanded by the patient. Despite in our registry there were no Peak Pressure - PEEP> 15 cmH2O, it is important to mention that the study population profile is not that expected in the patients usually subsidiary to this respiratory support. (11, 12, 13, 14) A limiting factor in the use of PEEP autonomous devices is the need of a high flow oxygen supply through a flowmeter that supplies more than 15 lpm). This is due because with a lower flow, a sufficient pressure is not reached for the autonomous PEEP valve to be functional. It is estimated that for the continuous treatment for 4 hours, a 50-liter cylinder of liquid oxygen would be consumed. In a hospital with access to a wall-mounted oxygen output, this is not a problem. However, in circumstances of scarce resources or in developing countries this can limit the use of this devices. Nowadays our prototype has not solved this problem but our team is working on it. Conclusions We must remind that the respiratory support of choice in patients with ARDS is invasive mechanical ventilation with OTI. This is not different in COVID patients. However, in a situation of global health crisis, the shortage of resources and hospitals with overflowing ICUs, respiratory support with NIV is mandatory pending the patient's own favorable evolution or the possibility of admission to the ICU later on [16, 17, 18]. In places without access to first level health resources, the possibility of having autonomous respiratory support devices becomes more necessary as could help many of these patients [19] Our aim is not to validate a prototype to use in normal circumstances, but to validate the safety of the clinical use of our ADM as an alternative to other CPAP devices, at exceptional times and in a context of shortages of other homologated devices. This prototype does not require electronic equipment and also due to the characteristics of the materials with which it has been made, it is fully reusable after sterilization. This provides added value for exports to developing countries, in which the existences of autonomous and reusable devices can bring hope to patients who do not even have an option to be admitted to an ICU [20, 21]. Declarations Ethics approval The study has been developed after the sign of the informed consent of the healthy volunteers and approval of pertinent authorities Consent to participate The study has been developed after approval of pertinent authorities Consent for publication Not Applicable Availability of data and material All data collected is available under request Conflicts of interest/Competing interests The authors declare no conflicts of interests Funding The study was financed and carried out thanks to Banco Santander and the assignment of its staff and facilities.Decathlon Spain gave the Easybreath masks to carry out the entire project.The design and study of materials for the parts adapted for the prototype was carried out by AIRBUS and CT engineers Printed pieces used were thanks to CSIC (ICTP-CSIC) Authors' contributions BA analysed and interpreted the patients data. CC collected the data. AC helped to review the bibliography. MJB. Supervised the manuscript. AA facilitated the machines to collect the data; JMM facilitate the installations to carry out the tests and supervise them, RL coordinated the tests. Acknoledgements The study was financed and carried out thanks to Banco Santander and the assignment of its staff and facilities.Decathlon Spain gave the Easybreath masks to carry out the entire project.The design and study of materials for the parts adapted for the prototype was carried out by AIRBUS (Juan Manuel Canalejo) and CT engineers (Alberto Molina)Printed pieces used were thanks to Juan Rodriguez Hernández of the CSIC (ICTP-CSIC)Thanks to Angel Manuel Sevillano for the review of the papper. Abbreviations ADM - adapted diving mask ARDS - acute respiratory distress BMI - body mass index CO2 - carbon dioxide COVID-19 – Coronavirus infectious disease CPAP - continous positive airways pressure ICU - intensive care units NIV - non-invasive ventilation O2 - oxygen OTI -orotracheal intubation PEEP - positive pressure at the end of expiration SLA - stereolithography VILI - Ventilator-induced lung injury WHO - World Health Organization References Ministerio de Sanidad. España. Informe nº 31. Situación de COVID-19 en España a 14 de mayo de 2020. Equipo COVID-19. RENAVE. CNE. CNM (ISCIII) https://www.mscbs.gob.es/ World Health Organization. Coronavirus disease (COVID-19) outbreak. Available in: https://www.who.int Chaomin Wu, MD; Xiaoyan Chen, MD; Yanping Cai, MD; Jia’an Xia, MD; Xing Zhou, MD; Sha Xu, MD; Risk Factors Associated With Acute Respiratory Distress Syndrome and Death in Patients With Coronavirus Disease 2019 Pneumonia in Wuhan, China JAMA Intern Med . doi:10.1001/jamainternmed.2020.0994 Bellani G, Laffey JG, Pham T, et al. Epidemiology, patterns of care, and mortality for patients with acute respiratory distress syndrome in intensive care units in 50 JAMA 2016;315:788-800. Yang X, Yu Y, Xu J, et al. Clinical course and outcomes of critically ill patients with SARS-CoV-2 pneumonia in Wuhan, China: a single-centered, retrospective, observational Lancet Respir Med 2020. doi: 10.1016/S2213-2600(20)30079-5 Zhou F, Yu T, Du R, et al. Clinical course and risk factors for mortality of adult inpatients with COVID-19 in Wuhan, China: a retrospective cohort study. Lancet 2020:395:1054-62. doi: 10.1016/S0140-6736(20)30566-3. Cinesi Gómez C, Ó. Peñuelas Rodríguez, M.l Luján Torné, C. Egea Santaolalla, J.F. Masa Jiménez, J. García Fernández et al. Recomendaciones de consenso respecto al soporte respiratorio no invasivo en el paciente adulto con insuficiencia respiratoria aguda secundaria a infección por SARS-CoV-2. Rev Esp Anestesiol 2020. https://doi.org/10.1016/j.redar.2020.03.006 . Farré R, Montserrat JM, Solana G, Gozal D, Navajas D. Easy-to-build and affordable continuous positive airway pressure CPAP device for adult patients in low-income countries. Eur Respir J. 2019;53(5). Olivieri C, Costa R, Conti G, Navalesi P. Bench studies evaluating devices for non-invasive ventilation: critical analysis and future perspectives. Intensive Care Med [Internet]. 2012 Jan 29;38(1):160–7. http://link.springer.com/10.1007/s00134-011-2416-9 Simonds AK, Hanak A, Chatwin M, Morrell M, Hall A, Parker KH, et al. Evaluation of droplet dispersion during non-invasive ventilation, oxygen therapy, nebuliser treatment and chest physiotherapy in clinical practice: implications for management of pandemic influenza and other airborne infections. Health technology assessment (Winchester, England). 