Effect of intravenous esketamine on oxygenation and intrapulmonary shunting during One-lung ventilation in thoracoscopic surgery: A Randomized Controlled Trial

Effect of intravenous esketamine on oxygenation and intrapulmonary shunting during One-lung ventilation in thoracoscopic surgery: A Randomized Controlled Trial | 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 Article Effect of intravenous esketamine on oxygenation and intrapulmonary shunting during One-lung ventilation in thoracoscopic surgery: A Randomized Controlled Trial Fu Chunyan, Han Xiaodi, Shen Kemeng, Jing Liu, Zheng Xiaozhen This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-7593019/v1 This work is licensed under a CC BY 4.0 License Status: Under Review Version 1 posted 9 You are reading this latest preprint version Abstract Background： One-lung ventilation (OLV) is a commonly used mechanical ventilation technique in open chest surgery, which can lead to serious complications.This study aims to investigate the effects of esketamine on oxygenation (PaO₂/FiO₂) and intrapulmonary shunt (Qs/Qt) during OLV in patients undergoing thoracic surgery. Methods： Fifty patients were randomly allocated to either esketamine group (group E) or control group (group C).Group E received 0.5 mg/kg esketamine.The control group received normal saline. blood samples were takento analyze arterial blood gasses during four time periods at bfore anesthesia induction (T0),30 min after OLV(T1),60 min after OLV(T2) and 20 min after reinstitution of two-lung ventilation(T3).PaO₂/FiO₂, Qs/Qt , heart rate, mean arterial pressure(MAP),parameters mechanics and postoperative pulmonary complication incidence values were recorded at these time points. Results: Compared with the group C, the PaO2/FiO2 ratio was significantly increased, and the Qs/Qt were significantly decreased in the group E at T1, T2, and T3 (all p<0.05).At T1 and T2, the Ppeak and Pplat in the group E were significantly lower than those in the group C, while the Cdyn value was significantly higher than that in the group C (all P < 0.05).The incidence of atelectasis in the group E was significantly lower than that in the group C (16% vs. 32%, P=0.002). However, there was no statistically significant difference in the incidence of any other PPCs episodes between the two groups. Conclusion： Intravenous administration of esketamine during lung resection improves oxygenation status (PaO₂/FiO₂), reduces pulmonary artery shunt fraction (Qs/Qt), enhances pulmonary artery compliance (Cdyn), and decreases the incidence of postoperative pulmonary complications. Trial registration： The trial was registered at the Chinese Clinical Trials Registry (www.chictr.org.cn, registration number: ChiCTR2400093592, date of registration: 09/12/2024). One-lung ventilation Esketamine Oxygenation Pulmonary shunt Figures Figure 1 Figure 2 Figure 3 Introduction One-lung ventilation (OLV) is extensively utilized in video-assisted thoracoscopic surgery (VATS), owing to its capacity to expand the surgical visual field, achieve effective isolation of the lungs, and minimize cross-infection between the two lungs[ 1 , 2 ].However, during one-lung ventilation (OLV), the body relies on one lung for oxygenation, resulting in ventilation/perfusion (V/Q) imbalance, which increases intrapulmonary shunting and thereby increases the risk of hypoxemia in patients[4,5].Hypoxic pulmonary vasoconstriction (HPV) is an intrinsic homeostatic mechanism of the pulmonary vascular system that optimizes ventilation-perfusion matching by redirecting pulmonary blood flow to highly oxygenated lung segments [ 3 ]. It is an important protective mechanism for maintaining arterial oxygenation during OLV.In the anesthesia management of OLV patients, it is important to administer drugs that have no inhibitory effect or minimal inhibitory effect on this mechanism. Esketamine is an N-methyl-D-aspartate (NMDA) receptor antagonist with sedative and analgesic effects.It has been reported that esketamine can block L-type calcium channels, relax bronchial smooth muscle, increase lung compliance, and increase minute ventilation [ 11 , 12 ].Intravenous infusion of esketamine can improve static lung compliance (Cst) and PaO₂/FiO₂ ratio in mechanically ventilated ARDS patients[ 7 ].In addition, as an analgesic, esketamine can also reduce opioid consumption and significantly relieve postoperative pain [ 6 ].However, the effects of intravenous esketamine on intraoperative oxygenation and intrapulmonary shunting in patients undergoing one-lung ventilation remain unknown. Therefore, this study aims to investigate the effects of intraoperative intravenous administration of esketamine on intraoperative oxygenation and intrapulmonary shunting in patients undergoing one-lung ventilation. We hypothesize that intravenous administration of esketamine may reduce intraoperative arterial oxygenation (PaO₂/FiO₂) and decrease pulmonary shunting in patients undergoing one-lung ventilation. Materials and methods Study Design and Ethics This study was designed as a prospective, randomized,parallel-controlled trial.The protocol was approved by the Ethics Committee of the First Affiliated Hospital of Henan University (2024-03-070) and was registered at the Chinese Clinical Trial Registry(ChiCTR2400093592).This report adheres to the CONSORT guidelines. The study was conducted according to the guidelines of the Declaration of Helsinki with Good Clinical Practice. All participants provided written informed consent before enrolment. Study Population Fifty patients who underwent elective thoracoscopic lobectomy.All patients were ASA I-II, aged 18-65years, and their body mass index was 18–30 kg/m 2 . According to the eighth edition of staging standard of International Association for Lung Cancer Research (IASLC), all the selected lung cancer patients were in stage IA. Exclusion criteria were as follows:(1)Patients diagnosed with severe hypertension or cardiac conduction block (second- or third-degree atrioventricular block, bundle branch block);(2) The patient has a history of thoracic surgery.(3) Patients with liver parenchymal damage (ALT or AST > 2×normal value), Child-Pugh C-class cirrhosis, or renal failure (SCr > 177 µmol /l);(4) Patients addicted to opiate drugs or sedative-hypnotic drugs;(5) Patients who are allergic to esketamine and other commonly used anesthetics;(6) Patients with mental disorders and those who are unable to cooperate. Patients who require conversion to open-chest surgery during the procedure, single-lung ventilation for > 4 hours, or transfer to the intensive care unit (ICU) for further treatment after surgery will be withdrawn from the study. Patient grouping and randomization Using SPSS 25.0 (IBM Corp., Armonk, NY, USA) and computer-generated sequences, patients were randomly assigned in a 1:1 ratio to the esketamine group (E group) or the control group (C group).Randomized grouping envelopes contain grouping information, and nurses prepare study medications according to group assignments.Dilute the esketamine group with 50 mL of saline to a concentration of 1 mg/mL.The control group was prepared with an equal volume of saline solution.Both groups received the prepared medication using syringes that looked the same.Patients, clinicians, and outcome assessors remained blinded throughout the study period. Intervention Patients in group esketamine received a bolus of esketamine 0.5mg/kg before the induction of anesthesia, then followed by a continuous infusion of 0.15 mg/kg/h intraoperatively until the end of surgery. Patients in group control received 0.9% saline in place of lidocaine at the same time points. Anesthesia Protocol All patients underwent standard preoperative preparation, which included a fasting period of 8 h and fluid restriction for 2 h prior to the procedure. No preoperative medications were administered.Upon admission to the room, the patient's ECG, NBP, SpO₂, and BIS (Aspect Medical Systems, Newton, MA, USA) are monitored.Under local anesthesia, radial artery puncture and catheterization were performed for invasive blood pressure monitoring and arterial blood gas analysis (GEM Premier 4000, Instrumentation Laboratory, Lexington, MA, USA). Anesthesia was induced with esketamine 0.5mg/kg (or the same volume of 0.9% saline),propofol 0.5-1 mg/kg,sufentanil 0.4 µg/kg,rocuronium 0.6 mg/kg.The esketamine or 0.9% saline infusion was initiated after induction and dosed as described above.Anesthesia was maintained by remifentanil 0.1–0.2µg /kg/ min and propofol, combined with sevoflurane 1%.Maintain the BIS values between 40 and 60 by adjusting the dose of propofol.All patients underwent tracheal intubation using a double-lumen catheter (Broncho-Cath, Mallinckrodt, Dublin, Ireland) following induction of anesthesia.The position of the catheter was adjusted under a fiber-optic bronchoscope and connected to the anesthesia machine (Primus iventilator, Drager TM Medical,Lubeck,Germany)for volume-controlled mechanical ventilation.Mechanical ventilation parameters are set as follows[ 8 ]:during double-lung ventilation, tidal volume (VT) 6–8 mL/kg, during one-lung ventilation, VT 5–6 mL/kg, frequency (f) 12–15 times/min, PEEP 5cmH2O, I : E = 1 : 2, FIO2 = 1:0, and PETCO2 maintained in the range of 35-45mmHg.Mean arterial pressure was maintained within ± 20% of the baseline.Hypotension was treated with norepinephrine 4µg or ephedrine 5mg; episodes of hypertension were managed by increasing the propofol or remifentanil infusion rate.If hypertension persisted despite sufficient analgesia and depth of anesthesia, intravenous bolus of urapidil was given.At the conclusion of surgery, discontinue all medications, neuromuscular block was reversed and extubation was attempted in the operating theatre .Patients who did not meet extubation criteria were transferred to the post-anesthesia care unit (PACU). Postoperative patient-controlled intravenous analgesia (PCA) was performed with drug formulations (sufentanil 2µg/kg, Ondansetron 16 mg, 0.9% saline diluted to 100 mL) using a set lock time of 15 min, a background infusion dos-e to 2 mL/h, and the PCA was set at 0.5 mL/times to maintain the visual analogue scale (VAS) below or equal to 3 points.Discharge to the surgical wards when Aldrete scores of greater than or equal to 8 out of 10 were achieved. Observational indexes The primary outcome was lung oxygenation(PaO2/FIO2 ) and the pulmonary shunt fraction (Qs/Qt).The secondary outcomes included: (1) parameters reflecting mechanics༚ Peak airway pressure(Ppeak)、Airway Platform Pressure༈Pplat༉、dynamic lung compliance(Cdyn = Vt/(Pmax-PEEP)); (2) hemodynamics (heart rate and mean arterial pressure);༈3༉Incidence of Postoperative Pulmonary Complications (PPCs).PPCs is defined as the presence of at least one of the following: decreased saturation (defined as SpO 2 < 90% in room air), clinical signs and symptoms (including respiratory infection, respiratory failure, and bronchospasm), and abnormal chest X-ray findings (including pleural effusion, atelectasis, pneumothorax, aspiration pneumonia, and pulmonary edema)[ 14 ]. Data Collection The day before the operation, the patient’s baseline characteristics were recorded.The heart rate (HR) and mean arterial pressure(MAP) were were measured bfore anesthesia induction (T0),30 min after OLV(T1),60 min after OLV(T2) and 20 min after reinstitution of two-lung ventilation(T3),and collect 1 milliliter of blood from the radial artery for arterial blood gas analysis, calculating the lung oxygenation(PaO2/FIO2 ),the pulmonary shunt fraction (Qs/Qt).Pulmonary shunt fraction (Qs/Qt) was calculated using the following formula: Qs/Qt= (CcO2 − CaO2)/(CcO2 − CvO2). Whereby CaO2(oxygen content of arterial blood) = (PaO2×0.0031) + (Hb × 1.34 × SaO2). CvO2(oxygen content of venous blood) = (PvO2× 0.0031) +(Hb × 1.34 × SvO2). CcO2= ([FiO2× (PB − pH2O) − (PaCO2/RQ)] ×0.0031) + (Hb × 1.34). PB –Barometric pressure (760 mmHg), pH2O–47 mmHg, Hb –Hemoglobin, RQ –Respiratory quotient (0.8). Statistics Sample size calculations were performed using PASS software (Version 11.0.7, NCS, LCC, Kaysville, UT, USA).The primary outcome was lung oxygenation expressed by PaO2/FIO2 ratio during OLV,preliminary study results indicated an oxygenation index of 192 ± 67 mmHg at OLV 60 min,The difference in PaO₂/FiO₂ ratios between the two groups was 50 mmHg and was statistically significant,With a bilateral α of 0.05 and a power of 90%,the sample size was calculated as N1 = N2 = 25 for each group. Our study finally included a total of 50 patients. The SPSS 23.0 software package (IBM Corporation,Armonk, NY, USA) was used for statistical analysis. Categorical data were expressed as frequencies or percentages and analyzed using the chi-square (χ2) test or Fisher’s exact test. The Kolmogorov-Smirnov test was used to assess the normality of continuous variables. Normally distributed continuous variables were presented as the mean ± standard deviation (SD), and compared between groups using the independent samples t-test. For nonnormally distributed quantitative variables, data were expressed as median (interquartile range [IQR]), and comparisons were made using the Mann-Whitney U test.Analysis of variance (ANOVA) was used to compare different time points within groups. A p-value of less than 0.05 was considered statistically significant. Results Seventy patients were determined to be eligible for this study, but nine patients were excluded at initial screening . Of the 61 patients, 11 were excluded from the study because of incomplete data and/or changes of surgical plan. Data from 25 patients in each group were analysed (Fig. 1).There were no differences between groups regarding baseline characteristics(Table 1). At T0, there were no statistically significant differences between the two groups in PaO₂/FiO₂ and Qs/Qt ( P > 0.05) .Compared with T0, PaO 2 /FiO 2 were lower in groups E and C at T1 to T3, while Qs/Qt significantly increased.