Impact of 1-week preoperative auto-CPAP treatment on postoperative outcomes in patients undergoing heart valve replacement surgery: a prospective randomized controlled trial

Impact of 1-week preoperative auto-CPAP treatment on postoperative outcomes in patients undergoing heart valve replacement surgery: a prospective 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 Impact of 1-week preoperative auto-CPAP treatment on postoperative outcomes in patients undergoing heart valve replacement surgery: a prospective randomized controlled trial Ning Ding, Mei Su, Xu Qi, Buqing Ni, Shijiang Zhang, Xilong Zhang This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-1391530/v1 This work is licensed under a CC BY 4.0 License Status: Posted Version 1 posted You are reading this latest preprint version Abstract Whether preoperative continuous positive airway pressure (CPAP) treatment improves postoperative outcomes in patients undergoing cardiac valve replacement (CVR) remains unknown. This tudy was to evaluate the effects of 1-week perioperative auto-continuous positive airway pressure (CPAP) treatment on postoperative heart and pulmonary outcomes in patients with obstructive sleep apnea (OSA) and valvular heart disease. Thirty-two patients with OSA and valvular heart disease were randomly assigned to 1-week CPAP (n = 15) group and non-CPAP treatments (n = 17) group. After the treatment, all patients underwent CVR surgery. The length of ICU and hospital stays, postoperative cardiac and respiratory complications were assessed and compared between the two groups. The results showed there was no significant difference in the baseline characteristics between the CPAP and non-CPAP treatment groups. The length of postoperative ICU and hospital stays, as well as the duration of mechanical ventilation were significantly reduced in the CPAP treatment group compared to the non-CPAP treatment group; however, there were no significant differences in cardiac complications (postoperative arrhythmias, pacemaker use, first dose of dopamine in the ICU, and first dose of dobutamine in the ICU), and respiratory complications (reintubation and pneumonia). We conclused that in patients underwent CVR, preoperative use of auto-CPAP for OSA significantly decreased the duration of mechanical ventilation, and postoperative stays in the ICU and hospital, but did not have an association with postoperative arrhythmias, pacemaker use, reintubation, or pneumonia. obstructive sleep apnea CPAP cardiac valve replacement postoperative complication Figures Figure 1 Introduction Obstructive sleep apnea (OSA) is one of the most common sleep disorders in adults, with reported prevalence rates between 16% and 84% 1,2 . OSA is associated with increased all-cause and cardiovascular mortality risks, as well as the incidence of hypertension 3 , coronary heart disease, heart failure and postoperative cardiovascular events (sudden cardiac death, atrial fibrillation, congestive heart failure, and myocardial injury) 4 – 6 . In our previous study we reported that OSA is common in patients undergoing cardiac valve replacement (CVR). Moreover, preoperative OSA is associated with an increased mechanical ventilation duration and a longer intensive care unit (ICU) stay, as well as a higher rate of postoperative pacemaker use 7 . Continuous positive airway pressure (CPAP) is the mainstay treatment for patients with OSA. A previous study showed that the postoperative complications are increased in patients with untreated OSA who undergo general and vascular surgery 8 . Although it is well-established that perioperative CPAP significantly reduces the postoperative apnea-hypopnea index (AHI) and pulmonary complications, improves the oxygen saturation, and shortens the length of hospital stay following cardiac and non-cardiac surgery 9 – 12 ; however, it is not completely clear whether perioperative CPAP improves the postoperative outcomes in patients undergoing CVR surgery. The objective of this study was to determine if perioperative CPAP treatment could inprove postoperatienve adverse events, including decreasing the lengths of stay (hospital, preoperative, postoperative, and ICU), cardiac complications (postoperative arrhythmias, pacemaker use, first dose of dopamine in the ICU, and first dose of dobutamine in the ICU), and respiratory complications (reintubation, pneumonia, and duration of mechanical ventilation). Materials And Methods Patients and study design. Between January 2018 and December 2019, a total of 223 patients with rheumatic valvular heart disease (18–75 years of age) undergoing CVR were screened for OSA using ApneaLink™ Air (ResMed Corp., Australia) in the first 3 days of hospitalization. Patients with OSA who agreed to participate in our study underwent an overnight polysomnography (PSG) the next day. The patients with an AHI ≥ 5/h were randomly assigned to the CPAP (n = 17) and non-CPAP treatment groups (n = 17). Patients in the CPAP treatment group received CPAP + basic treatment for 7 d (15 patients completed the 7-d treatment). Patients in the non-CPAP treatment group received basic treatment for 7 d. All patients underwent CVR surgery 1 week after completing treatment. The patients were admitted to the ICU and received mechanical ventilation postoperatively. The postoperative PSG was performed 1–3 d prior to hospital discharge. The inclusion criteria were as follows: (1) 18 − 75 years of age; (2) diagnosed with rheumatic valvular heart disease; (3) diagnosed with OSA (AHI > = 5/h). (4) received heart valve replacement surgery; and (5) signed informed consent. The exclusion criteria were as follows: (1) history of stroke or clinical signs of peripheral or central nervous system disorders; (2) previously known congenital heart disease, coronary heart disease, myocardial infarction, dilated cardiomyopathy, or hypertrophic cardiomyopathy; and (3) chronic obstructive pulmonary disease or a history of asthma. Figure 1 shows the study design flow chart. Randomized method: Random sequence numbers (1 − 34) were generated using Excel software by a statistician who did not otherwise take part in this study. According to the order of enrollment, the random sequence number was used one-by-one. Odd numbers were assigned to the CPAP treatment group and even numbers were assigned to the non-CPAP treatment group. The statistician and the data collector were blinded to interventions and the care providers were blinded to outcome parameters. Preoperative basic treatment included oxygen and optimal medications. Oxygen therapy was administered when a patient had a pulse oxygen saturation (SpO 2 ) < 90%. The optimal medication therapy included digoxin, diuretics, nitrates, an angiotensin-converting enzyme inhibitor/ angiotensin receptor blocker, and a β-blocker. The diagnosis of rheumatic valvular heart disease was based on the 2012 criteria for the diagnosis of rheumatic fever and rheumatic heart disease, as follows 13 : a primary episode of rheumatic fever or current clinical rheumatic heart disease as featured and typical rheumatic valvular lesions were examined by Doppler echocardiography. Baseline clinical evaluation. The preoperative physical examinations and heart function evaluations were performed by the same physician. Patient height, weight, and body mass index (BMI [weight in kg/height in m 2 ]) were recorded. The New York Heart Association (NYHA) classification was determined. Atrial fibrillation was detected by 12-lead electrocardiography. Two-dimensional Doppler echocardiography was performed to assess left ventricular ejection fraction (LVEF). Valvular disease was assessed by echocardiography and confirmed by pathologic evaluation postoperatively. The 6-min walking test (6MWT) was performed within 3 d after hospital admission, as we previously reported 7 , 14 . Polysomnography. The Epworth Sleepiness Scale (ESS) score was recorded before the sleep study to assess daytime sleepiness. The sleep study was an unattended overnight PSG (Alice 6 LDx System; Respironics, Inc., Netherlands) pre- and postoperatively. We used the 2012 standards of the American Academy of Sleep Medicine (AASM) 15 to score sleep apnea (SA) types and associated events, as described previously 7 : obstructive apnea, > 90% decrease in airflow with continued paradoxical chest and abdominal excursion for ≥ 10 s; central apnea, > 90% decrease in airflow as well as complete cessation of chest and abdominal excursion ≥ 10 s; and hypopnea-reduction of airflow, > 50% baseline lasting ≥ 10 s and associated with ≥ 3% desaturation. The AHI was defined as the number of apneic and hypopneic events per h of sleep. An AHI of ≥ 5/h was considered diagnostic for SA. Sleep apnea in which greater than 50% of events were obstructive, was defined as OSA. CPAP treatment. An auto-CPAP (S9 Auto Set; ResMed Corp., Australia) treatment regimen (auto-CPAP, 4–16 cm H 2 O) was offered to the patients in the CPAP treatment group. Recordings with a mean CPAP use > 4 h/night were accepted for each patient 16 . To prevent confounding, all patients used the same CPAP device, and underwent the same clinical evaluations, follow-up assessments, and education regarding OSA and proper CPAP use. All patients had formal mask fitting prior to initiating CPAP therapy. Cardiac valve replacement. CVR was performed in accordance with the American College of Cardiology/American Heart Association guidelines and indications for valve replacement in patients with valvular heart disease 17 . The valve prosthesis type selection was at the discretion of the operating surgeon. All procedures were performed under cardiopulmonary bypass with mild systemic hypothermia (30°C–34°C). Myocardial protection was achieved with cold blood cardioplegia. Postoperative treatment. Patients were admitted to the ICU as soon as possible following CVR surgery. All patients received standard care, including vital sign monitoring, oxygen therapy, mechanical ventilation, and administration of vasoactive agents. All tests or therapies were considered clinically indicated by the surgical team. Postoperative outcome assessment. Lengths of stay (hospital, preoperative, postoperative, and ICU), cardiac