2010;14(46):131-72. Cressoni M, Gotti M, Chiurazzi C, Massari D, Algieri I, Amini M, Cammaroto A, Brioni M, Montaruli C, Nikolla K, Guanziroli M, Dondossola D, Gatti S, Valerio V, Vergani GL, Pugni P, Cadringher P, Gagliano N, Gattinoni L. Mechanical power and development of ventilator-induced lung injury. Anesthesiology. 2016;124:1100 –8. Silva PL, Ball L, Rocco PRM, Pelosi P. Power to mechanical power to reduce ventilator induced lung injury? Intensive Care Med Exp. 2019;7(Suppl 1):38: 1–11. https://doi.org/10.1186/s40635-019-0243-4. Tonetti T 1 , Vasques F 1 , Rapetti F 1 , Maiolo G 1 , Collino F 1 , Romitti F Driving pressure and mechanical power: new targets for VILI prevention. Ann Transl Med.2017 Jul;5(14):286. doi: 10.21037/atm.2017.07.08. Marini JJl. How I optimize power to avoid VILI. Crit Care. 2019 Oct 21;23(1):326. doi: 10.1186/s13054-019-2638-8. Brugniaux JV 1 , Coombs GB 2 , Barak OF 3,4 , Dujic Z 5 , Sekhon MS 2,6 , Ainslie PN 2 . Highs and lows of hyperoxia: physiological, performance, and clinical aspects. Am J Physiol Regul Integr Comp Physiol.2018 Jul 1;315(1):R1-R27 Rochwerg B, Brochard L, Elliott MW, Hess D, Hill NS, Nava S, et al. Official ERS/ATS clinical practice guidelines: noninvasive ventilation for acute respiratory failure. Eur Respir J [Internet]. 2017 Aug 31;50(2):1602426. http://erj.ersjournals.com/lookup/doi/10.1183/13993003.02426-2016 Alhazzani W, Møller MH, Arabi YM, Loeb M, Gong MN, Fan E, Oczkowski S, Levy MM, Derde L, Dzierba A, Du B, Aboodi M, Wunsch H, Cecconi M, Koh Y, Chertow DS, Maitland K, Alshamsi F, Belley-Cote E, Greco M, Laundy M, Morgan JS, Kesecioglu J,McGeer A, Mermel L, Mammen MJ, Alexander PE, Arrington A, Centofanti JE, Citerio G, Baw B, Memish ZA, Hammond N, Hayden FG, Evans L, Rhodes A. Surviving Sepsis Campaign: Guidelines on the Management of Critically Ill Adults with Coronavirus Disease 2019 (COVID-19 ). Crit Care Med. 2020 Mar 27. doi: 10.1097/CCM.0000000000004363. Ji Y, Ma Z, Peppelenbosch MP, Pan Q. Potential association between COVID-19 mortality and healthcare resource availability. Lancet Glob Health. 2020, http://dx.doi.org/10.1016/S2214-109X(20)30068-1. Truog RD, Mitchell C, Daley CQ. The Toughest Triage — Allocating Ventilators in a Pandemic. New Eng J Med, in press. DOI: 10.1056/NEJMp2005689. Murthy S, Leligdowicz A, Adhikari NKJ. Intensive Care Unit Capacity in Low-Income Countries: A Systematic Review. Azevedo LCP, editor. PLoS One [Internet]. 2015 Jan 24;10(1): e0116949. http://dx.plos.org/10.1371/journal.pone.0116949 Mandelzweig K, Leligdowicz A, Murthy S, Lalitha R, Fowler RA, Adhikari NKJ. Non-invasive ventilation in children and adults in low- and low-middle income countries: A systematic review and meta-analysis. J Crit Care [Internet]. 2018 Oct;47:310–9. https://linkinghub.elsevier.com/retrieve/pii/S0883944117302472 Tables Table 1 . Baseline arterial blood gases (ABG) Values and Previous Withdrawal of ADM pH pCO2 ( mmHg ) pO2 ( mmHg ) HCO3 ( mmHg ) stO2 (%) Baseline ABG 7,42 38,43 91,68 25,26 96,75 ABG with ADM 7,42 41,22 520,99 26,97 99,94 P 0,63 0,51 0,00 0,51 0,98 Supplementary Files COREQADM.docx Cite Share Download PDF Status: Posted Version 1 posted 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. Our growing team is made up of researchers and industry professionals working together to solve the most critical problems facing scientific publishing. Also discoverable on Platform About Our Team In Review Editorial Policies Advisory Board Help Center Resources Author Services Accessibility API Access RSS feed Manage Cookie Preferences © Research Square 2026 | ISSN 2693-5015 (online) Privacy Policy Terms of Service Do Not Sell My Personal Information {\"props\":{\"pageProps\":{\"initialData\":{\"identity\":\"rs-73598\",\"acceptedTermsAndConditions\":true,\"allowDirectSubmit\":true,\"archivedVersions\":[],\"articleType\":\"Research\",\"associatedPublications\":[],\"authors\":[{\"id\":2468608,\"identity\":\"0ca672ce-6e35-4a02-9556-18f78d12fafe\",\"order_by\":0,\"name\":\"Beatriz Arias-Arcos\",\"email\":\"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAAAz0lEQVRIiWNgGAWjYDACCSBOYGCQ4wdxEgpI0GIs2QBiGBCrBQgSNxwAUcRo0Z3d/OzDg5o6Y+PzqxM/PDBgkOcXO4Bfi9mdY8YzEo4dljO78XazBNBhhjNnJxDQciPBmCGB7YCx2Y2zG0BaEgxuE9SS/pkh4V9d4uYZZzf/IFJLjjFDYhtz4gb+3m1E2nLnTDFDYt9hY4kbvNssEgwkiPDL7fbNjD++1cnx95/dfPNHhY08vzQBLQggAVYpQaxyEOA/QIrqUTAKRsEoGEkAAOFvR59NVKb2AAAAAElFTkSuQmCC\",\"orcid\":\"https://orcid.org/0000-0001-5799-9255\",\"institution\":\"Hospital Universitario Infanta Leonor\",\"correspondingAuthor\":true,\"submittingAuthor\":false,\"prefix\":\"\",\"firstName\":\"Beatriz\",\"middleName\":\"\",\"lastName\":\"Arias-Arcos\",\"suffix\":\"\"},{\"id\":2468609,\"identity\":\"b8cd3415-30ea-4d4d-bd08-ef93769f4f34\",\"order_by\":1,\"name\":\"Carlos Collado-Escudero\",\"email\":\"\",\"orcid\":\"\",\"institution\":\"Hospital Universitario Infanta Leonor\",\"correspondingAuthor\":false,\"submittingAuthor\":false,\"prefix\":\"\",\"firstName\":\"Carlos\",\"middleName\":\"\",\"lastName\":\"Collado-Escudero\",\"suffix\":\"\"},{\"id\":2468610,\"identity\":\"69300714-a05c-4388-98ef-ec31e784a94a\",\"order_by\":2,\"name\":\"Ariela Candelario-Cáceres\",\"email\":\"\",\"orcid\":\"\",\"institution\":\"Hospital Universitario Infanta Leonor\",\"correspondingAuthor\":false,\"submittingAuthor\":false,\"prefix\":\"\",\"firstName\":\"Ariela\",\"middleName\":\"\",\"lastName\":\"Candelario-Cáceres\",\"suffix\":\"\"},{\"id\":2468611,\"identity\":\"e7d3cf72-fd8e-44fe-b260-7e7de20aebd5\",\"order_by\":3,\"name\":\"Maria Jesus Buendia-García\",\"email\":\"\",\"orcid\":\"\",\"institution\":\"Hospital Universitario Infanta Leonor\",\"correspondingAuthor\":false,\"submittingAuthor\":false,\"prefix\":\"\",\"firstName\":\"Maria\",\"middleName\":\"Jesus\",\"lastName\":\"Buendia-García\",\"suffix\":\"\"},{\"id\":2468612,\"identity\":\"55cc9f69-2a1f-47c0-a212-b4bb5ccd90ae\",\"order_by\":4,\"name\":\"Alfredo Abad-Gurumeta\",\"email\":\"\",\"orcid\":\"\",\"institution\":\"Hospital Universitario Infanta Leonor\",\"correspondingAuthor\":false,\"submittingAuthor\":false,\"prefix\":\"\",\"firstName\":\"Alfredo\",\"middleName\":\"\",\"lastName\":\"Abad-Gurumeta\",\"suffix\":\"\"},{\"id\":2468613,\"identity\":\"f81c3a11-fdab-41f5-bd71-39f46a26bf4a\",\"order_by\":5,\"name\":\"Jose María Mendiguren-Santiago\",\"email\":\"\",\"orcid\":\"\",\"institution\":\"Centro Médico Banco Santander\",\"correspondingAuthor\":false,\"submittingAuthor\":false,\"prefix\":\"\",\"firstName\":\"Jose\",\"middleName\":\"María\",\"lastName\":\"Mendiguren-Santiago\",\"suffix\":\"\"},{\"id\":2468614,\"identity\":\"7e2c0265-170f-4015-bf6d-ceb209b1dc5c\",\"order_by\":6,\"name\":\"Ricardo Larrainzar-Garijo\",\"email\":\"\",\"orcid\":\"\",\"institution\":\"Hospital