( P < 0.05)（Fig.2）.Compared with group C,PaO2/FiO2 were higher and Qs/Qt were lower in group E at the T1、T2 and T3 time points (P < 0.05) (Fig. 2). Compared with group C,Ppeak and Pplat were lower and Cdyn were higher in group E at the T2 and T3 time points (P 0.05) (Table 2). There was no statistically significant difference in hemodynamic parameters (MAP, HR) between the two groups at T0-T4 ( P > 0.05)（Fig 3）.Compared with group C, fewer patients in group E required vasopressors during surgery (8% vs. 24%, P < 0.001）（Table 3）. The total intraoperative consumption of remifentanil and propofol, as well as the postoperative consumption of sufentanil in group E was less than that in group C (P < 0.05) (Table 3). The incidence of atelectasis in group E was 16% (4/25), significantly lower than the 32% (8/25) observed in group C ( P 0.05).The postoperative hospital stay in group E was shorter than that in group C (7.76 ± 1.35 vs. 8.45 ± 1.66, P = 0.045)（Table 4）. Table 1 Demographic and Intraoperative Characteristics Esketamine (n = 25) Control (n = 25) P value Age (years) 56.15 ± 9.57 56.58 ± 9.53 0.832 Sex (M/F) 15/10 13/12 0.366 BMI (kgm 2 ) 24.6 ± 4.0 22.3 ± 5.7 0.276 ASA rating(Ⅰ/II) 3/22 4/21 0.702 Hypertension 9（36%） 8（32%） 0.794 Smoking history (no/current) 19/6 20/5 0.746 Preoperative spirometry FEV1, % predicted FVC, % predicted FEV1/FVC, % 82 ± 18 81 ± 17 0.734 85 ± 16 86 ± 14 0.930 82 ± 13 80 ± 12 0.973 PH 7.41 ± 0.02 7.40 ± 0.03 0.978 Hb(mg l −1 ) 118.3 ± 12.5 118.8 ± 11.9 0.934 Preoperative LVEF (%) 64.72 ± 4.11 65.45 ± 4.74 0.374 Operation time (min) 180.7 ± 38.9 183.3 ± 41.5 0.857 OLV time (min) 114.4 ± 32.3 118.1 ± 34.4 0.842 Fluid intake (ml) 790.16±80.47 798.44±78.62 0.247 Estimated blood loss (ml) 112.52±45.32 116.46±50.21 0.694 Urine volume (mL) 263.74±105.63 270.83±110.44 0.396 Right/left lobectomy Right upper lobe Right middle lobe Right lower lobe Left upper lobe Left lower lobe 11/14 10/15 0.999 6（24%） 8（32%） 5（20%） 2（8%） 2（8%） 4（16%） 8（32%） 6（24%） 4（16%） 5（20%） Data are presented as number of patients or mean ± standard deviation, number or percentage of patients. ASA, American Society of Anesthesiologists; FEV1, forced expiratory volume in 1 s; FVC, forced vital capacity; OLV, one-lung ventilation; LVEF%, Left Ventricular Ejection Fractions. Table 2 Haemodynamic and respiratory changes Esketamine (n = 25) Control (n = 25) P value PaCO2 (mmHg) T0 38..58 ± 4.82 38.79 ± 5.65 0.861 T1 40.10 ± 5.35 40.95 ± 5.51 0.485 T2 41.23 ± 4.41 41.83 ± 5.95 0.176 T3 42.91 ± 4.42 42.43 ± 5.12 0.643 Ppeak (cmH2O) T1 19.24±2.42 20.56±3.50 0.143 T2 20.13±3.27 22.72±3.27 0.012 T3 17.44±2.51 20.12±2.77 <0.001 Pplato (cmH2O) T1 19.24±2.42 21.56±3.50 0.135 T2 20.12±3.27 22.72±3.71 0.015 T3 17.44±2.51# 20.12±2.77# <0.001 Cdyn(mL/cmH2O) T1 31.65±10.19 30.42±8.82 0.650 T2 30.39±7.52 24.20±5.23 0.001 T3 43.48±11.16 41.46±8.00 0.466 Values expressed as mean ± standard deviation.HR: heart rate; MAP: mean arterial pressure;BIS, bispectral index; PaCO2: partial pressure of carbon dioxide partial pressure;PaO2, partial pressure of oxygen in arterial blood;T0: before one-lung ventilation; T1: 15 min after one-lung ventilation; T2: 1 h after onelung ventilation; T3: 20 min after resuming two-lung ventilation.*P < 0.05 versus T0,#P<0.05 vs. control group. Table 3 Comparison of perioperative anesthetic drug consumption Esketamine (n = 25) Control (n = 25) p value remifentanil (mg) 1.32±0.28 1.86±0.44 <0.001 sufentanil (μg) 41(36.56-41.45) 42(36.75–41.89) 0.045 propofol (mg) 298±48 430±77 <0.001 Number of patients required vasopressor 2（8%） 6（24%） <0.001 The data are presented as the means ± SD or the medians (interquartile ranges). Table 4 Postoperative outcome Esketamine (n = 25) Control (n = 25) p value Pulmonary complications Atelectasis Pneumonia Respiratory failure Pleural effusion 8（32%） 15（60%） 0.004 4（16%） 8（32%） 0.002 1（4%） 2（8%） 0.142 2（8%） 3（12%） 0.432 1（4%） 2（8%） 0.306 ARDS 0（0%） 0（0%） 1 Thoracic drainagetube removal time (days) 3.42 ± 1.31 3.36 ± 1.21 0.582 Postoperativehospital stay (d) 7.76 ± 1.35 8.45 ± 1.66 0.045 Data are mean ± SD, median [IQR] or n (%).PPC, postoperative pulmonary complication; ARDS, acute respiratory distress syndrome Discussion This randomized trial evaluated the effects of esketamine on oxygenation and Qs/Qt in patients undergoing thoracoscopic radical resection for lung cancer. The study demonstrated that continuous infusion of esketamine significantly improved arterial oxygenation (PaO₂/FiO₂) during OLV, reduced Qs/Qt, enhanced dynamic lung compliance, and resulted in fewer postoperative pulmonary complications. OLV can promote the release of oxygen free radicals and inflammatory factors, leading to oxidative stress and pulmonary inflammatory response, as well as damage to alveolar epithelial cells and vascular endothelial cells, resulting in increased pulmonary capillary permeability, alveolar and interstitial edema bleeding and inflammatory cell infiltration,ultimately leading to lung injury and worsening hypoxemia[ 9 , 10 ].PaO2/FiO2 reflects the gas exchange function of the lungs; the larger PaO2/FiO2 presents better lung ventilation function.This study found that PaO2/FiO2 ratios decreased significantly in both groups during one-lung ventilation. Compared with Group C, patients in Group E exhibited signific-antly higher PaO2/FiO2 during OLV and after transitioning back to double-lung ventilation.Esketamine can reduce perioperative lung injury in patients undergoing surgery by repressing inflammatory responses and oxidative stress to promote lung function and decrease adverse effects of the surgery[ 11 ]. The baseline characteristics and preoperative pulmonary function test results were comparable between the two patient groups.All patients underwent fiberoptic bronchoscopy-guided adjustment of the double-lumen endotracheal tube following intubation.During OLV, we maintain appropriate airway pressure and peripheral blood oxygen saturation. Consequently, the impact on oxygenation caused by imperfect alignment of the double-lumen tube is eliminated.Previous studies have revealed that high-­dose esketamine causes anaesthesia and is associated with side effects such as hallucinations and delirium[ 12 ].Our study employed an induction dose of 0.5 mg/kg and a maintenance dose of 0.15 mg/kg/h, which effectively maintained hemodynamic stability during surgery, provided analgesia, and reduced the incidence of adverse psychological reactions [ 13 ]. During OLV, the non-ventilated lung collapses completely but continues to receive a portion of cardiac output from the right ventricle, resulting in pulmonary shunting.The Increased of intrapulmonary shunting can lead to unilateral hypoxemia, hypoxic pulmonary vasoconstriction, and and lung recruitment after single lung during OLV,.which can cause the production and release of alveolar epithelial cytokines such as tumor necrosis factor and interleukin-6, increases capillary permeability, and severely causes alveolar edema, thereby exacerbating lung injury[ 14 ].Animal studies indicate[ 15 ] that continuous infusion of ketamine during one-lung ventilation reduces intrapulmonary shunt fraction.Our study found that the Qs/Qt was significantly reduced in Group E during surgery.Esketamine may reduce intrapulmonary shunting and improve intraoperative oxygenation in patients undergoing one-lung ventilation by relaxing airway smooth muscle and relieving bronchial and small airway spasm [ 16 ].Furthermore, studies by Eber et al. [ 17 ] indicate that the intraoperative use of esketamine reduces propofol consumption, consistent with the findings of this study.Propofol exhibits a dose-dependent inhibitory effect on HPV, and reducing its dosage may also help decrease Qs/Qt and improve oxygenation [ 7 ]. Lung compliance refers to the response of lung volume to unit changes in pressure, serving as a sensitive indicator of lung injury and ventilation. Higher lung compliance may reflect lower respiratory tract reactivity to some extent. Improving lung compliance, reducing respiratory work, and promoting gas exchange are crucial in patients undergoing general anesthesia[ 18 ].A previous study demonstrated that ketamine administered to ICU patients for pain relief increases lung compliance and reduces airway resistance [ 19 ].Children with refractory bronchospasm undergoing mechanical ventilation demonstrated favorable responses following continuous infusion of ketamine, with significant improvements in lung compliance and oxygenation [ 20 ].In our study,We found that compared with Group C, Group E exhibited a significant increase in Cdyn and a decrease in Pplat and Ppeak during 1 hour of one-lung ventilation.This may be because esketamine is a potential bronchodilator[ 21 ], which may help promote the clearance of respiratory secretions and mucus[ 22 ]. Adequate hemodynamics can maintain an appropriate ventilation-perfusion ratio, thereby enhancing oxygenation.In this study, compared with group C, group E exhibited hemodynamic stability, elevated mean arterial pressure, and reduced vasoactive drug usage.Esketamine reduces cardiac parasympathetic activity by blocking parasympathetic Na⁺ channels in the brainstem and inhibiting catecholamine reuptake, thereby elevating heart rate and blood pressure [ 23 ], which helps maintain hemodynamic stability in patients.Additionally, esketamine possesses sedative and analgesic effects, and its supplemental administration undoubtedly deepens anesthesia. However, the BIS values in group E patients consistently exceeded those in group C throughout the study, potentially related to esketamine's inhibition of NMDA receptors and hyperpolarization-activated cyclic nucleotide-gated (HCN) channels [ 24 ]. Effective postoperative pain management is crucial in the ERAS protocol, as pain can reduce tidal volume and impair the ability to effectively clear secretions and sputum through coughing.Esketamine is an NMDA receptor antagonist with agonist effects on delta and mu opioid receptors. It provides analgesia and prevents hyperalgesia[ 25 ].The reduced incidence of group E atelectasis observed in our study can be attributed to decreased coughing and purulent sputum production. Our study has certain limitations. First, inhalation anesthetics are currently believed to influence intrapulmonary shunting during OLV. To minimize the effects of inhalation anesthetics, we maintained anesthesia with the lowest possible concentration of sevoflurane in both groups. Nevertheless, we cannot rule out its potential impact on intrapulmonary shunting.Second, this study was a single-center randomized controlled trial with a small sample size. Some indicators showed only trends and did not yield statistically significant results. Future research should involve multicenter studies with larger sample sizes.Finally, both groups received a fixed dose of opioids to rule out differences in respiratory depression caused by varying opioid doses. Further evaluation is warranted regarding the efficacy of esketamine in patient-controlled analgesia (PCA). Esketamine's opioid-sparing effect [ 26 ] may offer additional benefits for respiratory function and postoperative outcomes following lung surgery. Conclusion In summary, Continuous infusion of esketamine during anesthesia in thoracoscopic surgery patients improves oxygenation (PaO 2 /FiO 2 ) during OLV and reduces the Qs/Qt. It also decreases Ppeak and Pplat while increasing Cdyn. This approach reduces postoperative complication rates and shortens hospital stays, offering a novel pathway for perioperative lung protection and promoting patient recovery. Declarations The manuscript reporting adheres to CONSORT guidelines. Ethics approval and consent to participate This study was conducted in accordance with the Declaration of Helsinki and Good Clinical Practice guidelines. Ethical approval was obtained from the Research Ethics Committee of The First Affiliated Hospital of Henan University(reference number: 2024-03-070) on August 28, 2024. The trial was registered online on December 09 2024 in the Chinese Clinical Trial Registry(ChiCTR2400093592, https://www.chictr.org.cn ), and the first patient was enrolled on December 15, 2024. Written informed consent was obtained from all participants in this study. Consent for publication Not applicable. Funding Henan Provincial Natural Science Foundation of China(NO.252300420120);Henan Provincial Science and Technology Program Projects(NO.242102310389) Author Contribution FCY contributed to writing the original draft, reviewing and editing,conceptualization, visualization, methodology, project administration, formal analysis, and investigation. HXD and SKM participated in investigation,writing review and editing, data curation, and resources. LJ wasresponsible for data curation, formal analysis, investigation, visualization,and software. ZXZ handled conceptualization, writing review and editing,visualization, methodology, supervision, validation, resources, project administration, and formal analysis. Acknowledgement We would like to acknowledge the hard and dedicated work of all the staff that implemented the intervention and evaluation components of the study. Data Availability All data generated or analysed during this study are included in this article.Further enquiries can be directed to the corresponding author. References Huang SQ, Zhang J, Zhang XX, Liu L, Yu Y, Kang XH, Wu XM, Zhu SM. Can Dexmedetomidine Improve Arterial Oxygenation and Intrapulmonary Shunt during One-lung Ventilation in Adults Undergoing Thoracic Surgery? A Meta-analysis of Randomized, Placebo-controlled Trials. Chin Med J. 2017;130(14):1707–14. https://doi.org/10.4103/0366-6999.209891 . Blank RS, Colquhoun DA, Durieux ME, Kozower BD, McMurry TL, Bender SP, Naik BI. Management of One-lung Ventilation: Impact of Tidal Volume on Complications after Thoracic Surgery. Anesthesiology. 2016;124(6):1286–95. https://doi.org/10.1097/ALN.0000000000001100 . Choi YS, Shim JK, Na S, Hong SB, Hong YW, Oh YJ. Pressure-controlled versus volume-controlled ventilation during one-lung ventilation in the prone position for robot-assisted esophagectomy. Surg Endosc. 