complications (postoperative arrhythmias, pacemaker use, first dose of dopamine in the ICU, and first dose of dobutamine in the ICU), and respiratory complications (reintubation, pneumonia, and duration of mechanical ventilation) were assessed and compared between the CPAP and non-CPAP treatment groups. Statistical analysis. The differences between the CPAP and non-CPAP treatment groups of continuous variables were non-normally distributed and tested using the two independent samples Mann-Whitney U test and presented as medians and interquartile ranges. The pre- and postoperative differences for each group were tested by the paired samples Mann-Whitney U test and presented as medians and interquartile ranges. Categorical variables were compared using the chi-square test with a normal approximation or Fisher’s exact test, as appropriate. Two-tailed P values < 0.05 were considered statistically significant. Statistical analyses were performed with SPSS 22.0 statistical software (IBM® SPSS, Inc., Chicago, IL, USA). Ethics approval and consent to participate. The studies were approved by the local institutional review board (Clinical Study Ethics Committee of the First Affiliated Hospital of Nanjing Medical University, No. 2017-SR-040) and registered in ClinicalTrials.gov (ID: NCT03398733, 12/01/2018). The procedures used in this study adhered to the tenets of the Declaration of Helsinki. All participants provided written informed consent when the patients underwent OSA screening. Results Baseline participant characteristics. We screened 232 patients with valvular heart disease, 34 of whom with OSA were enrolled and randomized into the CPAP and non-CPAP treatment groups. Fifteen patients in the CPAP treatment group and 17 patients in the non-CPAP treatment group completed the preoperative treatment and postoperative PSG testing (Figure 1). Table 1 shows a comparison of the baseline characteristics between the CPAP and non-CPAP treatment groups. There was no significant difference with respect to age, BMI, sex, atrial fibrillation, heart valve lesions, NYHA class, medication use, LVEF, 6MWT distance, and arterial blood gas results. Comparisons of sleep data. The total recording time, total sleep time, sleep efficiency, arousal index, sleep stage, AHI, AI, HI, mean SpO 2 , minimal SpO 2 , and oxygen desaturation index (ODI) were recorded or calculated (Table 2). There was no significant difference in the baseline sleep parameters between the CPAP and non-CPAP treatment groups preoperatively. The AHI, AI, and ODI were significantly decreased, and the mean and minimal SpO 2 were significantly increased during CPAP treatment. The AHI, AI, and ODI were significantly decreased postoperatively compared with preoperatively (baseline) in the CPAP and non-CPAP treatment groups. There was no significant difference in the sleep parameters between the CPAP and non-CPAP treatment groups postoperatively. Postoperative complications. Table 3 showesthe lengths of postoperative and ICU stays, and the duration of mechanical ventilation were significantly reduced in the CPAP treatment group compared to the non-CPAP treatment group. There was no significant difference in the length of hospital stay, cardiac complications (postoperative arrhythmias, pacemaker use, first dose of dopamine in the ICU, and first dose of dobutamine in the ICU), and respiratory complications (reintubation and pneumonia). Discussion The present study was a novel, randomized controlled trial to determine the effectiveness of preoperative CPAP in patients with OSA undergoing CVR surgery. OSA is a well-documented risk factor associated with perioperative adverse outcomes. Due to recurrent sleep apnea, intermittent hypoxia, and arousal, postoperative adverse events, such as arrhythmias, myocardial injury, and pulmonary infection, may occur. In the Postoperative Vascular Complications in Unrecognized OSA (POSA) study, Chan and colleagues 6 observed 1,218 patients and concluded that severe OSA was significantly associated with a higher rate of postoperative cardiovascular events. Our previous study showed that patients with OSA were at increased perioperative risk for CVR surgery and associated with overall postoperative recovery, including respiratory insufficiency and a higher rate of postoperative pacemaker use 7 . CPAP treatment during sleep for OSA patients has been shown to significantly reduce AHI and sleepiness, and improve oxygen deficiency 10 . Although treatment of OSA appears to reduce postoperative pulmonary complications, pneumonia, and reintubation rates in patients undergoing major abdominal 9 or heart surgery 18,19 , no definitive data have shown whether preoperative CPAP reduces postoperative complications in patients undergoing CVR surgery. Rennotte et al. 18 reported the effectiveness of CPAP in a case series involving 16 OSA patients. He showed that two OSA patients without preoperative CPAP treatment experienced postoperative adverse events and one patient died, whereas 14 patients with preoperative CPAP treatment had an uneventful postoperative course. Liao et al. 10 developed a randomized controlled trial and confirmed that perioperative auto-CPAP treatment significantly reduced postoperative AHI and improved oxygen saturation in OSA patients. In the present study, the patients in the CPAP group received preoperative auto-CPAP treatment for 1 week. The AHI was decreased and the minimal SpO 2 was increased significantly during CPAP treatment compared with the preoperative values (25 vs. 3 and 74% vs. 88%; both P values < 0.05), thus confirming CPAP treatment was effective in reducing sleep apnea and alleviating nocturnal hypoxemia. A number of studies have shown that postoperative CPAP use significantly reduced the AHI, improves oxygen saturation, and the incidence of postoperative cardiac and pulmonary complications 10-12,16,18-23 . Due to edema in the upper airway, possible fluid shifts, sedation, and changes in sleep position, postoperative patients, especially patients with OSA, are more likely to have airway obstruction. Theoretically, postoperative CPAP use mitigates these issues as needed. Considering the possible lower adherence to CPAP following CVR surgery, we did not evaluate CPAP postoperatively in both the CPAP and control groups. Even though the postoperative AHI in both groups was slightly reduced (25 vs. 19 and 23 vs. 18; both P values < 0.05), the reduced AHI may be associated with surgery rather than CPAP treatment because central sleep apnea can be eliminated after CVR 14 . In the present study patients with preoperative auto-CPAP treatment had a shorter duration of postoperative mechanical ventilation, which may further lead to a reduction in ICU and postoperative hospital stays, thus suggesting that reducing the nocturnal hypoxemia and oxygen debt in OSA patients with preoperative CPAP therapy favored a faster postoperative recovery after CVR surgery. A review reported that CPAP treatment reduced the rate of reintubation and admission into the ICU for invasive ventilation and supportive care 24 . A matched cohort study showed that OSA patients who received CPAP therapy had a reduction in postoperative cardiovascular complications 25 . Kindgen-Milles 26 found that postoperative use of nasal CPAP significantly reduced pulmonary morbidity and the length of hospital stay following surgical repair of thoracoabdominal aortic aneurysms. Our results confirmed these findings in our patients undergoing CVR. CPAP improved upper airway obstruction and increased lung volume, thereby significantly reducing apnea and hypopnea, and the associated hypoxemic and hypercapnic events 11 . In addition, the patients treated with CPAP preoperatively may be more familiar and compliant with postoperative mechanical ventilation, which in turn may lead to mechanical ventilation of short duration. Therefore, perioperative CPAP use may be beneficial in patients with OSA who undergo CVR surgery. The preoperative CPAP treatment did not reduce the incidence of postoperative arrhythmias, pacemaker use, reintubation, and pneumonia in the current study. Zarbock 19 reported that nasal CPAP following cardiac surgery improved arterial oxygenation, reduced the incidence of pulmonary complications, including the pneumonia and reintubation rates, and reduced the readmission rate to the ICU; however, other studies have reported contradictory findings. Altmay 27 observed patients with normal preoperative pulmonary function and CPAP use did not improve lung function after cardiac surgery. Furthermore, short-term CPAP treatment cannot reduce postoperative cardiac arrhythmias 28,29 . There are many factors that induce postoperative arrhythmias, pacemaker use, reintubation, and pneumonia, such as poor cardiac function, hypoxia, and malnutrition. CPAP treatment did not improve all of the aforementioned risk factors. In addition, in our study the small sample size and short time of CPAP treatment were reasons why our data did not reach statistical significance. CPAP adherence in postoperative patients is low. Liao et al. 11 found that the perioperative adherence rate of CPAP was only 45% and another study 30 found only 33% of the patients had > 4 h CPAP treatment; the median adherence was 2.5 h per night. The author speculated that postoperative nausea and vomiting may be associated with reduced CPAP adherence; however, another study did not identify a relationship between the use of CPAP and the increased risk of postoperative nausea and vomiting 31 . With better control of postoperative pain and nausea/vomiting, adherence with CPAP among OSA patients may improve 10 . Our patients had a good adherence with 88% completing > 4 h of CPAP treatment per night. This may be because our patients received short (1 week), preoperative but not postoperative, and in-hospital but not at home CPAP treatment. Limitations There were limitations to our study. First, this study had a short-term clinical observation period, with a 1-week preoperative treatment and 12–15 d postoperative in-hospital outcomes. Although all patients had scheduled follow-up evaluations, we anticipate collecting long-time outcomes in future. Second, even