Universitario Infanta Leonor\",\"correspondingAuthor\":false,\"submittingAuthor\":false,\"prefix\":\"\",\"firstName\":\"Ricardo\",\"middleName\":\"\",\"lastName\":\"Larrainzar-Garijo\",\"suffix\":\"\"}],\"badges\":[],\"createdAt\":\"2020-09-07 11:17:48\",\"currentVersionCode\":1,\"declarations\":\"\",\"doi\":\"10.21203/rs.3.rs-73598/v1\",\"doiUrl\":\"https://doi.org/10.21203/rs.3.rs-73598/v1\",\"draftVersion\":[],\"editorialEvents\":[],\"editorialNote\":\"\",\"failedWorkflow\":false,\"files\":[{\"id\":2539191,\"identity\":\"f55a2b1a-ccde-4858-89c5-41e0f0120b5a\",\"added_by\":\"auto\",\"created_at\":\"2020-09-22 16:47:38\",\"extension\":\"jpg\",\"order_by\":1,\"title\":\"Figure 1\",\"display\":\"\",\"copyAsset\":false,\"role\":\"figure\",\"size\":42867,\"visible\":true,\"origin\":\"\",\"legend\":\"A. Diving mask in its original formate. B. 3D printed pieces, O-ring seal, modificated mask and standard high efficacy filter and Intersurgical® oxygen connections. C. Air flow circuit from inside to outside the mask. \",\"description\":\"\",\"filename\":\"Fig1.JPG\",\"url\":\"https://assets-eu.researchsquare.com/files/rs-73598/v1/Fig1.JPG\"},{\"id\":2539192,\"identity\":\"2ed381c1-dd00-4c9f-ab10-ce60fb2d385e\",\"added_by\":\"auto\",\"created_at\":\"2020-09-22 16:47:38\",\"extension\":\"jpg\",\"order_by\":2,\"title\":\"Figure 2\",\"display\":\"\",\"copyAsset\":false,\"role\":\"figure\",\"size\":61938,\"visible\":true,\"origin\":\"\",\"legend\":\"Flow and Pressure curves in 30 seconds ranges. Normal breathing to hyperventilation.\",\"description\":\"\",\"filename\":\"Fig2.JPG\",\"url\":\"https://assets-eu.researchsquare.com/files/rs-73598/v1/Fig2.JPG\"},{\"id\":13594784,\"identity\":\"99424250-7ebf-4940-ae56-af7dab9ef5f6\",\"added_by\":\"auto\",\"created_at\":\"2021-09-17 05:21:48\",\"extension\":\"pdf\",\"order_by\":0,\"title\":\"\",\"display\":\"\",\"copyAsset\":false,\"role\":\"manuscript-pdf\",\"size\":378929,\"visible\":true,\"origin\":\"\",\"legend\":\"\",\"description\":\"\",\"filename\":\"manuscript.pdf\",\"url\":\"https://assets-eu.researchsquare.com/files/rs-73598/v1/0700f51b-141d-4223-a14f-26b305c085e2.pdf\"},{\"id\":2539194,\"identity\":\"c438ff2a-74af-4d28-b121-6f714501fe22\",\"added_by\":\"auto\",\"created_at\":\"2020-09-22 16:47:39\",\"extension\":\"docx\",\"order_by\":1,\"title\":\"\",\"display\":\"\",\"copyAsset\":false,\"role\":\"supplement\",\"size\":13405,\"visible\":true,\"origin\":\"\",\"legend\":\"\",\"description\":\"\",\"filename\":\"COREQADM.docx\",\"url\":\"https://assets-eu.researchsquare.com/files/rs-73598/v1/COREQADM.docx\"}],\"financialInterests\":\"\",\"formattedTitle\":\"\\u003cp\\u003eAdapted Diving Mask Bench Tests as an Autonomous Respiratory Support in Healthy Volunteer\\u003c/p\\u003e\",\"fulltext\":[{\"header\":\"Introduction\",\"content\":\"\\u003cp\\u003eIn February 2020, the World Health Organization (WHO) designated the disease caused by the new coronavirus, SARS-CoV-2, originating from Wuhan, China, as COVID-19. It was declared a public health emergency in January 2020 and a pandemic in March 2020, currently exceeding the four million confirmed cases globally. This pandemic has spread over almost the entire territory of Spain, being one of the countries with the highest number of confirmed cases. This exponential growth of cases caused the saturation of the Spanish health system, mainly of intensive care units (ICU), causing the shortage of approved ventilatory support devices and stimulating the search for effective and safe alternatives [1]. The expansion of the pandemic in the rest of the world, especially in Latin America, continues. In this way, the WHO has already warned of the \\\"worrying upward trend\\\" in Africa and Latin America area and several studies estimate that if the pandemic is not controlled, up to 190,000 people could die and up to 44 million could be infected, probably reaching the limit of their resources . [2]\\u003c/p\\u003e\\n\\u003cp\\u003eThe interstitial pneumonia is the main lung affectation due to SARS-CoV-2, causing in 41.8% of patients an acute respiratory distress (ARDS), that will require of orotracheal intubation (OTI) or non-invasive ventilation (NIV) in 19 % of them. The mortality of ARSDS in coronavirus disease (COVID) exceeds 50% independently of ICU admission [3, 4, 5, 6]. The administration of high flow oxygen with positive pressure at the end of expiration (PEEP), represents the minimum rescue respiratory support for many patients in a situation prior to admission to the ICU (7). Although the clinical applicability of homologated PEEP-generating devices (also called continous positive airways pressure [CPAP] devices) are not very versatile, in many cases they have managed to reduce mortality and OTI. Administering a sufficient PEEP level will be able to avoid alveolar collapse and greater blood oxygenation is achieved meanwhile we provide time for the recovery of the patient or until there is the possibility of admission to the ICU. [8. 9] These approved devices have been highly demanded in the situation of sanitary crisis by SARS-CoV-2.This scenario of global health crisis combined with the shortage of resources has justified numerous studies to design easily replicable respiratory support devices, trying to alleviate the lethal effects of this pandemic.\\u003c/p\\u003e\\n\\u003cp\\u003e\\u003cstrong\\u003eAIM OF THE STUDY\\u003c/strong\\u003e\\u003c/p\\u003e\\n\\u003cp\\u003eThe main objective of this work is to demonstrate the safety of an alternative prototype of respiratory support with an adapted diving mask (ADM) in the context of the COVID-19 pandemic. The safety will be considered proven if:\\u003c/p\\u003e\\n\\u003cul\\u003e\\n\\u003cli\\u003eA therapeutic pressure was reached (\\u0026ge;4cmH2O)\\u003c/li\\u003e\\n\\u003cli\\u003eThe absence of hypercapnia demonstrated in arterial blood and through continuous monitoring of transcutaneous capnography during the use of the prototype.\\u003c/li\\u003e\\n\\u003c/ul\\u003e\"},{\"header\":\"Materials And Methods\",\"content\":\"\\u003cp\\u003e\\u003cu\\u003eHuman Resources\\u003c/u\\u003e\\u003c/p\\u003e\\n\\u003cp\\u003eSample size was calculated for a population of 310.000 inhabitants with a 95% of confidence interval and error of 20%. Twenty-two volunteers were included in the study after clinically ruling out SARS-CoV-2 infection. Volunteers with chronic controlled diseases were not excluded.\\u003c/p\\u003e\\n\\u003cp\\u003eAll volunteers were Caucasian with a mean age of 42.45 \\u0026plusmn; 8.03 years with 86.4% males and a mean body mass index (BMI) of 25.67 kg / m2 \\u0026plusmn; 4.82. Only one of them had diabetes and in no case was there a pulmonary disease.