2009;23(10):2286–91. https://doi.org/10.1007/s00464-008-0310-5 . Xia R, Yin H, Xia ZY, Mao QJ, Chen GD, Xu W. Effect of intravenous infusion of dexmedetomidine combined with inhalation of isoflurane on arterial oxygenation and intrapulmonary shunt during single-lung ventilation. Cell Biochem Biophys. 2013;67(3):1547–50. https://doi.org/10.1007/s12013-013-9659-8 . Lee 5, Kim SH, Lee N, Ban CY, M. G., Oh YJ. Effects of dexmedetomidine on oxygenation and lung mechanics in patients with moderate chronic obstructive pulmonary disease undergoing lung cancer surgery: A randomised double-blinded trial. Eur J Anaesthesiol. 2016;33(4):275–82. https://doi.org/10.1097/EJA.0000000000000405 . Qiao D, Liu W, Xue H, Liu R, Gao Y, Dong J, Wu W, Feng J, Li M, Yao L. Comparison of the effects of esketamine/midazolam and remifentanil/midazolam on respiratory mechanics in mechanically ventilated patients with acute respiratory distress syndrome. BMC Anesthesiol. 2025;25(1):339. https://doi.org/10.1186/s12871-025-03211-x . Lumb AB, Slinger P. Hypoxic pulmonary vasoconstriction: physiology and anesthetic implications. Anesthesiology. 2015;122(4):932–46. https://doi.org/10.1097/ALN.0000000000000569 . Zhang S, Zhou Y, Zhao L, Tian X, Jia M, Gu X, Feng N, An R, Yang L, Zheng G, Li J, Guo H, Fan R, Pei J. κ-opioid receptor activation protects against myocardial ischemia-reperfusion injury via AMPK/Akt/eNOS signaling activation. Eur J Pharmacol. 2018;833:100–8. https://doi.org/10.1016/j.ejphar.2018.05.043 . Perbet S, Verdonk F, Godet T, Jabaudon M, Chartier C, Cayot S, Guerin R, Morand D, Bazin JE, Futier E, Pereira B, Constantin JM. Low doses of ketamine reduce delirium but not opiate consumption in mechanically ventilated and sedated ICU patients: A randomised double-blind control trial. Anaesth Crit care pain Med. 2018;37(6):589–95. https://doi.org/10.1016/j.accpm.2018.09.006 . Tu W, Yuan H, Zhang S, Lu F, Yin L, Chen C, Li J. Influence of anesthetic induction of propofol combined with esketamine on perioperative stress and inflammatory responses and postoperative cognition of elderly surgical patients. Am J translational Res. 2021;13(3):1701–9. Williamson D, Turkoz I, Wajs E, Singh JB, Borentain S, Drevets WC. Adverse Events and Measurement of Dissociation After the First Dose of Esketamine in Patients With TRD. Int J Neuropsychopharmacol. 2023;26(3):198–206. https://doi.org/10.1093/ijnp/pyac081 . Zhang J, Ma Q, Li W, Li X, Chen X. S-Ketamine attenuates inflammatory effect and modulates the immune response in patients undergoing modified radical mastectomy: A prospective randomized controlled trial. Front Pharmacol. 2023;14:1128924. https://doi.org/10.3389/fphar.2023.1128924 . Guo W, Jin XJ, Yu J, Liu Y, Zhang JP, Yang DW, Zhang L, Guo JR. Effects of stellate ganglion block on the peri-operative vasomotor cytokine content and intrapulmonary shunt in patients with esophagus cancer. Asian Pac J cancer prevention: APJCP. 2014;15(21):9505–9. https://doi.org/10.7314/apjcp.2014.15.21.9505 . Lumb PD, Silvay G, Weinreich AI, Shiang H. A comparison of the effects of continuous ketamine infusion and halothane on oxygenation during one-lung anaesthesia in dogs. Can Anaesth Soc J. 1979;26(5):394–401. https://doi.org/10.1007/BF03006454 . Zou H, Wang LX, Wang M, Cheng C, Li S, Shen Q, Fang L, Liu R. (2019). MTOR-Mediated Autophagy Is Involved in the Protective Effect of Ketamine on Allergic Airway Inflammation. Journal of immunology research, 2019, 5879714. https://doi.org/10.1155/2019/5879714 Eberl S, Koers L, van Hooft J, de Jong E, Hermanides J, Hollmann MW, Preckel B. The effectiveness of a low-dose esketamine versus an alfentanil adjunct to propofol sedation during endoscopic retrograde cholangiopancreatography: A randomised controlled multicentre trial. Eur J Anaesthesiol. 2020;37(5):394–401. https://doi.org/10.1097/EJA.0000000000001134 . Wang X, Gong C, Zhang Y, Li S, Huang L, Chen L. Effects of dexmedetomidine on dynamic lung compliance in general anesthesia with desflurane: A randomized controlled study. Heliyon. 2023;9(6):e16672. https://doi.org/10.1016/j.heliyon.2023.e16672 . Wang X, Gong C, Zhang Y, Li S, Huang L, Chen L. Effects of dexmedetomidine on dynamic lung compliance in general anesthesia with desflurane: A randomized controlled study. Heliyon. 2023;9(6):e16672. https://doi.org/10.1016/j.heliyon.2023.e16672 . Youssef-Ahmed MZ, Silver P, Nimkoff L, Sagy M. Continuous infusion of ketamine in mechanically ventilated children with refractory bronchospasm. Intensive Care Med. 1996;22(9):972–6. https://doi.org/10.1007/BF02044126 . Williamson D, Turkoz I, Wajs E, Singh JB, Borentain S, Drevets WC. Adverse Events and Measurement of Dissociation After the First Dose of Esketamine in Patients With TRD. Int J Neuropsychopharmacol. 2023;26(3):198–206. https://doi.org/10.1093/ijnp/pyac081 . Odor PM, Bampoe S, Gilhooly D, Creagh-Brown B, Moonesinghe SR. (2020). Perioperative interventions for prevention of postoperative pulmonary complications: systematic review and meta-analysis. BMJ (Clinical research ed.), 368, m540. https://doi.org/10.1136/bmj.m540 Eberl S, Koers L, van Hooft JE, de Jong E, Schneider T, Hollmann MW, Preckel B. Sedation with propofol during ERCP: is the combination with esketamine more effective and safer than with alfentanil? Study protocol for a randomized controlled trial. Trials. 2017;18(1):472. https://doi.org/10.1186/s13063-017-2197-8 . Zanos P, Moaddel R, Morris PJ, Riggs LM, Highland JN, Georgiou P, Pereira EFR, Albuquerque EX, Thomas CJ, Zarate CA Jr, Gould TD. Ketamine and Ketamine Metabolite Pharmacology: Insights into Therapeutic Mechanisms. Pharmacol Rev. 2018;70(3):621–60. https://doi.org/10.1124/pr.117.015198 . Stéphan F, Boucheseiche S, Hollande J, Flahault A, Cheffi A, Bazelly B, Bonnet F. Pulmonary complications following lung resection: a comprehensive analysis of incidence and possible risk factors. Chest. 2000;118(5):1263–70. https://doi.org/10.1378/chest.118.5.1263 . Qiu D, Wang XM, Yang JJ, Chen S, Yue CB, Hashimoto K, Yang JJ. Effect of Intraoperative Esketamine Infusion on Postoperative Sleep Disturbance After Gynecological Laparoscopy: A Randomized Clinical Trial. JAMA Netw open. 2022;5(12):e2244514. https://doi.org/10.1001/jamanetworkopen.2022.44514 . Additional Declarations No competing interests reported. Cite Share Download PDF Status: Under Review Version 1 posted Reviewers agreed at journal 05 May, 2026 Reviews received at journal 17 Nov, 2025 Reviewers agreed at journal 14 Nov, 2025 Reviewers agreed at journal 12 Nov, 2025 Reviewers invited by journal 05 Nov, 2025 Editor assigned by journal 29 Oct, 2025 Editor invited by journal 06 Oct, 2025 Submission checks completed at journal 03 Oct, 2025 First submitted to journal 03 Oct, 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. 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-7593019","acceptedTermsAndConditions":true,"allowDirectSubmit":false,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":543863102,"identity":"57862ba3-4c5c-45c5-997f-78519c00049f","order_by":0,"name":"Fu Chunyan","email":"","orcid":"","institution":"The First Affiliated Hospital of Henan University","correspondingAuthor":false,"prefix":"","firstName":"Fu","middleName":"","lastName":"Chunyan","suffix":""},{"id":543863103,"identity":"0d3eedf1-7f4b-4a57-950d-c6eae721cebe","order_by":1,"name":"Han Xiaodi","email":"","orcid":"","institution":"The First Affiliated Hospital of Henan University","correspondingAuthor":false,"prefix":"","firstName":"Han","middleName":"","lastName":"Xiaodi","suffix":""},{"id":543863104,"identity":"e3286a8a-3189-4c2c-b7c0-bda527bac9c4","order_by":2,"name":"Shen Kemeng","email":"","orcid":"","institution":"The First Affiliated Hospital of Henan University","correspondingAuthor":false,"prefix":"","firstName":"Shen","middleName":"","lastName":"Kemeng","suffix":""},{"id":543863105,"identity":"05861737-c84f-4107-aa85-b20fb1dcbf63","order_by":3,"name":"Jing Liu","email":"","orcid":"","institution":"The First Affiliated Hospital of Henan University","correspondingAuthor":false,"prefix":"","firstName":"Jing","middleName":"","lastName":"Liu","suffix":""},{"id":543863106,"identity":"ab77c7f1-35b0-4b56-afdf-2dae0c07d0ee","order_by":4,"name":"Zheng Xiaozhen","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAAAyUlEQVRIiWNgGAWjYBACNobDBw4kVNjI8bM3EKmFj/FY4oMHZ9KMJXsOEKlFjvmMseHDtsOJG24kEOswtjNmEglshxMbbj7eeIOhxiaasBaeY2USCTzpxo2z04otGI6l5TYQ1CJxeJtEgoS1bLN0jpkEY8NhIrTIPwA6zICZsU3yDLFaGI4YGyQkOCv2SPAQrQUYyAkH0owleIB+SSDGL/INhw8c/PnPRs7++OGNNz7U2BDWggwMJBJIUQ7RQqqOUTAKRsEoGBkAAP6RQqjwXUAqAAAAAElFTkSuQmCC","orcid":"","institution":"The First Affiliated Hospital of Henan University","correspondingAuthor":true,"prefix":"","firstName":"Zheng","middleName":"","lastName":"Xiaozhen","suffix":""}],"badges":[],"createdAt":"2025-09-11 14:38:33","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-7593019/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-7593019/v1","draftVersion":[],"editorialEvents":[],"editorialNote":"","failedWorkflow":false,"files":[{"id":96049526,"identity":"10d194c5-f755-4426-8a93-84de94fce4a3","added_by":"auto","created_at":"2025-11-17 06:33:15","extension":"docx","order_by":1,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":309293,"visible":true,"origin":"","legend":"","description":"","filename":"EffectofintravenousesketamineonoxygenationandintrapulmonaryshuntingduringOnelungventilationinthoracoscopicsurgeryARandomizedControlledTrial.docx","url":"https://assets-eu.researchsquare.com/files/rs-7593019/v1/845b9d8c519140f7f8f08add.docx"},{"id":96049524,"identity":"a838e35d-ed45-4c9c-81fa-f9cb2992784a","added_by":"auto","created_at":"2025-11-17 06:33:15","extension":"json","order_by":8,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":7411,"visible":true,"origin":"","legend":"","description":"","filename":"9731c2d9df9d41108931789921a1b7ee.json","url":"https://assets-eu.researchsquare.com/files/rs-7593019/v1/d84a294abd89492411b3dcbd.json"},{"id":96247622,"identity":"fab858dd-5ccd-4f41-807f-eed58f34ef20","added_by":"auto","created_at":"2025-11-19 07:27:37","extension":"xml","order_by":9,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":113980,"visible":true,"origin":"","legend":"","description":"","filename":"9731c2d9df9d41108931789921a1b7ee1enriched.xml","url":"https://assets-eu.researchsquare.com/files/rs-7593019/v1/bcc39768a87b807c010d507e.xml"},{"id":96049534,"identity":"731c5935-8232-46d8-93a0-2e722388313b","added_by":"auto","created_at":"2025-11-17 06:33:15","extension":"pdf","order_by":10,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":198234,"visible":true,"origin":"","legend":"","description":"","filename":"Figure1CONSORTflowdiagramwithstudyoverviewandrecruitmentprofile..pdf","url":"https://assets-eu.researchsquare.com/files/rs-7593019/v1/8f61b775694a435528b05d3d.pdf"},{"id":96049532,"identity":"0bb72355-bed4-4604-aa60-cff79dfa6927","added_by":"auto","created_at":"2025-11-17 06:33:15","extension":"pdf","order_by":11,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":5851,"visible":true,"origin":"","legend":"","description":"","filename":"Figure2.pdf","url":"https://assets-eu.researchsquare.com/files/rs-7593019/v1/6689e9bf530fb64316df0a81.pdf"},{"id":96049527,"identity":"98f69a41-0bec-4d10-991e-0087a19a6458","added_by":"auto","created_at":"2025-11-17 06:33:15","extension":"pdf","order_by":12,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":6834,"visible":true,"origin":"","legend":"","description":"","filename":"Figure3.pdf","url":"https://assets-eu.researchsquare.com/files/rs-7593019/v1/59794cf3800d3d2573adcec9.pdf"},{"id":96049536,"identity":"c50b88cd-8522-4a70-95c0-e4592f8408dd","added_by":"auto","created_at":"2025-11-17 06:33:15","extension":"png","order_by":13,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":134745,"visible":true,"origin":"","legend":"","description":"","filename":"floatimage1.png","url":"https://assets-eu.researchsquare.com/files/rs-7593019/v1/7d9cd801dba3de0a12182726.png"},{"id":96049530,"identity":"606d5b89-df9f-40df-8566-1a24cc224643","added_by":"auto","created_at":"2025-11-17 06:33:15","extension":"jpeg","order_by":14,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":199412,"visible":true,"origin":"","legend":"","description":"","filename":"floatimage2.jpeg","url":"https://assets-eu.researchsquare.com/files/rs-7593019/v1/548dec8ed98c57cde542b616.jpeg"},{"id":96247698,"identity":"dcb726bf-c06a-4971-b20c-ceea05168198","added_by":"auto","created_at":"2025-11-19 07:27:41","extension":"jpeg","order_by":15,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":264758,"visible":true,"origin":"","legend":"","description":"","filename":"floatimage3.jpeg","url":"https://assets-eu.researchsquare.com/files/rs-7593019/v1/57f4405ee4d476de7490a82d.jpeg"},{"id":96049531,"identity":"66c000a7-b966-4477-9cdc-9c6ff8f93a2f","added_by":"auto","created_at":"2025-11-17 06:33:15","extension":"png","order_by":16,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":42631,"visible":true,"origin":"","legend":"","description":"","filename":"Onlinefloatimage1.png","url":"https://assets-eu.researchsquare.com/files/rs-7593019/v1/3c30ad878052858cc7d21b65.png"},{"id":96248200,"identity":"d2cd6e35-524c-44d8-a209-4c5dec37c9e9","added_by":"auto","created_at":"2025-11-19 07:28:09","extension":"png","order_by":17,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":42222,"visible":true,"origin":"","legend":"","description":"","filename":"Onlinefloatimage2.png","url":"https://assets-eu.researchsquare.com/files/rs-7593019/v1/a0ee57588ab75c84b95aa64f.png"},{"id":96049528,"identity":"cb76bb8d-6159-4aa8-b1f9-6f6ba3c0b762","added_by":"auto","created_at":"2025-11-17 06:33:15","extension":"png","order_by":18,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":51629,"visible":true,"origin":"","legend":"","description":"","filename":"Onlinefloatimage3.png","url":"https://assets-eu.researchsquare.com/files/rs-7593019/v1/03dedfc5ebe856f51999669f.png"},{"id":96247900,"identity":"4d4442e9-aa35-4bdb-85d5-91ccd2840ed2","added_by":"auto","created_at":"2025-11-19 07:27:49","extension":"xml","order_by":19,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":108768,"visible":true,"origin":"","legend":"","description":"","filename":"9731c2d9df9d41108931789921a1b7ee1structuring.xml","url":"https://assets-eu.researchsquare.com/files/rs-7593019/v1/d235f513ce5129802c222c17.xml"},{"id":96049537,"identity":"697500b9-4b0d-45bd-8f9c-4709dde9fe3c","added_by":"auto","created_at":"2025-11-17 06:33:15","extension":"html","order_by":20,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":121053,"visible":true,"origin":"","legend":"","description":"","filename":"earlyproof.html","url":"https://assets-eu.researchsquare.com/files/rs-7593019/v1/d8b48c84ae461323b3a74f51.html"},{"id":96049521,"identity":"030765ef-b1dd-41b6-a945-118e4b737a3e","added_by":"auto","created_at":"2025-11-17 06:33:15","extension":"png","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":282288,"visible":true,"origin":"","legend":"\u003cp\u003eCONSORT flow diagram with study overview and recruitment profile.