though this was a prospective controlled trial, we did not find significant differences in postoperative arrhythmias, pacemaker use, reintubation, and pneumonia, which may be due to the lack of complications in our study group as a result of the small sample size. Further multicenter and large sample studies are needed. Third, we only observed the effect of preoperative CPAP on postoperative outcomes. Postoperative CPAP use may have a more important role in reduction of the incidence of perioperative cardiac and pulmonary complications. Corollary studies are needed to answer the following important questions: What is the optimal duration of CPAP therapy in OSA patients undergoing CVR surgery? Is CPAP therapy effective preoperatively, postoperatively, or both? Conclusion Preoperative use of auto-CPAP for OSA significantly decreased the duration of mechanical ventilation, and postoperative ICU and hospital stays but failed to show any association with postoperative arrhythmias, pacemaker use, reintubation, and pneumonia. Declarations Availability of data and materials The datasets generated and/or analysed during the current study are not publicly available due to China’s personal data protection laws but are available from the corresponding author on reasonable request. Acknowledgments None. Contributions N.D, S.Z and X.Z designed the study. N.D, M.S, X.Q, B.N contributed data. N.D and X.Z performed the statistical analyses. All authors contributed to manuscript writing and revising. All authors read and approved the final manuscript. Funding: This work was supported by the National Natural Science Foundation of China (Grant No. 82070093) and 511 Take-off Plan (Grant No. JSPH-511C-2018-10). 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Postoperative nausea and vomiting with application of postoperative continuous positive airway pressure after laparoscopic gastric bypass. Obes Surg 20 , 876–880, doi: 10.1007/s11695-008-9741-2 (2010). Tables Table 1. Comparisons of patients’ characteristics. Data are presented as median (interquartile range) or n (%). BMI body mass index, NYHA New York Heart Association, ACEI angiotensin-converting enzyme inhibitors, ARB angiotensin receptor blocker, LVEF left ventricular ejection fraction, 6MWT six-minute walking test. CPAP treatment group (n=15) Non-CPAP treatment group (n=17) p-value Age(yr) 56 (45 - 59) 56 (49 – 61) 0.526 BMI (kg/m 2 ) 28.5 (27.4 – 30.0) 26.8 (25.2 – 29.7) 0.261 Gender 0.946 Male, n (%) 9 (60) 10 (58.8) Female, n (%) 6 (40) 7 (41.2) Heart valve lesions Mitral valve lesions, n (%) 13 (86.7) 15 (88.2) 1.000 Aortic valve lesions, n (%) 9 (60) 10 (58.8) 0.946 Tricuspid valve lesions, n (%) 13 (86.7) 8 (47.1) 0.015 NYHA class 0.513 Ⅱ, n (%) 1 (6.7) 3 (17.6) Ⅲ, n (%) 10 (66.7) 10 (58.8) Ⅳ, n (%) 4 (26.7) 4 (23.5) Atrial fibrillation, n (%) 12 (80) 12 (70.6) 0.691 Hypertension 4 6 0.712 Medication use Digoxin 12 (80) 13 (76.5) 1.000 Diuretics 13 (86.7) 13 (76.5) 0.659 ACEI/ARB 10 (66.7) 9 (52.9) 0.668 β-blockers 8 (53.3) 13 (76.5) 0.266 LVEF (%) 63.4 (58 – 65.4) 62.5 (58.7 – 66.2) 0.737 6MWT distance (m) 426 (369 – 447) 414 (364 – 460) 0.823 Arterial blood gas pH 7.42 (7.36 – 7.44) 7.43 (7.38 – 7.46) 0.502 PaO 2 , mmHg 80 (75 – 86) 81 (72 – 88) 0.823 PaCO 2 , mmHg 47 (42 – 48) 44 (41 – 48) 0.411 Table 2. Comparisons of polysomnography data. Data are presented as median (interquartile range) or n (%). REM rapid eye movement, AHI apnea/hypopnea index, AI apnea index, HI hypopnea index, SpO 2 pulse oxygen saturation, ODI oxygen desaturation index. * p <0.05, between baseline and CPAP treatment; † p-values for within group comparisons, between baseline and postoperative; ‡ p-value for postoperative comparisons between groups. CPAP treatment group (n=15) Non-CPAP treatment group (n=17) p-value‡ Baseline (Preoperative) CPAP treatment Postoperative p-value† Baseline (Preoperative) Postoperative p-value† Total recording time (h) 546 (518 - 574) NA 553 (538 - 573) 0.513 537 (520 - 560) 551 (522 - 576) 0.236 0.655 Total sleep time (h) 388 (366 - 423) NA 383 (369 - 403) 0.074 405 (385 -414) 387 (364 - 409) 0.035 0.455 Sleep efficiency (%) 73 (68 - 76) NA 68 (67 - 75) 0.088 74 (70 - 78) 71 (67 - 75) 0.076 0.350 Arousal index, h -1 21 (18 - 29) NA 17 (13 - 26) 0.005 19 (15 - 25) 15 (11 - 22) 0.003 0.655 Sleep stage N 1 sleep (%) 14 (12 - 19) NA 14 (12 - 16) 0.105 14 (12 - 17) 15 (11 - 16) 0.527 0.551 N 2 sleep (%) 60 (56 - 63) NA 61 (58 - 65) 0.022 58 (56 - 61) 63 (59 - 67) 0.004 0.295 N 3 sleep (%) 8 (6 - 10) NA 9 (8 - 12) 0.030 10 (8 - 12) 7 (5 - 10) 0.055 0.216 REM sleep (%) 18 (14 - 21) NA 17 (12 - 18) 0.237 16 (13 - 20) 13 (11 - 17) 0.046 0.370 AHI, h -1 25 (19 - 33) 3 (1 - 5) * 19 (14 - 28) 0017 23 (17 - 28) 18 (13 - 27) 0.026 0.766 AI, h -1 22 (13 - 25) 0 (0 - 1) * 13 (8 - 18) 0.004 19 (14 - 22) 14 (10 - 20) 0.007 0.551 HI, h -1 4 (3 - 11) 3 (1 - 3) * 6 (5 - 10) 0.101 4 (3 - 6) 5 (3 - 7) 0.408 0.064 Mean SpO 2 (%) 92 (89 - 92) 95 (95 - 97) * 91 (90 - 92) 0.406 92 (90 - 94) 92 (91 - 94) 0.547 0.189 Minimal SpO 2 (%) 74 (70 - 79) 88 (84 – 90) * 77 (73 - 82) 0.104 72 (67 - 77) 74 (70 - 80) 0.016 0.350 ODI, h -1 21 (13 - 27) 2 (1 - 4) * 15 (12 - 25) 0.030 19 (13 - 23) 17 (9 - 21) 0.019 0.502 Table 3. Comparisons of postoperative complications. Data are presented as median (interquartile range) or n (%). ICU intensive care unit. CPAP treatment group (n=15) Non-CPAP treatment group (n=17) p-value Length of stay Length of total hospital stay (d) 25 (22 - 30) 28 (25 - 36) 0.082 Length of preoperative stay (d) 12 (10 - 17) 13 (12 - 17) 0.455 Length of postoperative stay (d) 12 (10 - 14) 15 (12 - 18) 0.044 Length of ICU stay (h) 22 (17 - 55) 36 (29 - 52) 0.040 Cardiac complications Postoperative arrhythmia, n (%) 9 (60) 10 (58.8) 1.000 Pacemaker use, n (%) 2 (13.3) 2 (11.8) 1.000 First dose of dopamine in ICU (µg/kg·min) 4 (2 – 5.5) 4 (3 - 5) 0.682 First dose of dobutamine in ICU (µg/kg·min) 3 (2 - 5) 3 (2 – 4.5) 0.455 Respiratory complications Reintubation 1 (6.7) 2 (11.8) 1.000 Pneumonia 2 (13.3) 3 (17.6) 1.000 Duration of mechanical ventilation (h) 17 (12 - 19) 24 (20 - 34) 0.010 Additional Declarations No competing interests reported. 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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-1391530","acceptedTermsAndConditions":true,"allowDirectSubmit":true,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":97443524,"identity":"aebab4ae-3ae2-4bf8-929b-c74294c36f17","order_by":0,"name":"Ning Ding","email":"","orcid":"","institution":"the First Affiliated Hospital of Nanjing Medical University","correspondingAuthor":false,"prefix":"","firstName":"Ning","middleName":"","lastName":"Ding","suffix":""},{"id":97443525,"identity":"59bad9ae-d479-42dd-8e59-36f27a8bc9a6","order_by":1,"name":"Mei Su","email":"","orcid":"","institution":"the First Affiliated Hospital of Nanjing Medical University","correspondingAuthor":false,"prefix":"","firstName":"Mei","middleName":"","lastName":"Su","suffix":""},{"id":97443526,"identity":"81f827c0-de61-4a5d-9523-4894b3a57393","order_by":2,"name":"Xu Qi","email":"","orcid":"","institution":"the First Affiliated Hospital of Nanjing Medical University","correspondingAuthor":false,"prefix":"","firstName":"Xu","middleName":"","lastName":"Qi","suffix":""},{"id":97443527,"identity":"bdbe73b5-7590-442e-a3e0-f72d3047b816","order_by":3,"name":"Buqing Ni","email":"","orcid":"","institution":"the First Affiliated Hospital of Nanjing Medical University","correspondingAuthor":false,"prefix":"","firstName":"Buqing","middleName":"","lastName":"Ni","suffix":""},{"id":97443528,"identity":"4a8a24ef-f217-45bc-b0d2-08c700c51e4d","order_by":4,"name":"Shijiang Zhang","email":"","orcid":"","institution":"the First Affiliated Hospital of Nanjing Medical University","correspondingAuthor":false,"prefix":"","firstName":"Shijiang","middleName":"","lastName":"Zhang","suffix":""},{"id":97443529,"identity":"40c62fd6-51cf-478b-a062-196131fab51d","order_by":5,"name":"Xilong Zhang","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAABDElEQVRIiWNgGAWjYDACCQgpAyIPfPxjI8fG3n6AKC08QILx4MyGNGM+njMJxGhhAGlhPszbcDhxnoSDAV4d8rObnz382mbBwy/dfuEw7w7m9DYJhgSGHxXbcGphnHPM3FjmjASP5JwzBQfnnmHLbZNuPMDYc+Y2Ti3MEglm0hIVEjwGN3ISDrxh48ltkzmQwMzYhlsLm0T6N2kJA6gWHiCXTSLBAK8WHokcM8kPYFvSDxzkbTNIIKhFQiKnTJoB5JcZOQwHZ5xJMGwDBvJBfH6Rn5G+TfJnW50cv0T64w8fKv7Ly7e3H3zwowK3FnAQ8EDciIiOA3jVAwHjDzDF/oCQwlEwCkbBKBihAAAHrVc8JEpGhQAAAABJRU5ErkJggg==","orcid":"","institution":"the First Affiliated Hospital of Nanjing Medical University","correspondingAuthor":true,"prefix":"","firstName":"Xilong","middleName":"","lastName":"Zhang","suffix":""}],"badges":[],"createdAt":"2022-02-24 08:14:15","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-1391530/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-1391530/v1","draftVersion":[],"editorialEvents":[],"editorialNote":"","failedWorkflow":false,"files":[{"id":20204790,"identity":"e4c43e61-b110-42aa-99bc-05f285041f43","added_by":"auto","created_at":"2022-04-11 16:54:34","extension":"jpg","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":703553,"visible":true,"origin":"","legend":"\u003cp\u003eFlowchart of patients enrollment.\u003c/p\u003e","description":"","filename":"Figure1.jpg","url":"https://assets-eu.researchsquare.com/files/rs-1391530/v1/ef9a90c069fe6f3e3019782e.jpg"},{"id":22165598,"identity":"4c004c36-b97b-4012-addd-59da8de499f8","added_by":"auto","created_at":"2022-06-02 07:44:28","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":462588,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-1391530/v1/cbce2d26-8937-44d9-a27c-2f7124cc6582.pdf"}],"financialInterests":"No competing interests reported.","formattedTitle":"Impact of 1-week preoperative auto-CPAP treatment on postoperative outcomes in patients undergoing heart valve replacement surgery: a prospective randomized controlled trial","fulltext":[{"header":"Introduction","content":"\u003cp\u003eObstructive sleep apnea (OSA) is one of the most common sleep disorders in adults, with reported prevalence rates between 16% and 84% \u003csup\u003e1,2\u003c/sup\u003e. OSA is associated with increased all-cause and cardiovascular mortality risks, as well as the incidence of hypertension \u003csup\u003e\u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e\u003c/sup\u003e, coronary heart disease, heart failure and postoperative cardiovascular events (sudden cardiac death, atrial fibrillation, congestive heart failure, and myocardial injury) \u003csup\u003e\u003cspan additionalcitationids=\"CR5\" citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e\u003c/sup\u003e. In our previous study we reported that OSA is common in patients undergoing cardiac valve replacement (CVR). Moreover, preoperative OSA is associated with an increased mechanical ventilation duration and a longer intensive care unit (ICU) stay, as well as a higher rate of postoperative pacemaker use \u003csup\u003e\u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e\u003c/sup\u003e.