\\u003c/p\\u003e\\n\\u003cp\\u003eA nurse and a physician were present during the tests. An informed consent was signed to confirm understanding of the technical protocol performed.\\u003c/p\\u003e\\n\\u003cp\\u003e\\u003cu\\u003eTechnical resources\\u003c/u\\u003e\\u003c/p\\u003e\\n\\u003cp\\u003e- Monitoring: The Aisys CS2 respirator with monitor (Datex-Ohmeda of General Electrics) was used to collect the flow and pressure signals, connecting to its side stream oxygen (O2) and carbon dioxide (CO2) sensor incorporated in the system connected in the upper connection. The record of the pressure and flow waves was carried out thanks to the iCollect software installed on an external computer. Oximetry monitoring and transcutaneous capnography (Digital monitor SENTEC Biolyne supply\\u0026reg; with the sensor V-Sign2\\u0026trade; and V-STATS data processing software) were added, placing the sensor in the supraclavicular space of all patients with signal monitoring for the entire duration of the recording. Their automatic reports were generated through the V-stats software.\\u003c/p\\u003e\\n\\u003cp\\u003eA portable gasometer (Epoc Blood analysis system, Siemens Healthcare\\u0026reg;) was used for the arterial blood analysis. The first sample was extracted with patient breathing ambient air and the second sample, before removing the prototype having been at least 3 hours breathing air with a 100% of oxygen by the mask. The values of pH, pCO2, PO2, HCO3 and stO2 were recorded.\\u003c/p\\u003e\\n\\u003cp\\u003e- Materials: Our prototype respiratory support device starts from a diving mask from Decathlon. The Easybreath\\u0026trade; diving mask from 2015 (Figure 1.A) was the model we modified to connect to a PEEP valve and a high flow oxygen output. A total of four 3D printed pieces were developed for this purpose by a multidisciplinary team that includes pulmonologists, emergency physicians, orthopedic surgery at the Hospital Universitario Infanta Leonor and engineers from Airbus and CT. Two of these pieces have a connector function. The remaining two are a PEEP valve with the help of a spring adjusted to the maximum pressure given and an anti-suffocation valve with the sum of a membrane already present in the original mask. The mean PEEP settled reached with the maximum clousure of the valve was 8 cmH2O. These printed pieces comply with the geometric characteristics described in UNE-EN ISO 5356-1: 2015 apt. 3 and 4. The necessary software for printing is freely accessible and distributed in standard STL format. To direct the oxygen inside the mask were assembled four Intersurgical\\u0026reg; approved connector pieces as described below: (Figure 1.B)\\u0026bull; T-piece 22F-22M-22M: references I1982, I1986 or I1985.\\u0026bull; 22M-15M I1943 connector.\\u0026bull; Estomeric connector for I1702 flowmeter.\\u0026bull; Loose high flow branches I5018.A non-return valve was placed in the front inhalation port of the ADM, reversing the direction of the membrane that by default is in the original mask and serves as an expiratory seal in operation as a diving mask.The Figure 1.C indicates the direction of the inspiratory and expiratory flow of the patient, indicating the entrance of the oxygen flow with the arrangement of all the elements of the previously proposed system.\\u003c/p\\u003e\\n\\u003cp\\u003eHealthy volunteers were placed in a sitting position with the monitoring previously mentioned and the mask system connected to a high flow oxygen source (50 liter oxygen bottle) through a flowmeter adjusted to more than 15 lpm.\\u003c/p\\u003e\\n\\u003cp\\u003eThe four pieces printed have been by stereolithography (SLA) with the Form 2 machine (Formlabs) using a biocompatible Class IIA (I) resin (Dental LT5 Clear) with high resistance to fracture and wear, following the protocols indicated by the manufacturer including cleaning after printing in isopropanol to remove excess unpolymerized resin and a post-cure step at temperature to ensure complete conversion of the resin. With this protocol it is achieved that there are no residual monomers / oligomers that can leave the material. The resins used comply with the ISO 10993-5: 2009 Not Cytotoxic, ISO 10993-10: 2010 / (R) 2014 Non Irritation, ISO 10993-10: 2010 / (R) 2014 Not a sensitizer, ISO 13485: 2016 Medical Devices (Quality Management Systems - Requirements for Regulatory Purposes) and ISO 14971: 2012 Medical Devices - Application of Risk Management to Medical Devices).\\u003c/p\\u003e\\n\\u003cp\\u003e\\u0026nbsp;\\u003cstrong\\u003eStatistics\\u003c/strong\\u003e\\u003c/p\\u003e\\n\\u003cp\\u003eAll the data have been collected in the test bench and have been processed with SPSS version 22. The quantitative variables are expressed as means \\u0026plusmn; standard deviation. Categorical variables are expressed as percentages. A value of p \\u0026lt;0.05 was considered statistically significant.\\u003c/p\\u003e\"},{\"header\":\"Results\",\"content\":\"\\u003cp\\u003eThere were no statistically significant differences in the baseline analysis results and after therapy, except in pO2. (Table1)The transcutaneous capnography records showed a CO2 minimum, maximum and mean of 31.33\\u0026plusmn;4.10 mmHg, 37.01\\u0026plusmn;3.87 mmHg and 34.71\\u0026plusmn;3.55 mmHg respectively. The minimum oxygen saturation was 74.22\\u0026plusmn;12.33%, the maximum of 100\\u0026plusmn;0% and the mean of 96.72\\u0026plusmn;3.41%. The printed PEEP valve was kept adjusted to a maximum closure, reaching throughout the recording a mean PEEP of 8.2\\u0026plusmn;4.2 cmH2O with a peak measured pressure of 20 cm H2O. Figure 2 shows the evolution of the flow and pressure measured in a volunteer with ADM at baseline respiratory rate and tachypnea in ranges of 30 seconds.\\u003c/p\\u003e\"},{\"header\":\"Discussion\",\"content\":\"\\u003cp\\u003eIn this manuscript we report the bench test results in healthy volunteers of a new respiratory device created as a result of shortness of conventional CPAP devices in the context of COVID pandemia. Our prototype has met the standard of ventilatory support as it was designed to, presenting the most relevant characteristics of previously approved CPAP devices (easy to use and low resource requirements). No deleterious effect were observed.