\u003c/p\u003e","description":"","filename":"Figure1CONSORTflowdiagramwithstudyoverviewandrecruitmentprofile.1.png","url":"https://assets-eu.researchsquare.com/files/rs-7593019/v1/7973634f5cb04d8d6819db03.png"},{"id":96049520,"identity":"75ae456d-4253-4902-85f6-3f14d914b7c8","added_by":"auto","created_at":"2025-11-17 06:33:15","extension":"png","order_by":2,"title":"Figure 2","display":"","copyAsset":false,"role":"figure","size":17991,"visible":true,"origin":"","legend":"\u003cp\u003e(A) ,PaO2/FiO2. (B), Intrapulmonary shunt. .\u003cstrong\u003e \u003c/strong\u003eQs/ Qt: intrapulmonary shunt ratio;Data are presented as the mean± SD. * P \u0026lt; 0.05 vs T0; \u003csup\u003e#\u003c/sup\u003e P \u0026lt; 0.05 vs group\u003c/p\u003e","description":"","filename":"Figure1CONSORTflowdiagramwithstudyoverviewandrecruitmentprofile.2.png","url":"https://assets-eu.researchsquare.com/files/rs-7593019/v1/28b3e879b295a8109c6400f1.png"},{"id":96049522,"identity":"8d941122-a957-4ec1-9f84-8b48797174b1","added_by":"auto","created_at":"2025-11-17 06:33:15","extension":"png","order_by":3,"title":"Figure 3","display":"","copyAsset":false,"role":"figure","size":25463,"visible":true,"origin":"","legend":"\u003cp\u003eComparison of hemodynamics and BIS.(A), Mean Arterial Pressure (B), Heart Rate (C),Bispectral Index.\u003c/p\u003e\n\u003cp\u003eMAP, mean arterial pressure;HR, heart rate;BIS:Bispectral Index.Data are presented as the mean± SD.* P \u0026lt; 0.05 vs T0; \u003csup\u003e#\u003c/sup\u003e P \u0026lt; 0.05 vs group\u003c/p\u003e","description":"","filename":"Figure1CONSORTflowdiagramwithstudyoverviewandrecruitmentprofile.3.png","url":"https://assets-eu.researchsquare.com/files/rs-7593019/v1/8d5aacd384f0509c6d905a9d.png"},{"id":96362769,"identity":"12af7b24-4e87-4448-b220-77d991837b12","added_by":"auto","created_at":"2025-11-20 09:48:57","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":977561,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-7593019/v1/0920479a-06c2-448c-bb8c-78f8910dbfa9.pdf"}],"financialInterests":"No competing interests reported.","formattedTitle":"Effect of intravenous esketamine on oxygenation and intrapulmonary shunting during One-lung ventilation in thoracoscopic surgery: A Randomized Controlled Trial","fulltext":[{"header":"Introduction","content":"\u003cp\u003eOne-lung ventilation (OLV) is extensively utilized in video-assisted thoracoscopic surgery (VATS), owing to its capacity to expand the surgical visual field, achieve effective isolation of the lungs, and minimize cross-infection between the two lungs[\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e, \u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e].However, during one-lung ventilation (OLV), the body relies on one lung for oxygenation, resulting in ventilation/perfusion (V/Q) imbalance, which increases intrapulmonary shunting and thereby increases the risk of hypoxemia in patients[4,5].Hypoxic pulmonary vasoconstriction (HPV) is an intrinsic homeostatic mechanism of the pulmonary vascular system that optimizes ventilation-perfusion matching by redirecting pulmonary blood flow to highly oxygenated lung segments [\u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e]. It is an important protective mechanism for maintaining arterial oxygenation during OLV.In the anesthesia management of OLV patients, it is important to administer drugs that have no inhibitory effect or minimal inhibitory effect on this mechanism.\u003c/p\u003e\u003cp\u003eEsketamine is an N-methyl-D-aspartate (NMDA) receptor antagonist with sedative and analgesic effects.It has been reported that esketamine can block L-type calcium channels, relax bronchial smooth muscle, increase lung compliance, and increase minute ventilation [\u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e11\u003c/span\u003e, \u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e12\u003c/span\u003e].Intravenous infusion of esketamine can improve static lung compliance (Cst) and PaO₂/FiO₂ ratio in mechanically ventilated ARDS patients[\u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e7\u003c/span\u003e].In addition, as an analgesic, esketamine can also reduce opioid consumption and significantly relieve postoperative pain [\u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e6\u003c/span\u003e].However, the effects of intravenous esketamine on intraoperative oxygenation and intrapulmonary shunting in patients undergoing one-lung ventilation remain unknown.\u003c/p\u003e\u003cp\u003eTherefore, this study aims to investigate the effects of intraoperative intravenous administration of esketamine on intraoperative oxygenation and intrapulmonary shunting in patients undergoing one-lung ventilation. We hypothesize that intravenous administration of esketamine may reduce intraoperative arterial oxygenation (PaO₂/FiO₂) and decrease pulmonary shunting in patients undergoing one-lung ventilation.\u003c/p\u003e"},{"header":"Materials and methods","content":"\u003cdiv id=\"Sec3\" class=\"Section2\"\u003e\u003ch2\u003eStudy Design and Ethics\u003c/h2\u003e\u003cp\u003e This study was designed as a prospective, randomized,parallel-controlled trial.The protocol was approved by the Ethics Committee of the First Affiliated Hospital of Henan University (2024-03-070) and was registered at the Chinese Clinical Trial Registry(ChiCTR2400093592).This report adheres to the CONSORT guidelines. The study was conducted according to the guidelines of the Declaration of Helsinki with Good Clinical Practice. All participants provided written informed consent before enrolment.\u003c/p\u003e\u003c/div\u003e\n\u003ch3\u003eStudy Population\u003c/h3\u003e\n\u003cp\u003eFifty patients who underwent elective thoracoscopic lobectomy.All patients were ASA I-II, aged 18-65years, and their body mass index was 18\u0026ndash;30 kg/m\u003csup\u003e2\u003c/sup\u003e. According to the eighth edition of staging standard of International Association for Lung Cancer Research (IASLC), all the selected lung cancer patients were in stage IA.\u003c/p\u003e\u003cp\u003eExclusion criteria were as follows:(1)Patients diagnosed with severe hypertension or cardiac conduction block (second- or third-degree atrioventricular block, bundle branch block);(2) The patient has a history of thoracic surgery.(3) Patients with liver parenchymal damage (ALT or AST\u0026thinsp;\u0026gt;\u0026thinsp;2\u0026times;normal value), Child-Pugh C-class cirrhosis, or renal failure (SCr\u0026thinsp;\u0026gt;\u0026thinsp;177 \u0026micro;mol /l);(4) Patients addicted to opiate drugs or sedative-hypnotic drugs;(5) Patients who are allergic to esketamine and other commonly used anesthetics;(6) Patients with mental disorders and those who are unable to cooperate.\u003c/p\u003e\u003cp\u003ePatients who require conversion to open-chest surgery during the procedure, single-lung ventilation for \u0026gt;\u0026thinsp;4 hours, or transfer to the intensive care unit (ICU) for further treatment after surgery will be withdrawn from the study.\u003c/p\u003e\n\u003ch3\u003ePatient grouping and randomization\u003c/h3\u003e\n\u003cp\u003eUsing SPSS 25.0 (IBM Corp., Armonk, NY, USA) and computer-generated sequences, patients were randomly assigned in a 1:1 ratio to the esketamine group (E group) or the control group (C group).Randomized grouping envelopes contain grouping information, and nurses prepare study medications according to group assignments.Dilute the esketamine group with 50 mL of saline to a concentration of 1 mg/mL.The control group was prepared with an equal volume of saline solution.Both groups received the prepared medication using syringes that looked the same.Patients, clinicians, and outcome assessors remained blinded throughout the study period.\u003c/p\u003e\n\u003ch3\u003eIntervention\u003c/h3\u003e\n\u003cp\u003ePatients in group esketamine received a bolus of esketamine 0.5mg/kg before the induction of anesthesia, then followed by a continuous infusion of 0.15 mg/kg/h intraoperatively until the end of surgery. Patients in group control received 0.9% saline in place of lidocaine at the same time points.\u003c/p\u003e\u003cp\u003e\u003cb\u003eAnesthesia Protocol\u003c/b\u003e\u003c/p\u003e\u003cp\u003eAll patients underwent standard preoperative preparation, which included a fasting period of 8 h and fluid restriction for 2 h prior to the procedure. No preoperative medications were administered.Upon admission to the room, the patient's ECG, NBP, SpO₂, and BIS (Aspect Medical Systems, Newton, MA, USA) are monitored.Under local anesthesia, radial artery puncture and catheterization were performed for invasive blood pressure monitoring and arterial blood gas analysis (GEM Premier 4000, Instrumentation Laboratory, Lexington, MA, USA).\u003c/p\u003e\u003cp\u003eAnesthesia was induced with esketamine 0.5mg/kg (or the same volume of 0.9% saline),propofol 0.5-1 mg/kg,sufentanil 0.4 \u0026micro;g/kg,rocuronium 0.6 mg/kg.The esketamine or 0.9% saline infusion was initiated after induction and dosed as described above.Anesthesia was maintained by remifentanil 0.1\u0026ndash;0.2\u0026micro;g /kg/ min and propofol, combined with sevoflurane 1%.Maintain the BIS values between 40 and 60 by adjusting the dose of propofol.All patients underwent tracheal intubation using a double-lumen catheter (Broncho-Cath, Mallinckrodt, Dublin, Ireland) following induction of anesthesia.The position of the catheter was adjusted under a fiber-optic bronchoscope and connected to the anesthesia machine (Primus iventilator, Drager TM Medical,Lubeck,Germany)for volume-controlled mechanical ventilation.Mechanical ventilation parameters are set as follows[\u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e8\u003c/span\u003e]:during double-lung ventilation, tidal volume (VT) 6\u0026ndash;8 mL/kg, during one-lung ventilation, VT 5\u0026ndash;6 mL/kg, frequency (f) 12\u0026ndash;15 times/min, PEEP 5cmH2O, I : E\u0026thinsp;=\u0026thinsp;1 : 2, FIO2\u0026thinsp;=\u0026thinsp;1:0, and PETCO2 maintained in the range of 35-45mmHg.Mean arterial pressure was maintained within \u0026plusmn;\u0026thinsp;20% of the baseline.Hypotension was treated with norepinephrine 4\u0026micro;g or ephedrine 5mg; episodes of hypertension were managed by increasing the propofol or remifentanil infusion rate.If hypertension persisted despite sufficient analgesia and depth of anesthesia, intravenous bolus of urapidil was given.At the conclusion of surgery, discontinue all medications, neuromuscular block was reversed and extubation was attempted in the operating theatre .Patients who did not meet extubation criteria were transferred to the post-anesthesia care unit (PACU).\u003c/p\u003e\u003cp\u003ePostoperative patient-controlled intravenous analgesia (PCA) was performed with drug formulations (sufentanil 2\u0026micro;g/kg, Ondansetron 16 mg, 0.9% saline diluted to 100 mL) using a set lock time of 15 min, a background infusion dos-e to 2 mL/h, and the PCA was set at 0.5 mL/times to maintain the visual analogue scale (VAS) below or equal to 3 points.Discharge to the surgical wards when Aldrete scores of greater than or equal to 8 out of 10 were achieved.\u003c/p\u003e\n\u003ch3\u003eObservational indexes\u003c/h3\u003e\n\u003cp\u003eThe primary outcome was lung oxygenation(PaO2/FIO2 ) and the pulmonary shunt fraction (Qs/Qt).The secondary outcomes included: (1) parameters reflecting mechanics༚ Peak airway pressure(Ppeak)、Airway Platform Pressure༈Pplat༉、dynamic lung compliance(Cdyn\u0026thinsp;=\u0026thinsp;Vt/(Pmax-PEEP)); (2) hemodynamics (heart rate and mean arterial pressure);༈3༉Incidence of Postoperative Pulmonary Complications (PPCs).PPCs is defined as the presence of at least one of the following: decreased saturation (defined as SpO\u003csub\u003e2\u003c/sub\u003e\u0026thinsp;\u0026lt;\u0026thinsp;90% in room air), clinical signs and symptoms (including respiratory infection, respiratory failure, and bronchospasm), and abnormal chest X-ray findings (including pleural effusion, atelectasis, pneumothorax, aspiration pneumonia, and pulmonary edema)[\u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e14\u003c/span\u003e].\u003c/p\u003e\u003cdiv id=\"Sec8\" class=\"Section2\"\u003e\u003ch2\u003eData Collection\u003c/h2\u003e\u003cp\u003eThe day before the operation, the patient\u0026rsquo;s baseline characteristics were recorded.The heart rate (HR) and mean arterial pressure(MAP) were were measured bfore anesthesia induction (T0),30 min after OLV(T1),60 min after OLV(T2) and 20 min after reinstitution of two-lung ventilation(T3),and collect 1 milliliter of blood from the radial artery for arterial blood gas analysis, calculating the lung oxygenation(PaO2/FIO2 ),the pulmonary shunt fraction (Qs/Qt).Pulmonary shunt fraction (Qs/Qt) was calculated using the following formula:\u003c/p\u003e\u003cp\u003eQs/Qt= (CcO2\u0026thinsp;\u0026minus;\u0026thinsp;CaO2)/(CcO2\u0026thinsp;\u0026minus;\u0026thinsp;CvO2).