\u003c/p\u003e \u003cp\u003eContinuous positive airway pressure (CPAP) is the mainstay treatment for patients with OSA. A previous study showed that the postoperative complications are increased in patients with untreated OSA who undergo general and vascular surgery \u003csup\u003e\u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e\u003c/sup\u003e. Although it is well-established that perioperative CPAP significantly reduces the postoperative apnea-hypopnea index (AHI) and pulmonary complications, improves the oxygen saturation, and shortens the length of hospital stay following cardiac and non-cardiac surgery \u003csup\u003e\u003cspan additionalcitationids=\"CR10 CR11\" citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e12\u003c/span\u003e\u003c/sup\u003e; however, it is not completely clear whether perioperative CPAP improves the postoperative outcomes in patients undergoing CVR surgery.\u003c/p\u003e \u003cp\u003eThe objective of this study was to determine if perioperative CPAP treatment could inprove postoperatienve adverse events, including decreasing the lengths of stay (hospital, preoperative, postoperative, and ICU), cardiac complications (postoperative arrhythmias, pacemaker use, first dose of dopamine in the ICU, and first dose of dobutamine in the ICU), and respiratory complications (reintubation, pneumonia, and duration of mechanical ventilation).\u003c/p\u003e"},{"header":"Materials And Methods","content":"\u003cp\u003e \u003cb\u003ePatients and study design.\u003c/b\u003e Between January 2018 and December 2019, a total of 223 patients with rheumatic valvular heart disease (18\u0026ndash;75 years of age) undergoing CVR were screened for OSA using ApneaLink\u0026trade; Air (ResMed Corp., Australia) in the first 3 days of hospitalization. Patients with OSA who agreed to participate in our study underwent an overnight polysomnography (PSG) the next day. The patients with an AHI\u0026thinsp;\u0026ge;\u0026thinsp;5/h were randomly assigned to the CPAP (n\u0026thinsp;=\u0026thinsp;17) and non-CPAP treatment groups (n\u0026thinsp;=\u0026thinsp;17). Patients in the CPAP treatment group received CPAP\u0026thinsp;+\u0026thinsp;basic treatment for 7 d (15 patients completed the 7-d treatment). Patients in the non-CPAP treatment group received basic treatment for 7 d. All patients underwent CVR surgery 1 week after completing treatment. The patients were admitted to the ICU and received mechanical ventilation postoperatively. The postoperative PSG was performed 1\u0026ndash;3 d prior to hospital discharge.\u003c/p\u003e \u003cp\u003eThe inclusion criteria were as follows: (1) 18\u0026thinsp;\u0026minus;\u0026thinsp;75 years of age; (2) diagnosed with rheumatic valvular heart disease; (3) diagnosed with OSA (AHI\u0026thinsp;\u0026gt;\u0026thinsp;=\u0026thinsp;5/h). (4) received heart valve replacement surgery; and (5) signed informed consent. The exclusion criteria were as follows: (1) history of stroke or clinical signs of peripheral or central nervous system disorders; (2) previously known congenital heart disease, coronary heart disease, myocardial infarction, dilated cardiomyopathy, or hypertrophic cardiomyopathy; and (3) chronic obstructive pulmonary disease or a history of asthma. Figure\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003e shows the study design flow chart.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003eRandomized method: Random sequence numbers (1\u0026thinsp;\u0026minus;\u0026thinsp;34) were generated using Excel software by a statistician who did not otherwise take part in this study. According to the order of enrollment, the random sequence number was used one-by-one. Odd numbers were assigned to the CPAP treatment group and even numbers were assigned to the non-CPAP treatment group. The statistician and the data collector were blinded to interventions and the care providers were blinded to outcome parameters.\u003c/p\u003e \u003cp\u003ePreoperative basic treatment included oxygen and optimal medications. Oxygen therapy was administered when a patient had a pulse oxygen saturation (SpO\u003csub\u003e2\u003c/sub\u003e)\u0026thinsp;\u0026lt;\u0026thinsp;90%. The optimal medication therapy included digoxin, diuretics, nitrates, an angiotensin-converting enzyme inhibitor/ angiotensin receptor blocker, and a β-blocker.\u003c/p\u003e \u003cp\u003eThe diagnosis of rheumatic valvular heart disease was based on the 2012 criteria for the diagnosis of rheumatic fever and rheumatic heart disease, as follows \u003csup\u003e\u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e13\u003c/span\u003e\u003c/sup\u003e: a primary episode of rheumatic fever or current clinical rheumatic heart disease as featured and typical rheumatic valvular lesions were examined by Doppler echocardiography.\u003c/p\u003e \u003cp\u003e \u003cb\u003eBaseline clinical evaluation.\u003c/b\u003e The preoperative physical examinations and heart function evaluations were performed by the same physician. Patient height, weight, and body mass index (BMI [weight in kg/height in m\u003csup\u003e\u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e\u003c/sup\u003e]) were recorded. The New York Heart Association (NYHA) classification was determined. Atrial fibrillation was detected by 12-lead electrocardiography. Two-dimensional Doppler echocardiography was performed to assess left ventricular ejection fraction (LVEF). Valvular disease was assessed by echocardiography and confirmed by pathologic evaluation postoperatively. The 6-min walking test (6MWT) was performed within 3 d after hospital admission, as we previously reported \u003csup\u003e\u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e,\u003cspan citationid=\"CR14\" class=\"CitationRef\"\u003e14\u003c/span\u003e\u003c/sup\u003e.\u003c/p\u003e \u003cp\u003e \u003cb\u003ePolysomnography.\u003c/b\u003e The Epworth Sleepiness Scale (ESS) score was recorded before the sleep study to assess daytime sleepiness. The sleep study was an unattended overnight PSG (Alice 6 LDx System; Respironics, Inc., Netherlands) pre- and postoperatively. We used the 2012 standards of the American Academy of Sleep Medicine (AASM) \u003csup\u003e\u003cspan citationid=\"CR15\" class=\"CitationRef\"\u003e15\u003c/span\u003e\u003c/sup\u003e to score sleep apnea (SA) types and associated events, as described previously \u003csup\u003e\u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e\u003c/sup\u003e: obstructive apnea, \u0026gt; 90% decrease in airflow with continued paradoxical chest and abdominal excursion for \u0026ge;\u0026thinsp;10 s; central apnea, \u0026gt; 90% decrease in airflow as well as complete cessation of chest and abdominal excursion\u0026thinsp;\u0026ge;\u0026thinsp;10 s; and hypopnea-reduction of airflow, \u0026gt; 50% baseline lasting\u0026thinsp;\u0026ge;\u0026thinsp;10 s and associated with \u0026ge;\u0026thinsp;3% desaturation. The AHI was defined as the number of apneic and hypopneic events per h of sleep. An AHI of \u0026ge;\u0026thinsp;5/h was considered diagnostic for SA. Sleep apnea in which greater than 50% of events were obstructive, was defined as OSA.\u003c/p\u003e \u003cp\u003e \u003cb\u003eCPAP treatment.\u003c/b\u003e An auto-CPAP (S9 Auto Set; ResMed Corp., Australia) treatment regimen (auto-CPAP, 4\u0026ndash;16 cm H\u003csub\u003e2\u003c/sub\u003eO) was offered to the patients in the CPAP treatment group. Recordings with a mean CPAP use\u0026thinsp;\u0026gt;\u0026thinsp;4 h/night were accepted for each patient \u003csup\u003e\u003cspan citationid=\"CR16\" class=\"CitationRef\"\u003e16\u003c/span\u003e\u003c/sup\u003e. To prevent confounding, all patients used the same CPAP device, and underwent the same clinical evaluations, follow-up assessments, and education regarding OSA and proper CPAP use. All patients had formal mask fitting prior to initiating CPAP therapy.\u003c/p\u003e \u003cp\u003e\u003cb\u003eCardiac valve replacement.\u003c/b\u003e CVR was performed in accordance with the American College of Cardiology/American Heart Association guidelines and indications for valve replacement in patients with valvular heart disease \u003csup\u003e\u003cspan citationid=\"CR17\" class=\"CitationRef\"\u003e17\u003c/span\u003e\u003c/sup\u003e. The valve prosthesis type selection was at the discretion of the operating surgeon. All procedures were performed under cardiopulmonary bypass with mild systemic hypothermia (30\u0026deg;C\u0026ndash;34\u0026deg;C). Myocardial protection was achieved with cold blood cardioplegia.\u003c/p\u003e \u003cp\u003e \u003cb\u003ePostoperative treatment.\u003c/b\u003e Patients were admitted to the ICU as soon as possible following CVR surgery. All patients received standard care, including vital sign monitoring, oxygen therapy, mechanical ventilation, and administration of vasoactive agents. All tests or therapies were considered clinically indicated by the surgical team.\u003c/p\u003e \u003cp\u003e \u003cb\u003ePostoperative outcome assessment.\u003c/b\u003e Lengths of stay (hospital, preoperative, postoperative, and ICU), cardiac complications (postoperative arrhythmias, pacemaker use, first dose of dopamine in the ICU, and first dose of dobutamine in the ICU), and respiratory complications (reintubation, pneumonia, and duration of mechanical ventilation) were assessed and compared between the CPAP and non-CPAP treatment groups.\u003c/p\u003e \u003cp\u003e \u003cb\u003eStatistical analysis.