\\u003c/p\\u003e\\n\\u003cp\\u003eOne of the main strengths of this prototype is its biosecurity. For most of the homologated devices, the exhaled air through the expiratory leak is not filter or it is necessary to modify the circuit to avoid aerosolization of little particles into the environment. With the use of the ADM, all the expired air will come out entirely filtered through the expiratory port where a high-efficiency electrostatic filter is adapted, solving this problem. [10]\\u003c/p\\u003e\\n\\u003cp\\u003eAll the respiratory support present pressure fluctuation in situations of tachypnea (\\u0026gt; 25 breaths per minute) or respiratory drive increment, due to the high demand for support by the patient. If this happen, the device could not be able to provide the adequate respiratory support, even worsening the respiratory mechanic of the subject. This problem must be keep in mind in the designs of PEEP devices, although in not autonomous devices a better compensation will be expected.\\u003c/p\\u003e\\n\\u003cp\\u003eIn our bench test in healthy volunteers no drop of pressure was observed during the monitoring even in abrupt inhalation with no significant decrease of FiO2. This is due because the pressure in our system depends in a gran part of the high flow oxygen supplied, that must not be less than 15 lpm. The lack of interconnection leaks of the printed parts and their assembly is another cause to explain the stable pressure found in ADM.\\u003c/p\\u003e\\n\\u003cp\\u003eIn any non-invasive respiratory therapy, the adaptation of the interface to the patient's physiognomy is the main leaks generator, being a higher pressure the main risk factor in their appearance. In our prototype, pressures greater than 10 mmHg H2O were associated with around-mask leaks appeared that caused a bad tolerability and a suboptimal therapy. Due to this, the tolerable therapeutic pressure with the minimum amount of leaks was the range of 4-10 cm H2O. Fluctuation in PEEP and maximum peak pressure in the range to consider dangerous to produce lung damage was not achieved (Peak Pressure-PEEP\\u0026gt; 15 cmH2O) [11, 12, 13, 14]. The respirator used in our bench study is not able to quantify the around-mask leaks, as it was mainly for invasive use.\\u003c/p\\u003e\\n\\u003cp\\u003eThere were no statistically significant differences in the variation of the gasometric parameters at baseline and after therapy, except in pO2, as a consequence of hyperoxygenation caused by the exposure to a continuous oxygen flow at 100%. This situation is called hyperoxia and surveillance is mandatory due to the possibility of causing secondary hypercapnia and promoting alveolar collapse. [15]. Hyperoxia due to external supply of oxygen can decrease the hyperventilation reflex, in patients with a tendency to retain carbon dioxide, promoting the appearance of respiratory acidosis. This is why the limitation of use for 4-5 hour shifts with intermediate breaks with less oxygen supply and a close monitoring of CO2 levels is necessary, especially in high risk patients.\\u003cbr /\\u003e The monitoring of pCO2 in our sample did not show elevation above the maximum pathological threshold (pCO2\\u0026gt; 45), ruling out hypercapnia during the registration. A tendency to mild hypocapnia (\\u0026lt;35mmHg) without having detected any side effect. The choice of a minimum of 3 hours- monitoring was made based on the non-standardized indication of non-invasive respiratory support therapy in the hospital ward, usually indicated to let the patient have breakfast, lunch and dinner once the first acute phase with 24-72 hours of uninterrupted NIV is overcame. Alveolar collapse is another adverse event of hyperoxygenation but neither was detected in our patient.\\u003c/p\\u003e\\n\\u003cp\\u003eMental status of candidates to receive NIV may varies from wide awake to the unconsciousness. In the last group re-breathing and bronchoaspiration can appear. Parenteral treatment and nutrition is recommended to avoid bronchoaspiration. In patients with conscious preserved, maintaining intravenous treatment is not mandatory, but advisable, complemented with liquid diet and might keep tight surveillance of hypercapnia. Re-breathing occurs if the patient breathes in his own previously exhaled air with a high carbonic concentration. This would take place if the circuit does not have a release valve where the expired air can escape or if the arrangement of the system eases its recirculation. In the ADM prototype, the release valve is placed at the top of the mask, where the air flow will exit through the high-efficiency electrostatic filter and the PEEP valve. The location of an anti-return membrane in the outside-in direction is directed to avoid the recirculation of the exhaled air inside the ADM, permitting the high flow oxygen to penetrate into the mask. This way, we will prevent the patient exhaled air from drifting back to the oxygen connection. Thereby, the continuous flow of oxygen will ease the upward direction of the circulating air inside the mask, finally leaving through the upper exhalation port. (Figure 1.C). To allow the patient normal breathing if the flow system fails, our prototype has an anti-suffocation valve to take in air from the ambient if it is necessary.\\u003c/p\\u003e\\n\\u003cp\\u003eVentilator-induced lung injury (VILI) can occur in ARDS ventilated patients. COVID-19 patients with ARSD generates a high inspiratory demand in a normally compliant lung. This high demand can generate peak inspiratory pressures greater than 25 mmHg, which can be damaging to the lung causing barotrauma (pneumomediastinum and pneumothorax), volutrauma (if higher flow is provided) and atelectrauma. Also, the presence of high peak pressures in normally compliant lungs and in a situation in which the patient has a high respiratory drive, can generate alveolar shear forces that end up generating lung injury due to the wide fluctuation of pressures between the granted and the demanded by the patient. Despite in our registry there were no Peak Pressure - PEEP\\u0026gt; 15 cmH2O, it is important to mention that the study population profile is not that expected in the patients usually subsidiary to this respiratory support. (11, 12, 13, 14)\\u003c/p\\u003e\\n\\u003cp\\u003e\\u003cbr /\\u003e A limiting factor in the use of PEEP autonomous devices is the need of a high flow oxygen supply through a flowmeter that supplies more than 15 lpm). This is due because with a lower flow, a sufficient pressure is not reached for the autonomous PEEP valve to be functional. It is estimated that for the continuous treatment for 4 hours, a 50-liter cylinder of liquid oxygen would be consumed. In a hospital with access to a wall-mounted oxygen output, this is not a problem. However, in circumstances of scarce resources or in developing countries this can limit the use of this devices. Nowadays our prototype has not solved this problem but our team is working on it.