\u003c/p\u003e\u003cp\u003eWhereby CaO2(oxygen content of arterial blood) = (PaO2\u0026times;0.0031) + (Hb \u0026times; 1.34 \u0026times; SaO2).\u003c/p\u003e\u003cp\u003eCvO2(oxygen content of venous blood) = (PvO2\u0026times; 0.0031) +(Hb \u0026times; 1.34 \u0026times; SvO2).\u003c/p\u003e\u003cp\u003eCcO2= ([FiO2\u0026times; (PB\u0026thinsp;\u0026minus;\u0026thinsp;pH2O) \u0026minus; (PaCO2/RQ)] \u0026times;0.0031) + (Hb \u0026times; 1.34).\u003c/p\u003e\u003cp\u003ePB \u0026ndash;Barometric pressure (760 mmHg), pH2O\u0026ndash;47 mmHg,\u003c/p\u003e\u003cp\u003eHb \u0026ndash;Hemoglobin, RQ \u0026ndash;Respiratory quotient (0.8).\u003c/p\u003e\u003c/div\u003e\n\u003ch3\u003eStatistics\u003c/h3\u003e\n\u003cp\u003eSample size calculations were performed using PASS software (Version 11.0.7, NCS, LCC, Kaysville, UT, USA).The primary outcome was lung oxygenation expressed by PaO2/FIO2 ratio during OLV,preliminary study results indicated an oxygenation index of 192\u0026thinsp;\u0026plusmn;\u0026thinsp;67 mmHg at OLV 60 min,The difference in PaO₂/FiO₂ ratios between the two groups was 50 mmHg and was statistically significant,With a bilateral α of 0.05 and a power of 90%,the sample size was calculated as N1\u0026thinsp;=\u0026thinsp;N2\u0026thinsp;=\u0026thinsp;25 for each group. Our study finally included a total of 50 patients.\u003c/p\u003e\u003cp\u003eThe SPSS 23.0 software package (IBM Corporation,Armonk, NY, USA) was used for statistical analysis. Categorical data were expressed as frequencies or percentages and analyzed using the chi-square (χ2) test or Fisher\u0026rsquo;s exact test. The Kolmogorov-Smirnov test was used to assess the normality of continuous variables. Normally distributed continuous variables were presented as the mean\u0026thinsp;\u0026plusmn;\u0026thinsp;standard deviation (SD), and compared between groups using the independent samples t-test. For nonnormally distributed quantitative variables, data were expressed as median (interquartile range [IQR]), and comparisons were made using the Mann-Whitney U test.Analysis of variance (ANOVA) was used to compare different time points within groups. A p-value of less than 0.05 was considered statistically significant.\u003c/p\u003e"},{"header":"Results","content":"\u003cp\u003eSeventy patients were determined to be eligible for this study, but nine patients were excluded at initial screening . Of the 61 patients, 11 were excluded from the study because of incomplete data and/or changes of surgical plan. Data from 25 patients in each group were analysed (Fig. 1).There were no differences between groups regarding baseline characteristics(Table 1).\u003c/p\u003e\n\u003cp\u003eAt T0, there were no statistically significant differences between the two groups in PaO₂/FiO₂ and Qs/Qt (\u003cem\u003eP\u003c/em\u003e \u0026gt; 0.05) .Compared with T0, PaO\u003csub\u003e2\u003c/sub\u003e/FiO\u003csub\u003e2\u003c/sub\u003ewere lower in groups E and C at T1 to T3, while Qs/Qt significantly increased.(\u003cem\u003eP\u003c/em\u003e \u0026lt; 0.05)（Fig.2）.Compared with group C,PaO2/FiO2 were higher and Qs/Qt were lower in group E at the T1、T2 and T3 time points (P \u0026lt; 0.05) (Fig. 2).\u003c/p\u003e\n\u003cp\u003eCompared with group C,Ppeak and Pplat were lower and Cdyn were higher in group E at the T2 and T3 time points \u003cem\u003e(P\u003c/em\u003e \u0026lt; 0.05).The differences in PaCO\u003csub\u003e2\u003c/sub\u003e between the two groups at each time point were not statistically significant (\u003cem\u003eP\u003c/em\u003e \u0026gt; 0.05) (Table 2).\u003c/p\u003e\n\u003cp\u003eThere was no statistically significant difference in hemodynamic parameters (MAP, HR) between the two groups at T0-T4 (\u003cem\u003eP\u003c/em\u003e \u0026gt; 0.05)（Fig 3）.Compared with group C, fewer patients in group E required vasopressors during surgery (8% vs. 24%, P \u0026lt; 0.001）（Table 3）.\u003c/p\u003e\n\u003cp\u003eThe total intraoperative consumption of remifentanil and propofol, as well as the postoperative consumption of sufentanil in group E was less than that in group C (P \u0026lt; 0.05) (Table 3).\u003c/p\u003e\n\u003cp\u003eThe incidence of atelectasis in group E was 16% (4/25), significantly lower than the 32% (8/25) observed in group C (\u003cem\u003eP\u003c/em\u003e \u0026lt; 0.05).There was no statistically significant difference in the incidence of other PPCs and the time to chest drainage tube removal between the two groups (P \u0026gt; 0.05).The postoperative hospital stay in group E was shorter than that in group C (7.76 \u0026plusmn; 1.35 vs. 8.45 \u0026plusmn; 1.66, P = 0.045)（Table 4）.\u003c/p\u003e\n\u003cp\u003eTable 1 Demographic and Intraoperative Characteristics\u003c/p\u003e\n\u003ctable border=\"1\" cellspacing=\"0\" cellpadding=\"0\"\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 182px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 140px;\"\u003e\n \u003cp\u003eEsketamine\u003c/p\u003e\n \u003cp\u003e(n = 25)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 138px;\"\u003e\n \u003cp\u003eControl\u003c/p\u003e\n \u003cp\u003e(n = 25)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 119px;\"\u003e\n \u003cp\u003eP value\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 182px;\"\u003e\n \u003cp\u003eAge (years)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 140px;\"\u003e\n \u003cp\u003e56.15 \u0026plusmn; 9.57\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 138px;\"\u003e\n \u003cp\u003e56.58 \u0026plusmn; 9.53\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 119px;\"\u003e\n \u003cp\u003e0.832\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 182px;\"\u003e\n \u003cp\u003eSex (M/F)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 140px;\"\u003e\n \u003cp\u003e15/10\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 138px;\"\u003e\n \u003cp\u003e13/12\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 119px;\"\u003e\n \u003cp\u003e0.366\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 182px;\"\u003e\n \u003cp\u003eBMI (kgm\u003csup\u003e2\u003c/sup\u003e)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 140px;\"\u003e\n \u003cp\u003e24.6 \u0026plusmn; 4.0\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 138px;\"\u003e\n \u003cp\u003e22.3 \u0026plusmn; 5.7\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 119px;\"\u003e\n \u003cp\u003e0.276\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 182px;\"\u003e\n \u003cp\u003eASA rating(Ⅰ/II)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 140px;\"\u003e\n \u003cp\u003e3/22\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 138px;\"\u003e\n \u003cp\u003e4/21\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 119px;\"\u003e\n \u003cp\u003e0.702\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 182px;\"\u003e\n \u003cp\u003eHypertension\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 140px;\"\u003e\n \u003cp\u003e9（36%）\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 138px;\"\u003e\n \u003cp\u003e8（32%）\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 119px;\"\u003e\n \u003cp\u003e0.794\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 182px;\"\u003e\n \u003cp\u003eSmoking history (no/current)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 140px;\"\u003e\n \u003cp\u003e19/6\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 138px;\"\u003e\n \u003cp\u003e20/5\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 119px;\"\u003e\n \u003cp\u003e0.746\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd rowspan=\"4\" valign=\"top\" style=\"width: 182px;\"\u003e\n \u003cp\u003ePreoperative spirometry\u003c/p\u003e\n \u003cp\u003eFEV1, % predicted\u003c/p\u003e\n \u003cp\u003eFVC, % predicted\u003c/p\u003e\n \u003cp\u003eFEV1/FVC, %\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 140px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 138px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 119px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 140px;\"\u003e\n \u003cp\u003e82 \u0026plusmn; 18\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 138px;\"\u003e\n \u003cp\u003e81 \u0026plusmn; 17\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 119px;\"\u003e\n \u003cp\u003e0.734\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 140px;\"\u003e\n \u003cp\u003e85 \u0026plusmn; 16\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 138px;\"\u003e\n \u003cp\u003e86 \u0026plusmn; 14\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 119px;\"\u003e\n \u003cp\u003e0.930\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 140px;\"\u003e\n \u003cp\u003e82 \u0026plusmn; 13\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 138px;\"\u003e\n \u003cp\u003e80 \u0026plusmn; 12\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 119px;\"\u003e\n \u003cp\u003e0.973\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 182px;\"\u003e\n \u003cp\u003ePH\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 140px;\"\u003e\n \u003cp\u003e7.41 \u0026plusmn; 0.02\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 138px;\"\u003e\n \u003cp\u003e7.40 \u0026plusmn; 0.03\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 119px;\"\u003e\n \u003cp\u003e0.978\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 182px;\"\u003e\n \u003cp\u003eHb(mg l\u003csup\u003e\u0026minus;1\u003c/sup\u003e)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 140px;\"\u003e\n \u003cp\u003e118.3 \u0026plusmn; 12.5\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 138px;\"\u003e\n \u003cp\u003e118.8 \u0026plusmn; 11.9\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 119px;\"\u003e\n \u003cp\u003e0.934\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 182px;\"\u003e\n \u003cp\u003ePreoperative \u0026nbsp;LVEF (%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 140px;\"\u003e\n \u003cp\u003e64.72 \u0026plusmn; 4.11\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 138px;\"\u003e\n \u003cp\u003e65.45 \u0026plusmn; 4.74\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 119px;\"\u003e\n \u003cp\u003e0.374\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 182px;\"\u003e\n \u003cp\u003eOperation time (min)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 140px;\"\u003e\n \u003cp\u003e180.7 \u0026plusmn; 38.9\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 138px;\"\u003e\n \u003cp\u003e183.3 \u0026plusmn; 41.5\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 119px;\"\u003e\n \u003cp\u003e0.857\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 182px;\"\u003e\n \u003cp\u003eOLV time (min)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 140px;\"\u003e\n \u003cp\u003e114.4 \u0026plusmn; 32.3\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 138px;\"\u003e\n \u003cp\u003e118.1 \u0026plusmn; 34.4\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 119px;\"\u003e\n \u003cp\u003e0.842\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 182px;\"\u003e\n \u003cp\u003eFluid intake (ml)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 140px;\"\u003e\n \u003cp\u003e790.16\u0026plusmn;80.47\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 138px;\"\u003e\n \u003cp\u003e798.44\u0026plusmn;78.62\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 119px;\"\u003e\n \u003cp\u003e0.247\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 182px;\"\u003e\n \u003cp\u003eEstimated blood loss (ml)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 140px;\"\u003e\n \u003cp\u003e112.52\u0026plusmn;45.32\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 138px;\"\u003e\n \u003cp\u003e116.46\u0026plusmn;50.21\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 119px;\"\u003e\n \u003cp\u003e0.694\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 182px;\"\u003e\n \u003cp\u003eUrine volume (mL)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 140px;\"\u003e\n \u003cp\u003e263.74\u0026plusmn;105.63\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 138px;\"\u003e\n \u003cp\u003e270.83\u0026plusmn;110.44\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 119px;\"\u003e\n \u003cp\u003e0.396\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd rowspan=\"6\" valign=\"top\" style=\"width: 182px;\"\u003e\n \u003cp\u003eRight/left lobectomy\u003c/p\u003e\u003cbr\u003eRight upper lobe\u003cp\u003e\u003cbr\u003e\u003c/p\u003e\n \u003cp\u003eRight middle lobe\u003c/p\u003e\n \u003cp\u003e\u003cbr\u003e\u003c/p\u003e\n \u003cp\u003eRight lower lobe\u003c/p\u003e\u003cbr\u003e\n \u003cp\u003eLeft upper lobe\u003c/p\u003e\n \u003cp\u003e\u003cbr\u003e\u003c/p\u003e\n \u003cp\u003eLeft lower lobe\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 140px;\"\u003e\n \u003cp\u003e11/14\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 138px;\"\u003e\n \u003cp\u003e10/15\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 119px;\"\u003e\n \u003cp\u003e0.999\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 140px;\"\u003e\n \u003cp\u003e6（24%）\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 138px;\"\u003e\n \u003cp\u003e8（32%）\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 119px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 140px;\"\u003e\n \u003cp\u003e5（20%）\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 138px;\"\u003e\n \u003cp\u003e2（8%）\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 119px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 140px;\"\u003e\n \u003cp\u003e2（8%）\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 138px;\"\u003e\n \u003cp\u003e4（16%）\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 119px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 140px;\"\u003e\n \u003cp\u003e8（32%）\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 138px;\"\u003e\n \u003cp\u003e6（24%）\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 119px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 140px;\"\u003e\n \u003cp\u003e4（16%）\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 138px;\"\u003e\n \u003cp\u003e5（20%）\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 119px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n\u003c/table\u003e\n\u003cp\u003eData are presented as number of patients or mean \u0026plusmn; standard deviation, number or percentage of patients. ASA, American Society of Anesthesiologists; FEV1, forced expiratory volume in 1 s; FVC, forced vital capacity; OLV, one-lung ventilation; LVEF%, Left Ventricular Ejection Fractions.