\u003c/b\u003e The differences between the CPAP and non-CPAP treatment groups of continuous variables were non-normally distributed and tested using the two independent samples Mann-Whitney U test and presented as medians and interquartile ranges. The pre- and postoperative differences for each group were tested by the paired samples Mann-Whitney U test and presented as medians and interquartile ranges. Categorical variables were compared using the chi-square test with a normal approximation or Fisher\u0026rsquo;s exact test, as appropriate.\u003c/p\u003e \u003cp\u003eTwo-tailed \u003cem\u003eP\u003c/em\u003e values\u0026thinsp;\u0026lt;\u0026thinsp;0.05 were considered statistically significant. Statistical analyses were performed with SPSS 22.0 statistical software (IBM\u0026reg; SPSS, Inc., Chicago, IL, USA).\u003c/p\u003e\u003cp\u003e\u003cstrong\u003eEthics approval and consent to participate.\u003c/strong\u003e The studies were approved by the local institutional review board (Clinical Study Ethics Committee of the First Affiliated Hospital of Nanjing Medical University, No. 2017-SR-040) and registered in ClinicalTrials.gov (ID: NCT03398733, 12/01/2018). The procedures used in this study adhered to the tenets of the Declaration of Helsinki. All participants provided written informed consent when the patients underwent OSA screening.\u003c/p\u003e "},{"header":"Results","content":"\u003cp\u003e\u003cstrong\u003eBaseline participant characteristics.\u0026nbsp;\u003c/strong\u003eWe screened 232 patients with valvular heart disease, 34 of whom with OSA were enrolled and randomized into the CPAP and non-CPAP treatment groups. Fifteen patients in the CPAP treatment group and 17 patients in the non-CPAP treatment group completed the preoperative treatment and postoperative PSG testing (Figure 1). Table 1 shows a comparison of the baseline characteristics between the CPAP and non-CPAP treatment groups. There was no significant difference with respect to age, BMI, sex, atrial fibrillation, heart valve lesions, NYHA class, medication use, LVEF, 6MWT distance, and arterial blood gas results.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eComparisons of sleep data.\u0026nbsp;\u003c/strong\u003eThe total recording time, total sleep time, sleep efficiency, arousal index, sleep stage, AHI, AI, HI, mean SpO\u003csub\u003e2\u003c/sub\u003e, minimal SpO\u003csub\u003e2\u003c/sub\u003e, and\u0026nbsp;oxygen desaturation index\u0026nbsp;(ODI) were recorded or calculated (Table 2). There was no significant difference in the baseline sleep parameters between the\u0026nbsp;CPAP and non-CPAP treatment groups preoperatively. The AHI, AI, and ODI were significantly decreased, and the mean and minimal SpO\u003csub\u003e2\u003c/sub\u003e were significantly increased during CPAP treatment. The AHI, AI, and ODI were significantly decreased postoperatively compared with preoperatively (baseline)\u0026nbsp;in the CPAP and non-CPAP treatment groups.\u0026nbsp;There was no significant difference in the sleep parameters between the\u0026nbsp;CPAP and non-CPAP treatment groups postoperatively.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003ePostoperative complications.\u003c/strong\u003e Table 3 showesthe lengths of postoperative and ICU stays, and the duration of mechanical ventilation were significantly reduced in the CPAP treatment group compared to the non-CPAP treatment group. There was no significant difference in the length of hospital stay, cardiac complications (postoperative arrhythmias, pacemaker use, first dose of dopamine in the ICU, and first dose of dobutamine in the ICU), and respiratory complications (reintubation and pneumonia).\u003c/p\u003e"},{"header":"Discussion","content":"\u003cp\u003eThe present study was a novel, randomized controlled trial to determine the effectiveness of preoperative CPAP in patients with OSA undergoing CVR surgery. OSA is a well-documented risk factor associated with perioperative adverse outcomes.\u0026nbsp;Due to recurrent sleep apnea, intermittent hypoxia, and arousal, postoperative adverse events, such as arrhythmias, myocardial injury, and pulmonary infection, may occur.\u0026nbsp;In the Postoperative Vascular Complications in Unrecognized OSA (POSA) study, Chan and colleagues \u003csup\u003e6\u003c/sup\u003e observed 1,218 patients and concluded that severe OSA was significantly associated with a higher rate of postoperative cardiovascular events. Our previous study showed that patients with OSA were at increased perioperative risk for CVR surgery and associated with overall postoperative recovery, including respiratory insufficiency and a higher rate of postoperative pacemaker use\u0026nbsp;\u003csup\u003e7\u003c/sup\u003e.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eCPAP treatment during sleep for OSA patients has been shown to significantly reduce AHI and sleepiness, and improve oxygen deficiency\u0026nbsp;\u003csup\u003e10\u003c/sup\u003e. Although treatment of OSA appears to reduce postoperative pulmonary complications, pneumonia, and reintubation rates in patients undergoing major abdominal\u0026nbsp;\u003csup\u003e9\u003c/sup\u003e or heart surgery\u0026nbsp;\u003csup\u003e18,19\u003c/sup\u003e, no definitive data have shown whether preoperative CPAP reduces postoperative complications\u0026nbsp;in patients undergoing CVR surgery.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eRennotte et al.\u0026nbsp;\u003csup\u003e18\u003c/sup\u003e reported the effectiveness of CPAP in a case series involving 16 OSA patients. He showed that two OSA patients without preoperative CPAP treatment experienced postoperative adverse events and one patient died, whereas 14 patients with preoperative CPAP treatment had an uneventful postoperative course. Liao et al.\u0026nbsp;\u003csup\u003e10\u003c/sup\u003e developed a randomized controlled trial and confirmed that perioperative auto-CPAP treatment significantly reduced postoperative AHI and improved oxygen saturation in OSA patients.\u0026nbsp;In the present study, the patients in the CPAP group received preoperative auto-CPAP treatment for 1 week. The AHI was decreased and the minimal SpO\u003csub\u003e2\u003c/sub\u003e was increased significantly during CPAP treatment compared with the preoperative values (25 vs. 3 and 74% vs. 88%; both P values \u0026lt; 0.05), thus confirming CPAP treatment was effective in reducing sleep apnea and alleviating nocturnal hypoxemia.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eA number of studies have shown that postoperative CPAP use significantly reduced the AHI, improves oxygen saturation, and the incidence of postoperative cardiac and pulmonary complications\u0026nbsp;\u003csup\u003e10-12,16,18-23\u003c/sup\u003e. Due to edema in the upper airway, possible fluid shifts, sedation, and changes in sleep position, postoperative patients, especially patients with OSA, are more likely to have airway obstruction. Theoretically, postoperative CPAP use mitigates these issues as needed. Considering the possible lower adherence to CPAP following CVR surgery, we did not evaluate CPAP postoperatively in both the CPAP and control groups. Even though the postoperative AHI in both groups was slightly reduced (25 vs. 19 and 23 vs. 18; both P values \u0026lt; 0.05), the reduced AHI may be associated with surgery rather than CPAP treatment because central sleep apnea\u0026nbsp;can be eliminated after CVR\u0026nbsp;\u003csup\u003e14\u003c/sup\u003e.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eIn the present study patients with preoperative auto-CPAP treatment had a shorter duration of postoperative\u0026nbsp;mechanical ventilation, which may further lead to a reduction in ICU and postoperative hospital stays, thus suggesting that reducing the nocturnal hypoxemia and oxygen debt in OSA patients with\u0026nbsp;preoperative\u0026nbsp;CPAP therapy favored a faster postoperative recovery after CVR surgery.\u0026nbsp;A review reported that CPAP treatment reduced the rate of reintubation and admission into the ICU for invasive ventilation and supportive care\u0026nbsp;\u003csup\u003e24\u003c/sup\u003e. A matched cohort study showed that OSA patients who received CPAP therapy had a reduction in postoperative cardiovascular complications\u0026nbsp;\u003csup\u003e25\u003c/sup\u003e. Kindgen-Milles\u0026nbsp;\u003csup\u003e26\u003c/sup\u003e found that postoperative use of nasal CPAP significantly reduced pulmonary morbidity and the length of hospital stay following surgical repair of thoracoabdominal aortic aneurysms. Our results confirmed these findings in our patients undergoing CVR.\u0026nbsp;CPAP improved upper airway obstruction and increased lung volume, thereby significantly reducing apnea and hypopnea, and the associated hypoxemic and hypercapnic events\u0026nbsp;\u003csup\u003e11\u003c/sup\u003e. In addition, the patients treated with CPAP preoperatively may be more familiar and compliant with postoperative mechanical ventilation, which in turn may lead to mechanical ventilation of short duration.\u0026nbsp;Therefore, perioperative CPAP use may be beneficial in patients with OSA who undergo CVR surgery.\u003c/p\u003e\n\u003cp\u003eThe preoperative CPAP treatment did not reduce the incidence of postoperative arrhythmias, pacemaker use, reintubation, and pneumonia in the current study. Zarbock\u0026nbsp;\u003csup\u003e19\u003c/sup\u003e reported that nasal CPAP following cardiac surgery improved arterial oxygenation, reduced the incidence of pulmonary complications, including the pneumonia and reintubation rates, and reduced the readmission rate to the ICU; however, other studies have reported contradictory findings. Altmay\u0026nbsp;\u003csup\u003e27\u003c/sup\u003e observed patients with normal preoperative pulmonary function and CPAP use did not improve lung function after cardiac surgery. Furthermore, short-term CPAP treatment cannot reduce postoperative cardiac arrhythmias\u0026nbsp;\u003csup\u003e28,29\u003c/sup\u003e. There are many factors that induce\u0026nbsp;postoperative arrhythmias, pacemaker use, reintubation, and pneumonia, such as poor cardiac function, hypoxia, and malnutrition. CPAP treatment did not improve all of the aforementioned risk factors. In addition, in our study the small sample size and short time of CPAP treatment were reasons why our data\u0026nbsp;did not reach statistical significance.