\\u003c/p\\u003e\"},{\"header\":\"Conclusions\",\"content\":\"\\u003cp\\u003eWe must remind that the respiratory support of choice in patients with ARDS is invasive mechanical ventilation with OTI. This is not different in COVID patients. However, in a situation of global health crisis, the shortage of resources and hospitals with overflowing ICUs, respiratory support with NIV is mandatory pending the patient's own favorable evolution or the possibility of admission to the ICU later on [16, 17, 18]. In places without access to first level health resources, the possibility of having autonomous respiratory support devices becomes more necessary as could help many of these patients [19] Our aim is not to validate a prototype to use in normal circumstances, but to validate the safety of the clinical use of our ADM as an alternative to other CPAP devices, at exceptional times and in a context of shortages of other homologated devices. This prototype does not require electronic equipment and also due to the characteristics of the materials with which it has been made, it is fully reusable after sterilization. This provides added value for exports to developing countries, in which the existences of autonomous and reusable devices can bring hope to patients who do not even have an option to be admitted to an ICU [20, 21].\\u003c/p\\u003e\"},{\"header\":\"Declarations\",\"content\":\"\\u003cp\\u003e\\u003cstrong\\u003eEthics approval\\u003c/strong\\u003e\\u003c/p\\u003e\\n\\u003cp\\u003eThe study has been developed after the sign of the informed consent of the healthy volunteers and approval of pertinent authorities\\u003c/p\\u003e\\n\\u003cp\\u003e\\u003cstrong\\u003eConsent to participate\\u003c/strong\\u003e\\u003c/p\\u003e\\n\\u003cp\\u003eThe study has been developed after approval of pertinent authorities\\u003c/p\\u003e\\n\\u003cp\\u003e\\u003cstrong\\u003eConsent for publication\\u003c/strong\\u003e\\u003c/p\\u003e\\n\\u003cp\\u003eNot Applicable\\u003c/p\\u003e\\n\\u003cp\\u003e\\u003cstrong\\u003eAvailability of data and material\\u003c/strong\\u003e\\u003c/p\\u003e\\n\\u003cp\\u003eAll data collected is available under request\\u003c/p\\u003e\\n\\u003cp\\u003e\\u003cstrong\\u003eConflicts of interest/Competing interests\\u003c/strong\\u003e\\u003c/p\\u003e\\n\\u003cp\\u003eThe authors declare no conflicts of interests\\u003c/p\\u003e\\n\\u003cp\\u003e\\u003cstrong\\u003eFunding\\u003c/strong\\u003e\\u003c/p\\u003e\\n\\u003cp\\u003eThe study was financed and carried out thanks to Banco Santander and the assignment of its staff and facilities.Decathlon Spain gave the Easybreath masks to carry out the entire project.The design and study of materials for the parts adapted for the prototype was carried out by AIRBUS and CT engineers Printed pieces used were thanks to CSIC (ICTP-CSIC)\\u003c/p\\u003e\\n\\u003cp\\u003e\\u003cstrong\\u003eAuthors' contributions\\u003c/strong\\u003e\\u003c/p\\u003e\\n\\u003cp\\u003eBA analysed and interpreted the patients data. CC collected the data. AC helped to review the bibliography. MJB. Supervised the manuscript. AA facilitated the machines to collect the data; JMM facilitate the installations to carry out the tests and supervise them, RL coordinated the tests.\\u003c/p\\u003e\\n\\u003cp\\u003e\\u003cstrong\\u003eAcknoledgements\\u003c/strong\\u003e\\u003c/p\\u003e\\n\\u003cp\\u003eThe study was financed and carried out thanks to Banco Santander and the assignment of its staff and facilities.Decathlon Spain gave the Easybreath masks to carry out the entire project.The design and study of materials for the parts adapted for the prototype was carried out by AIRBUS (Juan Manuel Canalejo) and CT engineers (Alberto Molina)Printed pieces used were thanks to Juan Rodriguez Hern\\u0026aacute;ndez of the CSIC (ICTP-CSIC)Thanks to Angel Manuel Sevillano for the review of the papper.\\u003c/p\\u003e\"},{\"header\":\"Abbreviations\",\"content\":\"\\u003cp\\u003e\\u003cstrong\\u003eADM\\u003c/strong\\u003e - adapted diving mask\\u003c/p\\u003e\\n\\u003cp\\u003e\\u003cstrong\\u003eARDS\\u003c/strong\\u003e - acute respiratory distress\\u003c/p\\u003e\\n\\u003cp\\u003e\\u003cstrong\\u003eBMI\\u003c/strong\\u003e - body mass index\\u003c/p\\u003e\\n\\u003cp\\u003e\\u003cstrong\\u003eCO2\\u003c/strong\\u003e - carbon dioxide\\u003c/p\\u003e\\n\\u003cp\\u003e\\u003cstrong\\u003eCOVID-19\\u003c/strong\\u003e \\u0026ndash; Coronavirus infectious disease\\u003c/p\\u003e\\n\\u003cp\\u003e\\u003cstrong\\u003eCPAP\\u003c/strong\\u003e - continous positive airways pressure\\u003c/p\\u003e\\n\\u003cp\\u003e\\u003cstrong\\u003eICU\\u003c/strong\\u003e - intensive care units\\u003c/p\\u003e\\n\\u003cp\\u003e\\u003cstrong\\u003eNIV\\u003c/strong\\u003e - non-invasive ventilation\\u003c/p\\u003e\\n\\u003cp\\u003e\\u003cstrong\\u003eO2\\u003c/strong\\u003e - oxygen\\u003c/p\\u003e\\n\\u003cp\\u003e\\u003cstrong\\u003eOTI\\u003c/strong\\u003e -orotracheal intubation\\u003c/p\\u003e\\n\\u003cp\\u003e\\u003cstrong\\u003ePEEP\\u003c/strong\\u003e - positive pressure at the end of expiration\\u003c/p\\u003e\\n\\u003cp\\u003e\\u003cstrong\\u003eSLA\\u003c/strong\\u003e - stereolithography\\u003c/p\\u003e\\n\\u003cp\\u003e\\u003cstrong\\u003eVILI\\u003c/strong\\u003e - Ventilator-induced lung injury\\u003c/p\\u003e\\n\\u003cp\\u003e\\u003cstrong\\u003eWHO - \\u003c/strong\\u003eWorld Health Organization\\u003c/p\\u003e\"},{\"header\":\"References\",\"content\":\"\\u003col\\u003e\\n\\u003cli\\u003eMinisterio de Sanidad. Espa\\u0026ntilde;a. Informe n\\u0026ordm; 31. Situaci\\u0026oacute;n de COVID-19 en Espa\\u0026ntilde;a a 14 de mayo de 2020. Equipo COVID-19. RENAVE. CNE. CNM (ISCIII) https://www.mscbs.gob.es/\\u003c/li\\u003e\\n\\u003cli\\u003eWorld Health Organization. Coronavirus disease (COVID-19) outbreak. Available in: https://www.who.int\\u003c/li\\u003e\\n\\u003cli\\u003eChaomin Wu, MD; Xiaoyan Chen, MD; Yanping Cai, MD; Jia\\u0026rsquo;an Xia, MD; Xing Zhou, MD; Sha Xu, MD; Risk Factors Associated With Acute Respiratory Distress Syndrome and Death in Patients With Coronavirus Disease 2019 Pneumonia in Wuhan, China\\u003cem\\u003e JAMA Intern Med\\u003c/em\\u003e. doi:10.1001/jamainternmed.2020.0994\\u003c/li\\u003e\\n\\u003cli\\u003eBellani G, Laffey JG, Pham T, et al. Epidemiology, patterns of care, and mortality for patients with acute respiratory distress syndrome in intensive care units in 50 JAMA 2016;315:788-800.\\u003c/li\\u003e\\n\\u003cli\\u003eYang X, Yu Y, Xu J, et al. Clinical course and outcomes of critically ill patients with SARS-CoV-2 pneumonia in Wuhan, China: a single-centered, retrospective, observational Lancet Respir Med 2020. doi: 10.1016/S2213-2600(20)30079-5\\u003c/li\\u003e\\n\\u003cli\\u003eZhou F, Yu T, Du R, et al. Clinical course and risk factors for mortality of adult inpatients with COVID-19 in Wuhan, China: a retrospective cohort study. Lancet 2020:395:1054-62. doi: 10.1016/S0140-6736(20)30566-3.