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eTable 2 Haemodynamic and respiratory changes\u003c/strong\u003e\u003c/p\u003e\n\u003ctable border=\"1\" cellspacing=\"0\" cellpadding=\"0\" align=\"\" width=\"560\"\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 122px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 179px;\"\u003e\n \u003cp\u003eEsketamine\u003c/p\u003e\n \u003cp\u003e(n = 25)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 145px;\"\u003e\n \u003cp\u003eControl\u003c/p\u003e\n \u003cp\u003e(n = 25)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 114px;\"\u003e\n \u003cp\u003eP value\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 122px;\"\u003e\n \u003cp\u003ePaCO2 (mmHg)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 179px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 145px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 114px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 122px;\"\u003e\n \u003cp\u003eT0\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 179px;\"\u003e\n \u003cp\u003e38..58 \u0026plusmn; 4.82\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 145px;\"\u003e\n \u003cp\u003e38.79 \u0026plusmn; 5.65\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 114px;\"\u003e\n \u003cp\u003e0.861\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 122px;\"\u003e\n \u003cp\u003eT1\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 179px;\"\u003e\n \u003cp\u003e40.10 \u0026plusmn; 5.35\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 145px;\"\u003e\n \u003cp\u003e40.95 \u0026plusmn; 5.51\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 114px;\"\u003e\n \u003cp\u003e0.485\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 122px;\"\u003e\n \u003cp\u003eT2\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 179px;\"\u003e\n \u003cp\u003e41.23 \u0026plusmn; 4.41\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 145px;\"\u003e\n \u003cp\u003e41.83 \u0026plusmn; 5.95\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 114px;\"\u003e\n \u003cp\u003e0.176\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 122px;\"\u003e\n \u003cp\u003eT3\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 179px;\"\u003e\n \u003cp\u003e42.91 \u0026plusmn; 4.42\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 145px;\"\u003e\n \u003cp\u003e42.43 \u0026plusmn; 5.12\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 114px;\"\u003e\n \u003cp\u003e0.643\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 122px;\"\u003e\n \u003cp\u003ePpeak (cmH2O)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 179px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 145px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 114px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 122px;\"\u003e\n \u003cp\u003eT1\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 179px;\"\u003e\n \u003cp\u003e19.24\u0026plusmn;2.42\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 145px;\"\u003e\n \u003cp\u003e20.56\u0026plusmn;3.50\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 114px;\"\u003e\n \u003cp\u003e0.143\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 122px;\"\u003e\n \u003cp\u003eT2\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 179px;\"\u003e\n \u003cp\u003e20.13\u0026plusmn;3.27\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 145px;\"\u003e\n \u003cp\u003e22.72\u0026plusmn;3.27\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 114px;\"\u003e\n \u003cp\u003e0.012\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 122px;\"\u003e\n \u003cp\u003eT3\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 179px;\"\u003e\n \u003cp\u003e17.44\u0026plusmn;2.51\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 145px;\"\u003e\n \u003cp\u003e20.12\u0026plusmn;2.77\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 114px;\"\u003e\n \u003cp\u003e\u0026lt;0.001\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 122px;\"\u003e\n \u003cp\u003ePplato (cmH2O)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 179px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 145px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 114px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 122px;\"\u003e\n \u003cp\u003eT1\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 179px;\"\u003e\n \u003cp\u003e19.24\u0026plusmn;2.42\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 145px;\"\u003e\n \u003cp\u003e21.56\u0026plusmn;3.50\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 114px;\"\u003e\n \u003cp\u003e0.135\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 122px;\"\u003e\n \u003cp\u003eT2\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 179px;\"\u003e\n \u003cp\u003e20.12\u0026plusmn;3.27\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 145px;\"\u003e\n \u003cp\u003e22.72\u0026plusmn;3.71\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 114px;\"\u003e\n \u003cp\u003e0.015\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 122px;\"\u003e\n \u003cp\u003eT3\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 179px;\"\u003e\n \u003cp\u003e17.44\u0026plusmn;2.51#\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 145px;\"\u003e\n \u003cp\u003e20.12\u0026plusmn;2.77#\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 114px;\"\u003e\n \u003cp\u003e\u0026lt;0.001\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 122px;\"\u003e\n \u003cp\u003eCdyn(mL/cmH2O)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 179px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 145px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 114px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 122px;\"\u003e\n \u003cp\u003eT1\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 179px;\"\u003e\n \u003cp\u003e31.65\u0026plusmn;10.19\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 145px;\"\u003e\n \u003cp\u003e30.42\u0026plusmn;8.82\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 114px;\"\u003e\n \u003cp\u003e0.650\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 122px;\"\u003e\n \u003cp\u003eT2\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 179px;\"\u003e\n \u003cp\u003e30.39\u0026plusmn;7.52\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 145px;\"\u003e\n \u003cp\u003e24.20\u0026plusmn;5.23\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 114px;\"\u003e\n \u003cp\u003e0.001\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 122px;\"\u003e\n \u003cp\u003eT3\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 179px;\"\u003e\n \u003cp\u003e43.48\u0026plusmn;11.16\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 145px;\"\u003e\n \u003cp\u003e41.46\u0026plusmn;8.00\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 114px;\"\u003e\n \u003cp\u003e0.466\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n\u003c/table\u003e\n\u003cp\u003eValues expressed as mean \u0026plusmn; standard deviation.HR: heart rate; MAP: mean arterial pressure;BIS, bispectral index;\u003c/p\u003e\n\u003cp\u003ePaCO2: partial pressure of carbon dioxide partial pressure;PaO2, partial pressure of oxygen in arterial blood;T0: before one-lung ventilation; T1: 15 min after one-lung ventilation; T2: 1 h after onelung ventilation; T3: 20 min after resuming two-lung ventilation.*P \u0026lt; 0.05 versus T0,#P\u0026lt;0.05 vs. control group.\u003c/p\u003e\n\u003cp\u003eTable 3 Comparison of perioperative anesthetic drug consumption\u003c/p\u003e\n\u003ctable border=\"1\" cellspacing=\"0\" cellpadding=\"0\" width=\"620\"\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 300px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 121px;\"\u003e\n \u003cp\u003eEsketamine\u003c/p\u003e\n \u003cp\u003e(n = 25)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 129px;\"\u003e\n \u003cp\u003eControl\u003c/p\u003e\n \u003cp\u003e(n = 25)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 69px;\"\u003e\n \u003cp\u003ep value\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 300px;\"\u003e\n \u003cp\u003e\u0026nbsp;remifentanil (mg)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 121px;\"\u003e\n \u003cp\u003e1.32\u0026plusmn;0.28\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 129px;\"\u003e\n \u003cp\u003e1.86\u0026plusmn;0.44\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 69px;\"\u003e\n \u003cp\u003e\u0026lt;0.001\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 300px;\"\u003e\n \u003cp\u003e\u0026nbsp;sufentanil (\u0026mu;g)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 121px;\"\u003e\n \u003cp\u003e41(36.56-41.45)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 129px;\"\u003e\n \u003cp\u003e42(36.75\u0026ndash;41.89)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 69px;\"\u003e\n \u003cp\u003e0.045\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 300px;\"\u003e\n \u003cp\u003e\u0026nbsp;propofol (mg)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 121px;\"\u003e\n \u003cp\u003e298\u0026plusmn;48\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 129px;\"\u003e\n \u003cp\u003e430\u0026plusmn;77\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 69px;\"\u003e\n \u003cp\u003e\u0026lt;0.001\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 300px;\"\u003e\n \u003cp\u003eNumber of patients required vasopressor\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 121px;\"\u003e\n \u003cp\u003e2（8%）\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 129px;\"\u003e\n \u003cp\u003e6（24%）\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 69px;\"\u003e\n \u003cp\u003e\u0026lt;0.001\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n\u003c/table\u003e\n\u003cp\u003eThe data are presented as the means \u0026plusmn; SD or the medians (interquartile ranges).\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eTable 4 Postoperative outcome\u003c/strong\u003e\u003c/p\u003e\n\u003ctable border=\"1\" cellspacing=\"0\" cellpadding=\"0\"\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 202px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 136px;\"\u003e\n \u003cp\u003eEsketamine\u003c/p\u003e\n \u003cp\u003e(n = 25)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 126px;\"\u003e\n \u003cp\u003eControl\u003c/p\u003e\n \u003cp\u003e(n = 25)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 104px;\"\u003e\n \u003cp\u003ep value\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd rowspan=\"5\" valign=\"top\" style=\"width: 202px;\"\u003e\n \u003cp\u003ePulmonary complications\u003c/p\u003e\n \u003cp\u003eAtelectasis\u003c/p\u003e\n \u003cp\u003ePneumonia\u003c/p\u003e\n \u003cp\u003eRespiratory failure\u003c/p\u003e\n \u003cp\u003ePleural effusion\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 136px;\"\u003e\n \u003cp\u003e8（32%）\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 126px;\"\u003e\n \u003cp\u003e15（60%）\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 104px;\"\u003e\n \u003cp\u003e0.004\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 136px;\"\u003e\n \u003cp\u003e4（16%）\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 126px;\"\u003e\n \u003cp\u003e8（32%）\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 104px;\"\u003e\n \u003cp\u003e0.002\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 136px;\"\u003e\n \u003cp\u003e1（4%）\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 126px;\"\u003e\n \u003cp\u003e2（8%）\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 104px;\"\u003e\n \u003cp\u003e0.142\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 136px;\"\u003e\n \u003cp\u003e2（8%）\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 126px;\"\u003e\n \u003cp\u003e3（12%）\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 104px;\"\u003e\n \u003cp\u003e0.432\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 136px;\"\u003e\n \u003cp\u003e1（4%）\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 126px;\"\u003e\n \u003cp\u003e2（8%）\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 104px;\"\u003e\n \u003cp\u003e0.306\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 202px;\"\u003e\n \u003cp\u003eARDS\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 136px;\"\u003e\n \u003cp\u003e0（0%）\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 126px;\"\u003e\n \u003cp\u003e0（0%）\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 104px;\"\u003e\n \u003cp\u003e1\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 202px;\"\u003e\n \u003cp\u003eThoracic drainagetube removal time (days)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 136px;\"\u003e\n \u003cp\u003e3.42 \u0026plusmn; 1.31\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 126px;\"\u003e\n \u003cp\u003e3.36 \u0026plusmn; 1.21\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 104px;\"\u003e\n \u003cp\u003e0.582\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 202px;\"\u003e\n \u003cp\u003ePostoperativehospital stay (d)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 136px;\"\u003e\n \u003cp\u003e7.76 \u0026plusmn; 1.35\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 126px;\"\u003e\n \u003cp\u003e8.45 \u0026plusmn; 1.66\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 104px;\"\u003e\n \u003cp\u003e0.045\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n\u003c/table\u003e\n\u003cp\u003eData are mean \u0026plusmn; SD, median [IQR] or n (%).PPC, postoperative pulmonary complication; ARDS, acute respiratory distress syndrome\u003c/p\u003e"},{"header":"Discussion","content":"\u003cp\u003eThis randomized trial evaluated the effects of esketamine on oxygenation and Qs/Qt in patients undergoing thoracoscopic radical resection for lung cancer. The study demonstrated that continuous infusion of esketamine significantly improved arterial oxygenation (PaO₂/FiO₂) during OLV, reduced Qs/Qt, enhanced dynamic lung compliance, and resulted in fewer postoperative pulmonary complications.