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eCPAP adherence in postoperative patients is low. Liao et al.\u0026nbsp;\u003csup\u003e11\u003c/sup\u003e found that the perioperative adherence rate of CPAP was only 45% and another study\u0026nbsp;\u003csup\u003e30\u003c/sup\u003e found only 33% of the patients had \u0026gt; 4 h CPAP treatment; the median adherence was 2.5 h per night. The author speculated that postoperative nausea and vomiting may be associated with reduced CPAP adherence; however, another study did not identify a relationship between the use of CPAP and the increased risk of postoperative nausea and vomiting\u0026nbsp;\u003csup\u003e31\u003c/sup\u003e.\u0026nbsp;With better control of postoperative pain and nausea/vomiting, adherence with CPAP among OSA patients may improve\u0026nbsp;\u003csup\u003e10\u003c/sup\u003e. Our patients had a good adherence with 88% completing \u0026gt; 4 h of CPAP treatment per night. This may be because our patients received short (1 week), preoperative but not postoperative, and in-hospital but not at home CPAP treatment.\u003c/p\u003e"},{"header":"Limitations","content":"\u003cp\u003eThere were limitations to our study. First, this study had a short-term clinical observation period, with a 1-week preoperative treatment and 12\u0026ndash;15 d postoperative in-hospital outcomes. Although all patients had scheduled follow-up evaluations, we anticipate collecting long-time outcomes in future. Second, even though this was a prospective controlled trial, we did not find significant differences in postoperative arrhythmias, pacemaker use, reintubation, and pneumonia, which may be due to the lack of complications in our study group as a result of the small sample size. Further multicenter and large sample studies are needed. Third, we only observed the effect of preoperative CPAP on postoperative outcomes. Postoperative CPAP use may have a more important role in reduction of the incidence of perioperative cardiac and pulmonary complications. Corollary studies are needed to answer the following important questions: What is the optimal duration of CPAP therapy in OSA patients undergoing CVR surgery? Is CPAP therapy effective preoperatively, postoperatively, or both? \u003c/p\u003e "},{"header":"Conclusion","content":"\u003cp\u003ePreoperative use of auto-CPAP for OSA significantly decreased the duration of mechanical ventilation, and postoperative ICU and hospital stays but failed to show any association with postoperative arrhythmias, pacemaker use, reintubation, and pneumonia.\u003c/p\u003e "},{"header":"Declarations","content":"\u003cp\u003e\u003cstrong\u003eAvailability of data and materials\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe datasets generated and/or analysed during the current study are not publicly available due to China\u0026rsquo;s personal data protection laws but are available from the corresponding author on reasonable request.\u003c/p\u003e\u003cp\u003e\u003cstrong\u003eAcknowledgments\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eNone.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eContributions\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eN.D, S.Z and X.Z designed the study. N.D, M.S, X.Q, B.N contributed data. N.D and X.Z performed the statistical analyses. All authors contributed to manuscript writing and revising. All authors read and approved the final manuscript.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eFunding:\u0026nbsp;\u003c/strong\u003eThis work was supported\u0026ensp;by\u0026ensp;the\u0026ensp;National\u0026ensp;Natural\u0026ensp;Science\u0026ensp;Foundation\u0026ensp;of\u0026ensp;China\u0026ensp;(Grant\u0026ensp;No. 82070093) and\u0026nbsp;511 Take-off Plan (Grant\u0026ensp;No. JSPH-511C-2018-10). The sponsor had no role in the design or conduct of this study.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eCompeting interests\u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe authors declare no competing interests.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eTrial registration number and date of registration\u003c/strong\u003e NCT03398733, 12/01/2018.\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\u003cli\u003e\u003cspan\u003eHeinzer, R. \u003cem\u003eet al.\u003c/em\u003e Prevalence of sleep-disordered breathing in the general population: the HypnoLaus study. 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C. \u003cem\u003eet al.\u003c/em\u003e A matched cohort study of postoperative outcomes in obstructive sleep apnea: could preoperative diagnosis and treatment prevent complications? \u003cem\u003eAnesthesiology\u003c/em\u003e \u003cb\u003e121\u003c/b\u003e, 707\u0026ndash;718, doi:\u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.1097/ALN.0000000000000407\u003c/span\u003e\u003cspan address=\"10.1097/ALN.0000000000000407\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e (2014).\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eKindgen-Milles, D. \u003cem\u003eet al.\u003c/em\u003e Nasal-continuous positive airway pressure reduces pulmonary morbidity and length of hospital stay following thoracoabdominal aortic surgery. Chest \u003cb\u003e128\u003c/b\u003e, 821\u0026ndash;828, doi:\u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.1378/chest.128.2.821\u003c/span\u003e\u003cspan address=\"10.1378/chest.128.2.821\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e (2005).\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eAltmay, E. \u003cem\u003eet al.\u003c/em\u003e Continuous positive airway pressure does not improve lung function after cardiac surgery. Can J Anaesth \u003cb\u003e53\u003c/b\u003e, 919\u0026ndash;925, doi:\u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.1007/BF03022835\u003c/span\u003e\u003cspan address=\"10.1007/BF03022835\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e (2006).\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eCampos, J. \u003cem\u003eet al.\u003c/em\u003e Acute response to 7-day therapy with CPAP in patients with moderate to severe obstructive sleep apnea and cardiac arrhytmia. Sleep Sci \u003cb\u003e11\u003c/b\u003e, 49\u0026ndash;53, doi:\u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.5935/1984-0063.20180011\u003c/span\u003e\u003cspan address=\"10.5935/1984-0063.20180011\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e (2018).\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eCaples, S. M., Mansukhani, M. P., Friedman, P. A. \u0026amp; Somers, V. K. The impact of continuous positive airway pressure treatment on the recurrence of atrial fibrillation post cardioversion: A randomized controlled trial. Int J Cardiol \u003cb\u003e278\u003c/b\u003e, 133\u0026ndash;136, doi:\u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.1016/j.ijcard.2018.11.100\u003c/span\u003e\u003cspan address=\"10.1016/j.ijcard.2018.11.100\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e (2019).\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eGuralnick, A. S., Pant, M., Minhaj, M., Sweitzer, B. J. \u0026amp; Mokhlesi, B. CPAP adherence in patients with newly diagnosed obstructive sleep apnea prior to elective surgery. J Clin Sleep Med \u003cb\u003e8\u003c/b\u003e, 501\u0026ndash;506, doi:\u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.5664/jcsm.2140\u003c/span\u003e\u003cspan address=\"10.5664/jcsm.2140\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e (2012).\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eMeng, L. Postoperative nausea and vomiting with application of postoperative continuous positive airway pressure after laparoscopic gastric bypass. Obes Surg \u003cb\u003e20\u003c/b\u003e, 876\u0026ndash;880, doi:\u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.1007/s11695-008-9741-2\u003c/span\u003e\u003cspan address=\"10.1007/s11695-008-9741-2\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e (2010).\u003c/span\u003e\u003c/li\u003e\u003c/ol\u003e"},{"header":"Tables","content":"\u003cp\u003e\u003cstrong\u003eTable 1.\u003c/strong\u003e Comparisons of patients\u0026rsquo; characteristics. Data are presented as median (interquartile range) or n (%). BMI body mass index, NYHA New York Heart Association, ACEI angiotensin-converting enzyme inhibitors, ARB angiotensin receptor blocker, LVEF left ventricular ejection fraction, 6MWT six-minute walking test.\u0026nbsp;\u003c/p\u003e\n\u003ctable border=\"1\" cellpadding=\"0\" cellspacing=\"0\" width=\"0\"\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd width=\"35.810810810810814%\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"25.135135135135137%\"\u003e\n \u003cp\u003eCPAP treatment group (n=15)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"28.783783783783782%\"\u003e\n \u003cp\u003eNon-CPAP treatment group (n=17)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"10.27027027027027%\"\u003e\n \u003cp\u003ep-value\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" width=\"35.810810810810814%\"\u003e\n \u003cp\u003eAge(yr)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"25.135135135135137%\"\u003e\n \u003cp\u003e56 (45 - 59)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"28.783783783783782%\"\u003e\n \u003cp\u003e56 (49 \u0026ndash; 61)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"10.27027027027027%\"\u003e\n \u003cp\u003e0.526\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" width=\"35.810810810810814%\"\u003e\n \u003cp\u003eBMI (kg/m\u003csup\u003e2\u003c/sup\u003e)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"25.135135135135137%\"\u003e\n \u003cp\u003e28.5 (27.4 \u0026ndash; 30.0)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"28.783783783783782%\"\u003e\n \u003cp\u003e26.8 (25.2 \u0026ndash; 29.7)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"10.27027027027027%\"\u003e\n \u003cp\u003e0.261\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" width=\"35.810810810810814%\"\u003e\n \u003cp\u003eGender\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"25.135135135135137%\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"28.783783783783782%\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"10.27027027027027%\"\u003e\n \u003cp\u003e0.946\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" width=\"35.810810810810814%\"\u003e\n \u003cp\u003e\u0026nbsp; Male, n (%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"25.135135135135137%\"\u003e\n \u003cp\u003e9 (60)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"28.783783783783782%\"\u003e\n \u003cp\u003e10 (58.8)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"10.27027027027027%\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" width=\"35.810810810810814%\"\u003e\n \u003cp\u003e\u0026nbsp; Female, n (%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"25.135135135135137%\"\u003e\n \u003cp\u003e6 (40)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"28.783783783783782%\"\u003e\n \u003cp\u003e7 (41.2)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"10.27027027027027%\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" width=\"35.810810810810814%\"\u003e\n \u003cp\u003eHeart valve lesions\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"25.135135135135137%\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"28.783783783783782%\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"10.27027027027027%\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" width=\"35.810810810810814%\"\u003e\n \u003cp\u003eMitral valve lesions, n (%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"25.135135135135137%\"\u003e\n \u003cp\u003e13 (86.7)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"28.783783783783782%\"\u003e\n \u003cp\u003e15 (88.2)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"10.27027027027027%\"\u003e\n \u003cp\u003e1.000\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" width=\"35.810810810810814%\"\u003e\n \u003cp\u003eAortic valve lesions, n (%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"25.135135135135137%\"\u003e\n \u003cp\u003e9 (60)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"28.783783783783782%\"\u003e\n \u003cp\u003e10 (58.8)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"10.27027027027027%\"\u003e\n \u003cp\u003e0.946\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" width=\"35.810810810810814%\"\u003e\n \u003cp\u003eTricuspid valve lesions, n (%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"25.135135135135137%\"\u003e\n \u003cp\u003e13 (86.7)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"28.783783783783782%\"\u003e\n \u003cp\u003e8 (47.1)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"10.27027027027027%\"\u003e\n \u003cp\u003e0.015\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" width=\"35.810810810810814%\"\u003e\n \u003cp\u003eNYHA class\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"25.135135135135137%\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"28.783783783783782%\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"10.27027027027027%\"\u003e\n \u003cp\u003e0.513\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" width=\"35.810810810810814%\"\u003e\n \u003cp\u003eⅡ, n\u0026nbsp;(%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"25.135135135135137%\"\u003e\n \u003cp\u003e1 (6.7)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"28.783783783783782%\"\u003e\n \u003cp\u003e3 (17.6)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"10.27027027027027%\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" width=\"35.810810810810814%\"\u003e\n \u003cp\u003eⅢ, n\u0026nbsp;(%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"25.135135135135137%\"\u003e\n \u003cp\u003e10 (66.7)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"28.783783783783782%\"\u003e\n \u003cp\u003e10 (58.8)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"10.27027027027027%\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" width=\"35.810810810810814%\"\u003e\n \u003cp\u003eⅣ, n\u0026nbsp;(%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"25.135135135135137%\"\u003e\n \u003cp\u003e4 (26.7)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"28.783783783783782%\"\u003e\n \u003cp\u003e4 (23.5)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"10.27027027027027%\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" width=\"35.810810810810814%\"\u003e\n \u003cp\u003eAtrial fibrillation, n (%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"25.135135135135137%\"\u003e\n \u003cp\u003e12 (80)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"28.783783783783782%\"\u003e\n \u003cp\u003e12 (70.6)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"10.27027027027027%\"\u003e\n \u003cp\u003e0.691\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" width=\"35.810810810810814%\"\u003e\n \u003cp\u003eHypertension\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"25.135135135135137%\"\u003e\n \u003cp\u003e4\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"28.783783783783782%\"\u003e\n \u003cp\u003e6\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"10.27027027027027%\"\u003e\n \u003cp\u003e0.712\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" width=\"35.810810810810814%\"\u003e\n \u003cp\u003eMedication use\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"25.135135135135137%\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"28.783783783783782%\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"10.27027027027027%\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" width=\"35.810810810810814%\"\u003e\n \u003cp\u003eDigoxin\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"25.135135135135137%\"\u003e\n \u003cp\u003e12 (80)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"28.783783783783782%\"\u003e\n \u003cp\u003e13 (76.5)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"10.27027027027027%\"\u003e\n \u003cp\u003e1.000\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" width=\"35.810810810810814%\"\u003e\n \u003cp\u003eDiuretics\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"25.135135135135137%\"\u003e\n \u003cp\u003e13 (86.7)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"28.783783783783782%\"\u003e\n \u003cp\u003e13 (76.5)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"10.27027027027027%\"\u003e\n \u003cp\u003e0.659\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" width=\"35.810810810810814%\"\u003e\n \u003cp\u003eACEI/ARB\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"25.135135135135137%\"\u003e\n \u003cp\u003e10 (66.7)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"28.783783783783782%\"\u003e\n \u003cp\u003e9 (52.9)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"10.27027027027027%\"\u003e\n \u003cp\u003e0.668\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" width=\"35.810810810810814%\"\u003e\n \u003cp\u003e\u0026beta;-blockers\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"25.135135135135137%\"\u003e\n \u003cp\u003e8 (53.3)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"28.783783783783782%\"\u003e\n \u003cp\u003e13 (76.5)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"10.27027027027027%\"\u003e\n \u003cp\u003e0.266\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" width=\"35.810810810810814%\"\u003e\n \u003cp\u003eLVEF (%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"25.135135135135137%\"\u003e\n \u003cp\u003e63.4 (58 \u0026ndash; 65.4)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"28.783783783783782%\"\u003e\n \u003cp\u003e62.5 (58.7 \u0026ndash; 66.2)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"10.27027027027027%\"\u003e\n \u003cp\u003e0.737\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" width=\"35.810810810810814%\"\u003e\n \u003cp\u003e6MWT distance (m)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"25.135135135135137%\"\u003e\n \u003cp\u003e426 (369 \u0026ndash; 447)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"28.783783783783782%\"\u003e\n \u003cp\u003e414 (364 \u0026ndash; 460)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"10.27027027027027%\"\u003e\n \u003cp\u003e0.823\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" width=\"35.810810810810814%\"\u003e\n \u003cp\u003eArterial blood gas\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"25.135135135135137%\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"28.783783783783782%\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"10.27027027027027%\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" width=\"35.810810810810814%\"\u003e\n \u003cp\u003epH\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"25.135135135135137%\"\u003e\n \u003cp\u003e7.42 (7.36 \u0026ndash; 7.44)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"28.783783783783782%\"\u003e\n \u003cp\u003e7.43 (7.38 \u0026ndash; 7.46)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"10.27027027027027%\"\u003e\n \u003cp\u003e0.502\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" width=\"35.810810810810814%\"\u003e\n \u003cp\u003ePaO\u003csub\u003e2\u003c/sub\u003e, mmHg\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"25.135135135135137%\"\u003e\n \u003cp\u003e80 (75 \u0026ndash; 86)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"28.783783783783782%\"\u003e\n \u003cp\u003e81 (72 \u0026ndash; 88)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"10.27027027027027%\"\u003e\n \u003cp\u003e0.823\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" width=\"35.810810810810814%\"\u003e\n \u003cp\u003ePaCO\u003csub\u003e2\u003c/sub\u003e, mmHg\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"25.135135135135137%\"\u003e\n \u003cp\u003e47 (42 \u0026ndash; 48)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"28.783783783783782%\"\u003e\n \u003cp\u003e44 (41 \u0026ndash; 48)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"10.27027027027027%\"\u003e\n \u003cp\u003e0.411\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n\u003c/table\u003e\n\u003cp\u003e\u003cstrong\u003eTable 2.\u003c/strong\u003e Comparisons of polysomnography data. Data are presented as median (interquartile range) or n (%).