\\u003c/li\\u003e\\n\\u003cli\\u003eCinesi G\\u0026oacute;mez C, \\u0026Oacute;. Pe\\u0026ntilde;uelas Rodr\\u0026iacute;guez, M.l Luj\\u0026aacute;n Torn\\u0026eacute;, C. Egea Santaolalla, J.F. Masa Jim\\u0026eacute;nez, J. Garc\\u0026iacute;a Fern\\u0026aacute;ndez et al. Recomendaciones de consenso respecto al soporte respiratorio no invasivo en el paciente adulto con insuficiencia respiratoria aguda secundaria a infecci\\u0026oacute;n por SARS-CoV-2. Rev Esp Anestesiol 2020. https://doi.org/10.1016/j.redar.2020.03.006\\u003c/li\\u003e\\n\\u003cli\\u003e. Farr\\u0026eacute; R, Montserrat JM, Solana G, Gozal D, Navajas D. Easy-to-build and affordable continuous positive airway pressure CPAP device for adult patients in low-income countries. Eur Respir J. 2019;53(5).\\u003c/li\\u003e\\n\\u003cli\\u003eOlivieri C, Costa R, Conti G, Navalesi P. Bench studies evaluating devices for non-invasive ventilation: critical analysis and future perspectives. Intensive Care Med [Internet]. 2012 Jan 29;38(1):160\\u0026ndash;7. http://link.springer.com/10.1007/s00134-011-2416-9\\u003c/li\\u003e\\n\\u003cli\\u003eSimonds AK, Hanak A, Chatwin M, Morrell M, Hall A, Parker KH, et al. Evaluation of droplet dispersion during non-invasive ventilation, oxygen therapy, nebuliser treatment and chest physiotherapy in clinical practice: implications for management of pandemic influenza and other airborne infections. Health technology assessment (Winchester, England). 2010;14(46):131-72.\\u003c/li\\u003e\\n\\u003cli\\u003eCressoni M, Gotti M, Chiurazzi C, Massari D, Algieri I, Amini M, Cammaroto A, Brioni M, Montaruli C, Nikolla K, Guanziroli M, Dondossola D, Gatti S, Valerio V, Vergani GL, Pugni P, Cadringher P, Gagliano N, Gattinoni L. Mechanical power and development of ventilator-induced lung injury. Anesthesiology. 2016;124:1100 \\u0026ndash;8.\\u003c/li\\u003e\\n\\u003cli\\u003eSilva PL, Ball L, Rocco PRM, Pelosi P. Power to mechanical power to reduce ventilator induced lung injury? Intensive Care Med Exp. 2019;7(Suppl 1):38: 1\\u0026ndash;11. https://doi.org/10.1186/s40635-019-0243-4.\\u003c/li\\u003e\\n\\u003cli\\u003eTonetti T\\u003csup\\u003e1\\u003c/sup\\u003e,\\u0026nbsp;Vasques F\\u003csup\\u003e1\\u003c/sup\\u003e,\\u0026nbsp;Rapetti F\\u003csup\\u003e1\\u003c/sup\\u003e,\\u0026nbsp;Maiolo G\\u003csup\\u003e1\\u003c/sup\\u003e,\\u0026nbsp;Collino F\\u003csup\\u003e1\\u003c/sup\\u003e,\\u0026nbsp;Romitti F Driving pressure and mechanical power: new targets for\\u0026nbsp;VILI\\u0026nbsp;prevention. Ann Transl Med.2017 Jul;5(14):286. doi: 10.21037/atm.2017.07.08.\\u003c/li\\u003e\\n\\u003cli\\u003eMarini JJl. How I optimize power to avoid\\u0026nbsp;VILI. Crit Care.\\u0026nbsp;2019 Oct 21;23(1):326. doi: 10.1186/s13054-019-2638-8.\\u003c/li\\u003e\\n\\u003cli\\u003eBrugniaux JV\\u003csup\\u003e1\\u003c/sup\\u003e,\\u0026nbsp;Coombs GB\\u003csup\\u003e2\\u003c/sup\\u003e,\\u0026nbsp;Barak OF\\u003csup\\u003e3,4\\u003c/sup\\u003e,\\u0026nbsp;Dujic Z\\u003csup\\u003e5\\u003c/sup\\u003e,\\u0026nbsp;Sekhon MS\\u003csup\\u003e2,6\\u003c/sup\\u003e,\\u0026nbsp;Ainslie PN\\u003csup\\u003e2\\u003c/sup\\u003e. Highs and lows of\\u0026nbsp;hyperoxia: physiological, performance, and clinical aspects. Am J Physiol Regul Integr Comp Physiol.2018 Jul 1;315(1):R1-R27\\u003c/li\\u003e\\n\\u003cli\\u003eRochwerg B, Brochard L, Elliott MW, Hess D, Hill NS, Nava S, et al. Official ERS/ATS clinical practice guidelines: noninvasive ventilation for acute respiratory failure. Eur Respir J [Internet]. 2017 Aug 31;50(2):1602426. http://erj.ersjournals.com/lookup/doi/10.1183/13993003.02426-2016\\u003c/li\\u003e\\n\\u003cli\\u003eAlhazzani W, M\\u0026oslash;ller MH, Arabi YM, Loeb M, Gong MN, Fan E, Oczkowski S, Levy MM, Derde L, Dzierba A, Du B, Aboodi M, Wunsch H, Cecconi M, Koh Y, Chertow DS, Maitland K, Alshamsi F, Belley-Cote E, Greco M, Laundy M, Morgan JS, Kesecioglu J,McGeer A, Mermel L, Mammen MJ, Alexander PE, Arrington A, Centofanti JE, Citerio G, Baw B, Memish ZA, Hammond N, Hayden FG, Evans L, Rhodes A. Surviving Sepsis Campaign: Guidelines on the Management of Critically Ill Adults with Coronavirus Disease 2019 (COVID-19\\u003cstrong\\u003e).\\u003c/strong\\u003e Crit Care Med. 2020 Mar 27. doi: 10.1097/CCM.0000000000004363.\\u003c/li\\u003e\\n\\u003cli\\u003eJi Y, Ma Z, Peppelenbosch MP, Pan Q. Potential association between COVID-19 mortality and healthcare resource availability. Lancet Glob Health. 2020, http://dx.doi.org/10.1016/S2214-109X(20)30068-1.\\u003c/li\\u003e\\n\\u003cli\\u003eTruog RD, Mitchell C, Daley CQ. The Toughest Triage \\u0026mdash; Allocating Ventilators in a Pandemic. New Eng J Med, in press. DOI: 10.1056/NEJMp2005689.\\u003c/li\\u003e\\n\\u003cli\\u003eMurthy S, Leligdowicz A, Adhikari NKJ. Intensive Care Unit Capacity in Low-Income Countries: A Systematic Review. Azevedo LCP, editor. PLoS One [Internet]. 2015 Jan 24;10(1): e0116949. http://dx.plos.org/10.1371/journal.pone.0116949\\u003c/li\\u003e\\n\\u003cli\\u003eMandelzweig K, Leligdowicz A, Murthy S, Lalitha R, Fowler RA, Adhikari NKJ. Non-invasive ventilation in children and adults in low- and low-middle income countries: A systematic review and meta-analysis. J Crit Care [Internet]. 2018 Oct;47:310\\u0026ndash;9. https://linkinghub.elsevier.com/retrieve/pii/S0883944117302472\\u003c/li\\u003e\\n\\u003c/ol\\u003e\"},{\"header\":\"Tables\",\"content\":\"\\u003cp\\u003e\\u003cstrong\\u003eTable 1\\u003c/strong\\u003e. Baseline arterial blood gases (ABG) Values and Previous Withdrawal of ADM\\u003c/p\\u003e\\n\\u003ctable border=\\\"1\\\"\\u003e\\n\\u003ctbody\\u003e\\n\\u003ctr\\u003e\\n\\u003ctd width=\\\"132\\\"\\u003e\\n\\u003cp\\u003e\\u0026nbsp;\\u003c/p\\u003e\\n\\u003c/td\\u003e\\n\\u003ctd width=\\\"47\\\"\\u003e\\n\\u003cp\\u003e\\u003cstrong\\u003epH\\u003c/strong\\u003e\\u003c/p\\u003e\\n\\u003c/td\\u003e\\n\\u003ctd width=\\\"66\\\"\\u003e\\n\\u003cp\\u003e\\u003cstrong\\u003epCO2 (\\u003c/strong\\u003emmHg\\u003cstrong\\u003e)\\u003c/strong\\u003e\\u003c/p\\u003e\\n\\u003c/td\\u003e\\n\\u003ctd width=\\\"57\\\"\\u003e\\n\\u003cp\\u003e\\u003cstrong\\u003epO2 (\\u003c/strong\\u003emmHg\\u003cstrong\\u003e)\\u003c/strong\\u003e\\u003c/p\\u003e\\n\\u003c/td\\u003e\\n\\u003ctd width=\\\"76\\\"\\u003e\\n\\u003cp\\u003e\\u003cstrong\\u003eHCO3\\u003c/strong\\u003e\\u003c/p\\u003e\\n\\u003cp\\u003e\\u003cstrong\\u003e(\\u003c/strong\\u003emmHg\\u003cstrong\\u003e)\\u003c/strong\\u003e\\u003c/p\\u003e\\n\\u003c/td\\u003e\\n\\u003ctd