\u003c/p\u003e\u003cp\u003eOLV can promote the release of oxygen free radicals and inflammatory factors, leading to oxidative stress and pulmonary inflammatory response, as well as damage to alveolar epithelial cells and vascular endothelial cells, resulting in increased pulmonary capillary permeability, alveolar and interstitial edema bleeding and inflammatory cell infiltration,ultimately leading to lung injury and worsening hypoxemia[\u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e9\u003c/span\u003e, \u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e10\u003c/span\u003e].PaO2/FiO2 reflects the gas exchange function of the lungs; the larger PaO2/FiO2 presents better lung ventilation function.This study found that PaO2/FiO2 ratios decreased significantly in both groups during one-lung ventilation. Compared with Group C, patients in Group E exhibited signific-antly higher PaO2/FiO2 during OLV and after transitioning back to double-lung ventilation.Esketamine can reduce perioperative lung injury in patients undergoing surgery by repressing inflammatory responses and oxidative stress to promote lung function and decrease adverse effects of the surgery[\u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e11\u003c/span\u003e].\u003c/p\u003e\u003cp\u003eThe baseline characteristics and preoperative pulmonary function test results were comparable between the two patient groups.All patients underwent fiberoptic bronchoscopy-guided adjustment of the double-lumen endotracheal tube following intubation.During OLV, we maintain appropriate airway pressure and peripheral blood oxygen saturation. Consequently, the impact on oxygenation caused by imperfect alignment of the double-lumen tube is eliminated.Previous studies have revealed that high-\u0026shy;dose esketamine causes anaesthesia and is associated with side effects such as hallucinations and delirium[\u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e12\u003c/span\u003e].Our study employed an induction dose of 0.5 mg/kg and a maintenance dose of 0.15 mg/kg/h, which effectively maintained hemodynamic stability during surgery, provided analgesia, and reduced the incidence of adverse psychological reactions [\u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e13\u003c/span\u003e].\u003c/p\u003e\u003cp\u003eDuring OLV, the non-ventilated lung collapses completely but continues to receive a portion of cardiac output from the right ventricle, resulting in pulmonary shunting.The Increased of intrapulmonary shunting can lead to unilateral hypoxemia, hypoxic pulmonary vasoconstriction, and and lung recruitment after single lung during OLV,.which can cause the production and release of alveolar epithelial cytokines such as tumor necrosis factor and interleukin-6, increases capillary permeability, and severely causes alveolar edema, thereby exacerbating lung injury[\u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e14\u003c/span\u003e].Animal studies indicate[\u003cspan citationid=\"CR14\" class=\"CitationRef\"\u003e15\u003c/span\u003e] that continuous infusion of ketamine during one-lung ventilation reduces intrapulmonary shunt fraction.Our study found that the Qs/Qt was significantly reduced in Group E during surgery.Esketamine may reduce intrapulmonary shunting and improve intraoperative oxygenation in patients undergoing one-lung ventilation by relaxing airway smooth muscle and relieving bronchial and small airway spasm [\u003cspan citationid=\"CR15\" class=\"CitationRef\"\u003e16\u003c/span\u003e].Furthermore, studies by Eber et al. [\u003cspan citationid=\"CR16\" class=\"CitationRef\"\u003e17\u003c/span\u003e] indicate that the intraoperative use of esketamine reduces propofol consumption, consistent with the findings of this study.Propofol exhibits a dose-dependent inhibitory effect on HPV, and reducing its dosage may also help decrease Qs/Qt and improve oxygenation [\u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e7\u003c/span\u003e].\u003c/p\u003e\u003cp\u003eLung compliance refers to the response of lung volume to unit changes in pressure, serving as a sensitive indicator of lung injury and ventilation. Higher lung compliance may reflect lower respiratory tract reactivity to some extent. Improving lung compliance, reducing respiratory work, and promoting gas exchange are crucial in patients undergoing general anesthesia[\u003cspan citationid=\"CR17\" class=\"CitationRef\"\u003e18\u003c/span\u003e].A previous study demonstrated that ketamine administered to ICU patients for pain relief increases lung compliance and reduces airway resistance [\u003cspan citationid=\"CR18\" class=\"CitationRef\"\u003e19\u003c/span\u003e].Children with refractory bronchospasm undergoing mechanical ventilation demonstrated favorable responses following continuous infusion of ketamine, with significant improvements in lung compliance and oxygenation [\u003cspan citationid=\"CR19\" class=\"CitationRef\"\u003e20\u003c/span\u003e].In our study,We found that compared with Group C, Group E exhibited a significant increase in Cdyn and a decrease in Pplat and Ppeak during 1 hour of one-lung ventilation.This may be because esketamine is a potential bronchodilator[\u003cspan citationid=\"CR20\" class=\"CitationRef\"\u003e21\u003c/span\u003e], which may help promote the clearance of respiratory secretions and mucus[\u003cspan citationid=\"CR21\" class=\"CitationRef\"\u003e22\u003c/span\u003e].\u003c/p\u003e\u003cp\u003eAdequate hemodynamics can maintain an appropriate ventilation-perfusion ratio, thereby enhancing oxygenation.In this study, compared with group C, group E exhibited hemodynamic stability, elevated mean arterial pressure, and reduced vasoactive drug usage.Esketamine reduces cardiac parasympathetic activity by blocking parasympathetic Na⁺ channels in the brainstem and inhibiting catecholamine reuptake, thereby elevating heart rate and blood pressure [\u003cspan citationid=\"CR22\" class=\"CitationRef\"\u003e23\u003c/span\u003e], which helps maintain hemodynamic stability in patients.Additionally, esketamine possesses sedative and analgesic effects, and its supplemental administration undoubtedly deepens anesthesia. However, the BIS values in group E patients consistently exceeded those in group C throughout the study, potentially related to esketamine's inhibition of NMDA receptors and hyperpolarization-activated cyclic nucleotide-gated (HCN) channels [\u003cspan citationid=\"CR23\" class=\"CitationRef\"\u003e24\u003c/span\u003e].\u003c/p\u003e\u003cp\u003eEffective postoperative pain management is crucial in the ERAS protocol, as pain can reduce tidal volume and impair the ability to effectively clear secretions and sputum through coughing.Esketamine is an NMDA receptor antagonist with agonist effects on delta and mu opioid receptors. It provides analgesia and prevents hyperalgesia[\u003cspan citationid=\"CR24\" class=\"CitationRef\"\u003e25\u003c/span\u003e].The reduced incidence of group E atelectasis observed in our study can be attributed to decreased coughing and purulent sputum production.\u003c/p\u003e\u003cp\u003eOur study has certain limitations. First, inhalation anesthetics are currently believed to influence intrapulmonary shunting during OLV. To minimize the effects of inhalation anesthetics, we maintained anesthesia with the lowest possible concentration of sevoflurane in both groups. Nevertheless, we cannot rule out its potential impact on intrapulmonary shunting.Second, this study was a single-center randomized controlled trial with a small sample size. Some indicators showed only trends and did not yield statistically significant results. Future research should involve multicenter studies with larger sample sizes.Finally, both groups received a fixed dose of opioids to rule out differences in respiratory depression caused by varying opioid doses. Further evaluation is warranted regarding the efficacy of esketamine in patient-controlled analgesia (PCA). Esketamine's opioid-sparing effect [\u003cspan citationid=\"CR25\" class=\"CitationRef\"\u003e26\u003c/span\u003e] may offer additional benefits for respiratory function and postoperative outcomes following lung surgery.\u003c/p\u003e"},{"header":"Conclusion","content":"\u003cp\u003eIn summary, Continuous infusion of esketamine during anesthesia in thoracoscopic surgery patients improves oxygenation (PaO\u003csub\u003e2\u003c/sub\u003e/FiO\u003csub\u003e2\u003c/sub\u003e) during OLV and reduces the Qs/Qt. It also decreases Ppeak and Pplat while increasing Cdyn. This approach reduces postoperative complication rates and shortens hospital stays, offering a novel pathway for perioperative lung protection and promoting patient recovery.\u003c/p\u003e"},{"header":"Declarations","content":"\u003cp\u003e The manuscript reporting adheres to CONSORT guidelines.\u003c/p\u003e\u003cp\u003e\u003cstrong\u003eEthics approval and consent to participate\u003c/strong\u003e\u003cp\u003e This study was conducted in accordance with the Declaration of Helsinki and Good Clinical Practice guidelines. Ethical approval was obtained from the Research Ethics Committee of The First Affiliated Hospital of Henan University(reference number: 2024-03-070) on August 28, 2024. The trial was registered online on December 09 2024 in the Chinese Clinical Trial Registry(ChiCTR2400093592, \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://www.chictr.org.cn\u003c/span\u003e\u003cspan address=\"https://www.chictr.org.cn\" targettype=\"URL\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e), and the first patient was enrolled on December 15, 2024. Written informed consent was obtained from all participants in this study.\u003c/p\u003e\u003c/p\u003e\u003cp\u003e\u003cstrong\u003eConsent for publication\u003c/strong\u003e\u003cp\u003eNot applicable.\u003c/p\u003e\u003c/p\u003e\u003ch2\u003eFunding\u003c/h2\u003e\u003cp\u003eHenan Provincial Natural Science Foundation of China(NO.252300420120);Henan Provincial Science and Technology Program Projects(NO.242102310389)\u003c/p\u003e\u003ch2\u003eAuthor Contribution\u003c/h2\u003e\u003cp\u003eFCY contributed to writing the original draft, reviewing and editing,conceptualization, visualization, methodology, project administration, formal analysis, and investigation. HXD and SKM participated in investigation,writing review and editing, data curation, and resources. LJ wasresponsible for data curation, formal analysis, investigation, visualization,and software. ZXZ handled conceptualization, writing review and editing,visualization, methodology, supervision, validation, resources, project administration, and formal analysis.\u003c/p\u003e\u003ch2\u003eAcknowledgement\u003c/h2\u003e\u003cp\u003eWe would like to acknowledge the hard and dedicated work of all the staff that implemented the intervention and evaluation components of the study.\u003c/p\u003e\u003ch2\u003eData Availability\u003c/h2\u003e\u003cp\u003eAll data generated or analysed during this study are included in this article.Further enquiries can be directed to the corresponding author.\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\u003cli\u003e\u003cspan\u003eHuang SQ, Zhang J, Zhang XX, Liu L, Yu Y, Kang XH, Wu XM, Zhu SM. Can Dexmedetomidine Improve Arterial Oxygenation and Intrapulmonary Shunt during One-lung Ventilation in Adults Undergoing Thoracic Surgery? A Meta-analysis of Randomized, Placebo-controlled Trials. Chin Med J. 2017;130(14):1707\u0026ndash;14. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.4103/0366-6999.209891\u003c/span\u003e\u003cspan address=\"10.4103/0366-6999.209891\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eBlank RS, Colquhoun DA, Durieux ME, Kozower BD, McMurry TL, Bender SP, Naik BI. Management of One-lung Ventilation: Impact of Tidal Volume on Complications after Thoracic Surgery. Anesthesiology. 2016;124(6):1286\u0026ndash;95. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1097/ALN.0000000000001100\u003c/span\u003e\u003cspan address=\"10.1097/ALN.0000000000001100\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eChoi YS, Shim JK, Na S, Hong SB, Hong YW, Oh YJ. Pressure-controlled versus volume-controlled ventilation during one-lung ventilation in the prone position for robot-assisted esophagectomy. Surg Endosc. 2009;23(10):2286\u0026ndash;91. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1007/s00464-008-0310-5\u003c/span\u003e\u003cspan address=\"10.1007/s00464-008-0310-5\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eXia R, Yin H, Xia ZY, Mao QJ, Chen GD, Xu W. Effect of intravenous infusion of dexmedetomidine combined with inhalation of isoflurane on arterial oxygenation and intrapulmonary shunt during single-lung ventilation. Cell Biochem Biophys. 2013;67(3):1547\u0026ndash;50. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1007/s12013-013-9659-8\u003c/span\u003e\u003cspan address=\"10.1007/s12013-013-9659-8\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eLee 5, Kim SH, Lee N, Ban CY, M. G., Oh YJ. Effects of dexmedetomidine on oxygenation and lung mechanics in patients with moderate chronic obstructive pulmonary disease undergoing lung cancer surgery: A randomised double-blinded trial. Eur J Anaesthesiol. 2016;33(4):275\u0026ndash;82. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1097/EJA.0000000000000405\u003c/span\u003e\u003cspan address=\"10.1097/EJA.0000000000000405\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eQiao D, Liu W, Xue H, Liu R, Gao Y, Dong J, Wu W, Feng J, Li M, Yao L. Comparison of the effects of esketamine/midazolam and remifentanil/midazolam on respiratory mechanics in mechanically ventilated patients with acute respiratory distress syndrome. BMC Anesthesiol. 2025;25(1):339. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1186/s12871-025-03211-x\u003c/span\u003e\u003cspan address=\"10.1186/s12871-025-03211-x\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eLumb AB, Slinger P. Hypoxic pulmonary vasoconstriction: physiology and anesthetic implications. Anesthesiology. 2015;122(4):932\u0026ndash;46. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1097/ALN.0000000000000569\u003c/span\u003e\u003cspan address=\"10.1097/ALN.0000000000000569\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eZhang S, Zhou Y, Zhao L, Tian X, Jia M, Gu X, Feng N, An R, Yang L, Zheng G, Li J, Guo H, Fan R, Pei J. κ-opioid receptor activation protects against myocardial ischemia-reperfusion injury via AMPK/Akt/eNOS signaling activation. Eur J Pharmacol. 2018;833:100\u0026ndash;8. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1016/j.ejphar.2018.05.043\u003c/span\u003e\u003cspan address=\"10.1016/j.ejphar.2018.05.043\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003ePerbet S, Verdonk F, Godet T, Jabaudon M, Chartier C, Cayot S, Guerin R, Morand D, Bazin JE, Futier E, Pereira B, Constantin JM. Low doses of ketamine reduce delirium but not opiate consumption in mechanically ventilated and sedated ICU patients: A randomised double-blind control trial. Anaesth Crit care pain Med. 2018;37(6):589\u0026ndash;95. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1016/j.accpm.2018.09.006\u003c/span\u003e\u003cspan address=\"10.1016/j.accpm.2018.09.006\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eTu W, Yuan H, Zhang S, Lu F, Yin L, Chen C, Li J. Influence of anesthetic induction of propofol combined with esketamine on perioperative stress and inflammatory responses and postoperative cognition of elderly surgical patients. Am J translational Res. 2021;13(3):1701\u0026ndash;9.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eWilliamson D, Turkoz I, Wajs E, Singh JB, Borentain S, Drevets WC. Adverse Events and Measurement of Dissociation After the First Dose of Esketamine in Patients With TRD. Int J Neuropsychopharmacol. 2023;26(3):198\u0026ndash;206. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1093/ijnp/pyac081\u003c/span\u003e\u003cspan address=\"10.1093/ijnp/pyac081\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eZhang J, Ma Q, Li W, Li X, Chen X. S-Ketamine attenuates inflammatory effect and modulates the immune response in patients undergoing modified radical mastectomy: A prospective randomized controlled trial. Front Pharmacol. 2023;14:1128924. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.3389/fphar.2023.1128924\u003c/span\u003e\u003cspan address=\"10.3389/fphar.2023.1128924\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eGuo W, Jin XJ, Yu J, Liu Y, Zhang JP, Yang DW, Zhang L, Guo JR. Effects of stellate ganglion block on the peri-operative vasomotor cytokine content and intrapulmonary shunt in patients with esophagus cancer. Asian Pac J cancer prevention: APJCP. 2014;15(21):9505\u0026ndash;9. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.7314/apjcp.2014.15.21.9505\u003c/span\u003e\u003cspan address=\"10.7314/apjcp.2014.15.21.9505\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eLumb PD, Silvay G, Weinreich AI, Shiang H. A comparison of the effects of continuous ketamine infusion and halothane on oxygenation during one-lung anaesthesia in dogs. Can Anaesth Soc J. 1979;26(5):394\u0026ndash;401. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1007/BF03006454\u003c/span\u003e\u003cspan address=\"10.1007/BF03006454\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eZou H, Wang LX, Wang M, Cheng C, Li S, Shen Q, Fang L, Liu R. (2019). MTOR-Mediated Autophagy Is Involved in the Protective Effect of Ketamine on Allergic Airway Inflammation. Journal of immunology research, 2019, 5879714. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1155/2019/5879714\u003c/span\u003e\u003cspan address=\"10.1155/2019/5879714\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eEberl S, Koers L, van Hooft J, de Jong E, Hermanides J, Hollmann MW, Preckel B. The effectiveness of a low-dose esketamine versus an alfentanil adjunct to propofol sedation during endoscopic retrograde cholangiopancreatography: A randomised controlled multicentre trial. Eur J Anaesthesiol. 2020;37(5):394\u0026ndash;401. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1097/EJA.0000000000001134\u003c/span\u003e\u003cspan address=\"10.1097/EJA.0000000000001134\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eWang X, Gong C, Zhang Y, Li S, Huang L, Chen L. Effects of dexmedetomidine on dynamic lung compliance in general anesthesia with desflurane: A randomized controlled study. Heliyon. 2023;9(6):e16672. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1016/j.heliyon.2023.e16672\u003c/span\u003e\u003cspan address=\"10.1016/j.heliyon.2023.e16672\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eWang X, Gong C, Zhang Y, Li S, Huang L, Chen L. Effects of dexmedetomidine on dynamic lung compliance in general anesthesia with desflurane: A randomized controlled study. Heliyon. 2023;9(6):e16672. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1016/j.heliyon.2023.e16672\u003c/span\u003e\u003cspan address=\"10.1016/j.heliyon.2023.e16672\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eYoussef-Ahmed MZ, Silver P, Nimkoff L, Sagy M. Continuous infusion of ketamine in mechanically ventilated children with refractory bronchospasm. Intensive Care Med. 1996;22(9):972\u0026ndash;6. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1007/BF02044126\u003c/span\u003e\u003cspan address=\"10.1007/BF02044126\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eWilliamson D, Turkoz I, Wajs E, Singh JB, Borentain S, Drevets WC. Adverse Events and Measurement of Dissociation After the First Dose of Esketamine in Patients With TRD. Int J Neuropsychopharmacol. 2023;26(3):198\u0026ndash;206. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1093/ijnp/pyac081\u003c/span\u003e\u003cspan address=\"10.1093/ijnp/pyac081\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eOdor PM, Bampoe S, Gilhooly D, Creagh-Brown B, Moonesinghe SR. (2020). Perioperative interventions for prevention of postoperative pulmonary complications: systematic review and meta-analysis. BMJ (Clinical research ed.), 368, m540. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1136/bmj.m540\u003c/span\u003e\u003cspan address=\"10.1136/bmj.m540\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eEberl S, Koers L, van Hooft JE, de Jong E, Schneider T, Hollmann MW, Preckel B. Sedation with propofol during ERCP: is the combination with esketamine more effective and safer than with alfentanil? Study protocol for a randomized controlled trial. Trials. 2017;18(1):472. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1186/s13063-017-2197-8\u003c/span\u003e\u003cspan address=\"10.1186/s13063-017-2197-8\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eZanos P, Moaddel R, Morris PJ, Riggs LM, Highland JN, Georgiou P, Pereira EFR, Albuquerque EX, Thomas CJ, Zarate CA Jr, Gould TD. Ketamine and Ketamine Metabolite Pharmacology: Insights into Therapeutic Mechanisms. Pharmacol Rev. 2018;70(3):621\u0026ndash;60. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1124/pr.117.015198\u003c/span\u003e\u003cspan address=\"10.1124/pr.117.015198\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eSt\u0026eacute;phan F, Boucheseiche S, Hollande J, Flahault A, Cheffi A, Bazelly B, Bonnet F. Pulmonary complications following lung resection: a comprehensive analysis of incidence and possible risk factors. Chest. 2000;118(5):1263\u0026ndash;70. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1378/chest.118.5.1263\u003c/span\u003e\u003cspan address=\"10.1378/chest.118.5.1263\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eQiu D, Wang XM, Yang JJ, Chen S, Yue CB, Hashimoto K, Yang JJ. Effect of Intraoperative Esketamine Infusion on Postoperative Sleep Disturbance After Gynecological Laparoscopy: A Randomized Clinical Trial. JAMA Netw open. 2022;5(12):e2244514. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1001/jamanetworkopen.2022.44514\u003c/span\u003e\u003cspan address=\"10.1001/jamanetworkopen.2022.44514\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e.\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":false,"isAuthorSuppliedPdf":false,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":false,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"bmc-anesthesiology","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"bane","sideBox":"Learn more about [BMC Anesthesiology](http://bmcanesthesiol.biomedcentral.com/)","snPcode":"","submissionUrl":"https://www.editorialmanager.com/bane","title":"BMC Anesthesiology","twitterHandle":"BMC_series","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"em","reportingPortfolio":"BMC Series","inReviewEnabled":true,"inReviewRevisionsEnabled":true},"keywords":"One-lung ventilation, Esketamine, Oxygenation, Pulmonary shunt","lastPublishedDoi":"10.21203/rs.3.rs-7593019/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-7593019/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003e\u003cstrong\u003eBackground：\u003c/strong\u003eOne-lung ventilation (OLV) is a commonly used mechanical ventilation technique in open chest surgery, which can lead to serious complications.This study aims to investigate the effects of esketamine on oxygenation (PaO₂/FiO₂) and intrapulmonary shunt (Qs/Qt) during OLV in patients undergoing thoracic surgery.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eMethods：\u003c/strong\u003eFifty patients were randomly allocated to either esketamine group (group E) or control group (group C).Group E received 0.5 mg/kg esketamine.The control group received normal saline. blood samples were takento analyze arterial blood gasses during four time periods at bfore anesthesia induction (T0),30 min after OLV(T1),60 min after OLV(T2) and 20 min after reinstitution of two-lung ventilation(T3).PaO₂/FiO₂, Qs/Qt , heart rate, mean arterial pressure(MAP),parameters mechanics and postoperative pulmonary complication incidence values were recorded at these time points.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eResults:\u003c/strong\u003eCompared with the group C, the PaO2/FiO2 ratio was significantly increased, and the Qs/Qt were significantly decreased in the group E at T1, T2, and T3 (all p\u0026lt;0.05).At T1 and T2, the Ppeak and Pplat in the group E were significantly lower than those in the group C, while the Cdyn value was significantly higher than that in\u003c/p\u003e\n\u003cp\u003ethe group C (all P \u0026lt; 0.05).The incidence of atelectasis in the group E was significantly lower than that in the group C (16% vs. 32%, P=0.002). However, there was no statistically significant difference in the incidence of any other PPCs episodes between the two groups.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eConclusion：\u003c/strong\u003eIntravenous administration of esketamine during lung resection improves oxygenation status (PaO₂/FiO₂), reduces pulmonary artery shunt fraction (Qs/Qt), enhances pulmonary artery compliance (Cdyn), and decreases the incidence of postoperative pulmonary complications.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eTrial registration：\u003c/strong\u003eThe trial was registered at the Chinese Clinical Trials Registry (www.chictr.org.cn, registration number: ChiCTR2400093592, date of registration: 09/12/2024).\u003c/p\u003e","manuscriptTitle":"Effect of intravenous esketamine on oxygenation and intrapulmonary shunting during One-lung ventilation in thoracoscopic surgery: A Randomized Controlled Trial","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2025-11-17 06:33:10","doi":"10.21203/rs.3.rs-7593019/v1","editorialEvents":[{"type":"communityComments","content":0},{"type":"reviewerAgreed","content":"283773055433067190714360441011717709995","date":"2026-05-05T05:50:16+00:00","index":"hide","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2025-11-17T19:27:27+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"206384836110417918143388999795119334864","date":"2025-11-14T10:05:28+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"132663743389712836807511201345175973673","date":"2025-11-12T10:25:39+00:00","index":"hide","fulltext":""},{"type":"reviewersInvited","content":"","date":"2025-11-05T09:08:54+00:00","index":"","fulltext":""},{"type":"editorAssigned","content":"","date":"2025-10-29T15:30:06+00:00","index":"","fulltext":""},{"type":"editorInvited","content":"","date":"2025-10-06T07:35:38+00:00","index":"","fulltext":""},{"type":"checksComplete","content":"","date":"2025-10-04T02:30:10+00:00","index":"","fulltext":""},{"type":"submitted","content":"BMC Anesthesiology","date":"2025-10-04T02:26:50+00:00","index":"","fulltext":""}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"bmc-anesthesiology","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"bane","sideBox":"Learn more about [BMC Anesthesiology](http://bmcanesthesiol.biomedcentral.com/)","snPcode":"","submissionUrl":"https://www.editorialmanager.com/bane","title":"BMC Anesthesiology","twitterHandle":"BMC_series","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"em","reportingPortfolio":"BMC Series","inReviewEnabled":true,"inReviewRevisionsEnabled":true}}],"origin":"","ownerIdentity":"968d21be-c3e2-4deb-b9c4-56f2bd88a775","owner":[],"postedDate":"November 17th, 2025","published":true,"recentEditorialEvents":[{"type":"reviewerAgreed","content":"283773055433067190714360441011717709995","date":"2026-05-05T05:50:16+00:00","index":144,"fulltext":""}],"rejectedJournal":[],"revision":"","amendment":"","status":"under-review","subjectAreas":[],"tags":[],"updatedAt":"2025-11-17T06:33:10+00:00","versionOfRecord":[],"versionCreatedAt":"2025-11-17 06:33:10","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-7593019","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-7593019","identity":"rs-7593019","version":["v1"]},"buildId":"XKTyCvWXoU3ODBz1xrDgd","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}