width=\\\"57\\\"\\u003e\\n\\u003cp\\u003e\\u003cstrong\\u003estO2\\u003c/strong\\u003e\\u003c/p\\u003e\\n\\u003cp\\u003e\\u003cstrong\\u003e(%)\\u003c/strong\\u003e\\u003c/p\\u003e\\n\\u003c/td\\u003e\\n\\u003c/tr\\u003e\\n\\u003ctr\\u003e\\n\\u003ctd width=\\\"132\\\"\\u003e\\n\\u003cp\\u003e\\u003cstrong\\u003eBaseline ABG \\u003c/strong\\u003e\\u003c/p\\u003e\\n\\u003c/td\\u003e\\n\\u003ctd width=\\\"47\\\"\\u003e\\n\\u003cp\\u003e7,42\\u003c/p\\u003e\\n\\u003c/td\\u003e\\n\\u003ctd width=\\\"66\\\"\\u003e\\n\\u003cp\\u003e38,43\\u003c/p\\u003e\\n\\u003c/td\\u003e\\n\\u003ctd width=\\\"57\\\"\\u003e\\n\\u003cp\\u003e91,68\\u003c/p\\u003e\\n\\u003c/td\\u003e\\n\\u003ctd width=\\\"76\\\"\\u003e\\n\\u003cp\\u003e25,26\\u003c/p\\u003e\\n\\u003c/td\\u003e\\n\\u003ctd width=\\\"57\\\"\\u003e\\n\\u003cp\\u003e96,75\\u003c/p\\u003e\\n\\u003c/td\\u003e\\n\\u003c/tr\\u003e\\n\\u003ctr\\u003e\\n\\u003ctd width=\\\"132\\\"\\u003e\\n\\u003cp\\u003e\\u003cstrong\\u003eABG with ADM\\u003c/strong\\u003e\\u003c/p\\u003e\\n\\u003c/td\\u003e\\n\\u003ctd width=\\\"47\\\"\\u003e\\n\\u003cp\\u003e7,42\\u003c/p\\u003e\\n\\u003c/td\\u003e\\n\\u003ctd width=\\\"66\\\"\\u003e\\n\\u003cp\\u003e41,22\\u003c/p\\u003e\\n\\u003c/td\\u003e\\n\\u003ctd width=\\\"57\\\"\\u003e\\n\\u003cp\\u003e520,99\\u003c/p\\u003e\\n\\u003c/td\\u003e\\n\\u003ctd width=\\\"76\\\"\\u003e\\n\\u003cp\\u003e26,97\\u003c/p\\u003e\\n\\u003c/td\\u003e\\n\\u003ctd width=\\\"57\\\"\\u003e\\n\\u003cp\\u003e99,94\\u003c/p\\u003e\\n\\u003c/td\\u003e\\n\\u003c/tr\\u003e\\n\\u003ctr\\u003e\\n\\u003ctd width=\\\"132\\\"\\u003e\\n\\u003cp\\u003e\\u003cstrong\\u003eP\\u003c/strong\\u003e\\u003c/p\\u003e\\n\\u003c/td\\u003e\\n\\u003ctd width=\\\"47\\\"\\u003e\\n\\u003cp\\u003e0,63\\u003c/p\\u003e\\n\\u003c/td\\u003e\\n\\u003ctd width=\\\"66\\\"\\u003e\\n\\u003cp\\u003e\\u003cstrong\\u003e0,51\\u003c/strong\\u003e\\u003c/p\\u003e\\n\\u003c/td\\u003e\\n\\u003ctd width=\\\"57\\\"\\u003e\\n\\u003cp\\u003e\\u003cstrong\\u003e0,00\\u003c/strong\\u003e\\u003c/p\\u003e\\n\\u003c/td\\u003e\\n\\u003ctd width=\\\"76\\\"\\u003e\\n\\u003cp\\u003e\\u003cstrong\\u003e0,51\\u003c/strong\\u003e\\u003c/p\\u003e\\n\\u003c/td\\u003e\\n\\u003ctd width=\\\"57\\\"\\u003e\\n\\u003cp\\u003e0,98\\u003c/p\\u003e\\n\\u003c/td\\u003e\\n\\u003c/tr\\u003e\\n\\u003c/tbody\\u003e\\n\\u003c/table\\u003e \"}],\"fulltextSource\":\"\",\"fullText\":\"\",\"funders\":[],\"hasAdminPriorityOnWorkflow\":false,\"hasManuscriptDocX\":true,\"hasOptedInToPreprint\":true,\"hasPassedJournalQc\":\"\",\"hasAnyPriority\":false,\"hideJournal\":true,\"highlight\":\"\",\"institution\":\"\",\"isAcceptedByJournal\":false,\"isAuthorSuppliedPdf\":false,\"isDeskRejected\":\"\",\"isHiddenFromSearch\":false,\"isInQc\":false,\"isInWorkflow\":false,\"isPdf\":false,\"isPdfUpToDate\":true,\"isWithdrawnOrRetracted\":false,\"journal\":{\"display\":true,\"email\":\"info@researchsquare.com\",\"identity\":\"researchsquare\",\"isNatureJournal\":false,\"hasQc\":true,\"allowDirectSubmit\":true,\"externalIdentity\":\"\",\"sideBox\":\"\",\"snPcode\":\"\",\"submissionUrl\":\"/submission\",\"title\":\"Research Square\",\"twitterHandle\":\"researchsquare\",\"acdcEnabled\":true,\"dfaEnabled\":false,\"editorialSystem\":\"\",\"reportingPortfolio\":\"\",\"inReviewEnabled\":false,\"inReviewRevisionsEnabled\":true},\"keywords\":\"non-invasive ventilation, COVID, non-electrical device, mask, high flow oxygen\",\"lastPublishedDoi\":\"10.21203/rs.3.rs-73598/v1\",\"lastPublishedDoiUrl\":\"https://doi.org/10.21203/rs.3.rs-73598/v1\",\"license\":{\"name\":\"CC BY 4.0\",\"url\":\"https://creativecommons.org/licenses/by/4.0/\"},\"manuscriptAbstract\":\"\\u003cp\\u003ePurpose\\u003c/p\\u003e\\u003cp\\u003eThe scenario of global health crisis due to SARS-CoV-2 pandemia combined with the shortage of resources in many countries has justified numerous studies to design easily replicable and economic respiratory support devices. We have developed an adapted diving mask (ADM) to be used as an autonomous and safe respiratory support. The objective was to prove a minimum positive end expiratory pressure (PEEP) with the ADM without any adverse events.\\u003c/p\\u003e\\u003cp\\u003eMethods\\u003c/p\\u003e\\u003cp\\u003eBench tests was done in 22 healthy volunteers with our ADM prototype. Expiratory-inspiratory flow and pressure were registered apart from blood and transcutaneous hypercapnia.\\u003c/p\\u003e\\u003cp\\u003eResults\\u003c/p\\u003e\\u003cp\\u003eThere were no statistically significant differences in the baseline analysis results and after therapy, except in pO2. Mean PEEP measured was 8.2 ± 4.2 cmH2O with a peak measured pressure of 20\\u0026nbsp;cm H2O.\\u003c/p\\u003e\\u003cp\\u003eConclussions\\u003c/p\\u003e\\u003cp\\u003eThe ADM has shown good tolerance and a therapeutic manteining PEEP with no evidence of any deletereous effect or hypercapnia with its continuous use.\\u003c/p\\u003e\",\"manuscriptTitle\":\"Adapted Diving Mask Bench Tests as an Autonomous Respiratory Support in Healthy Volunteer\",\"msid\":\"\",\"msnumber\":\"\",\"nonDraftVersions\":[{\"code\":1,\"date\":\"2020-09-22 16:47:37\",\"doi\":\"10.21203/rs.3.rs-73598/v1\",\"editorialEvents\":[{\"type\":\"communityComments\",\"content\":0}],\"status\":\"published\",\"journal\":{\"display\":true,\"email\":\"info@researchsquare.com\",\"identity\":\"researchsquare\",\"isNatureJournal\":false,\"hasQc\":true,\"allowDirectSubmit\":true,\"externalIdentity\":\"\",\"sideBox\":\"\",\"snPcode\":\"\",\"submissionUrl\":\"/submission\",\"title\":\"Research Square\",\"twitterHandle\":\"researchsquare\",\"acdcEnabled\":true,\"dfaEnabled\":false,\"editorialSystem\":\"\",\"reportingPortfolio\":\"\",\"inReviewEnabled\":false,\"inReviewRevisionsEnabled\":true}}],\"origin\":\"\",\"ownerIdentity\":\"34c7445d-5b4f-4fa8-af12-59f90b09efdf\",\"owner\":[],\"postedDate\":\"September 22nd, 2020\",\"published\":true,\"recentEditorialEvents\":[],\"rejectedJournal\":[],\"revision\":\"\",\"amendment\":\"\",\"status\":\"posted\",\"subjectAreas\":[{\"id\":562829,\"name\":\"Pulmonology\"},{\"id\":562830,\"name\":\"Anesthesiology \\u0026 Pain Medicine\"}],\"tags\":[],\"updatedAt\":\"2020-11-20T16:02:06+00:00\",\"versionOfRecord\":[],\"versionCreatedAt\":\"2020-09-22 16:47:37\",\"video\":\"\",\"vorDoi\":\"\",\"vorDoiUrl\":\"\",\"workflowStages\":[]},\"version\":\"v1\",\"identity\":\"rs-73598\",\"journalConfig\":\"researchsquare\"},\"__N_SSP\":true},\"page\":\"/article/[identity]/[[...version]]\",\"query\":{\"redirect\":\"/article/rs-73598\",\"identity\":\"rs-73598\",\"version\":[\"v1\"]},\"buildId\":\"rHA-KDH7Qsr4HCuvH75dn\",\"isFallback\":false,\"isExperimentalCompile\":false,\"dynamicIds\":[84888],\"gssp\":true,\"scriptLoader\":[]}","source_license":"CC-BY-4.0","license_restricted":false}