\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eREM rapid eye movement,\u0026nbsp;AHI\u0026nbsp;apnea/hypopnea index, AI apnea index, HI hypopnea index,\u0026nbsp;SpO\u003csub\u003e2\u003c/sub\u003e pulse oxygen saturation, ODI oxygen desaturation index.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e*\u003cem\u003e\u0026nbsp;\u003c/em\u003ep \u0026lt;0.05, between baseline and CPAP treatment; \u0026dagger; p-values for within group comparisons, between baseline and postoperative; \u0026Dagger; p-value for postoperative comparisons between groups.\u003c/p\u003e\n\u003ctable border=\"1\" cellpadding=\"0\" cellspacing=\"0\" width=\"0\"\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd rowspan=\"2\" width=\"16.561181434599156%\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd colspan=\"4\" width=\"43.565400843881854%\"\u003e\n \u003cp\u003eCPAP treatment group (n=15)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd colspan=\"3\" width=\"31.645569620253166%\"\u003e\n \u003cp\u003eNon-CPAP treatment group (n=17)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd rowspan=\"2\" valign=\"top\" width=\"8.227848101265822%\"\u003e\n \u003cp\u003ep-value\u0026Dagger;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"15.826330532212886%\"\u003e\n \u003cp\u003eBaseline (Preoperative)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"15.686274509803921%\"\u003e\n \u003cp\u003eCPAP treatment\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"14.985994397759104%\"\u003e\n \u003cp\u003ePostoperative\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"11.344537815126051%\"\u003e\n \u003cp\u003ep-value\u0026dagger;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"15.826330532212886%\"\u003e\n \u003cp\u003eBaseline (Preoperative)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"15.826330532212886%\"\u003e\n \u003cp\u003ePostoperative\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"10.504201680672269%\"\u003e\n \u003cp\u003ep-value\u0026dagger;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" width=\"16.54373024236038%\"\u003e\n \u003cp\u003eTotal recording time (h)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"11.9072708113804%\"\u003e\n \u003cp\u003e546 (518 - 574)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"11.801896733403582%\"\u003e\n \u003cp\u003eNA\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"11.275026343519494%\"\u003e\n \u003cp\u003e553 (538 - 573)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"8.535300316122234%\"\u003e\n \u003cp\u003e0.513\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"11.9072708113804%\"\u003e\n \u003cp\u003e537 (520 - 560)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"11.9072708113804%\"\u003e\n \u003cp\u003e551 (522 - 576)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"7.903055848261328%\"\u003e\n \u003cp\u003e0.236\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"8.219178082191782%\"\u003e\n \u003cp\u003e0.655\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" width=\"16.54373024236038%\"\u003e\n \u003cp\u003eTotal sleep time (h)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"11.9072708113804%\"\u003e\n \u003cp\u003e388 (366 - 423)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"11.801896733403582%\"\u003e\n \u003cp\u003eNA\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"11.275026343519494%\"\u003e\n \u003cp\u003e383 (369 - 403)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"8.535300316122234%\"\u003e\n \u003cp\u003e0.074\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"11.9072708113804%\"\u003e\n \u003cp\u003e405 (385 -414)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"11.9072708113804%\"\u003e\n \u003cp\u003e387 (364 - 409)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"7.903055848261328%\"\u003e\n \u003cp\u003e0.035\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"8.219178082191782%\"\u003e\n \u003cp\u003e0.455\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" width=\"16.54373024236038%\"\u003e\n \u003cp\u003eSleep efficiency (%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"11.9072708113804%\"\u003e\n \u003cp\u003e73 (68 - 76)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"11.801896733403582%\"\u003e\n \u003cp\u003eNA\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"11.275026343519494%\"\u003e\n \u003cp\u003e68 (67 - 75)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"8.535300316122234%\"\u003e\n \u003cp\u003e0.088\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"11.9072708113804%\"\u003e\n \u003cp\u003e74 (70 - 78)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"11.9072708113804%\"\u003e\n \u003cp\u003e71 (67 - 75)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"7.903055848261328%\"\u003e\n \u003cp\u003e0.076\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"8.219178082191782%\"\u003e\n \u003cp\u003e0.350\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" width=\"16.54373024236038%\"\u003e\n \u003cp\u003eArousal index, h\u003csup\u003e-1\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"11.9072708113804%\"\u003e\n \u003cp\u003e21 (18 - 29)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"11.801896733403582%\"\u003e\n \u003cp\u003eNA\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"11.275026343519494%\"\u003e\n \u003cp\u003e17 (13 - 26)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"8.535300316122234%\"\u003e\n \u003cp\u003e0.005\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"11.9072708113804%\"\u003e\n \u003cp\u003e19 (15 - 25)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"11.9072708113804%\"\u003e\n \u003cp\u003e15 (11 - 22)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"7.903055848261328%\"\u003e\n \u003cp\u003e0.003\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"8.219178082191782%\"\u003e\n \u003cp\u003e0.655\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" width=\"16.54373024236038%\"\u003e\n \u003cp\u003eSleep stage\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"11.9072708113804%\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"11.801896733403582%\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"11.275026343519494%\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"8.535300316122234%\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"11.9072708113804%\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"11.9072708113804%\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"7.903055848261328%\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"8.219178082191782%\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" width=\"16.54373024236038%\"\u003e\n \u003cp\u003e\u0026nbsp; N 1 sleep (%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"11.9072708113804%\"\u003e\n \u003cp\u003e14 (12 - 19)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"11.801896733403582%\"\u003e\n \u003cp\u003eNA\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"11.275026343519494%\"\u003e\n \u003cp\u003e14 (12 - 16)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"8.535300316122234%\"\u003e\n \u003cp\u003e0.105\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"11.9072708113804%\"\u003e\n \u003cp\u003e14 (12 - 17)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"11.9072708113804%\"\u003e\n \u003cp\u003e15 (11 - 16)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"7.903055848261328%\"\u003e\n \u003cp\u003e0.527\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"8.219178082191782%\"\u003e\n \u003cp\u003e0.551\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" width=\"16.54373024236038%\"\u003e\n \u003cp\u003e\u0026nbsp; N 2 sleep (%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"11.9072708113804%\"\u003e\n \u003cp\u003e60 (56 - 63)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"11.801896733403582%\"\u003e\n \u003cp\u003eNA\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"11.275026343519494%\"\u003e\n \u003cp\u003e61 (58 - 65)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"8.535300316122234%\"\u003e\n \u003cp\u003e0.022\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"11.9072708113804%\"\u003e\n \u003cp\u003e58 (56 - 61)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"11.9072708113804%\"\u003e\n \u003cp\u003e63 (59 - 67)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"7.903055848261328%\"\u003e\n \u003cp\u003e0.004\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"8.219178082191782%\"\u003e\n \u003cp\u003e0.295\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" width=\"16.54373024236038%\"\u003e\n \u003cp\u003e\u0026nbsp; N 3 sleep (%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"11.9072708113804%\"\u003e\n \u003cp\u003e8 (6 - 10)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"11.801896733403582%\"\u003e\n \u003cp\u003eNA\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"11.275026343519494%\"\u003e\n \u003cp\u003e9 (8 - 12)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"8.535300316122234%\"\u003e\n \u003cp\u003e0.030\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"11.9072708113804%\"\u003e\n \u003cp\u003e10 (8 - 12)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"11.9072708113804%\"\u003e\n \u003cp\u003e7 (5 - 10)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"7.903055848261328%\"\u003e\n \u003cp\u003e0.055\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"8.219178082191782%\"\u003e\n \u003cp\u003e0.216\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" width=\"16.54373024236038%\"\u003e\n \u003cp\u003e\u0026nbsp; REM sleep (%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"11.9072708113804%\"\u003e\n \u003cp\u003e18 (14 - 21)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"11.801896733403582%\"\u003e\n \u003cp\u003eNA\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"11.275026343519494%\"\u003e\n \u003cp\u003e17 (12 - 18)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"8.535300316122234%\"\u003e\n \u003cp\u003e0.237\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"11.9072708113804%\"\u003e\n \u003cp\u003e16 (13 - 20)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"11.9072708113804%\"\u003e\n \u003cp\u003e13 (11 - 17)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"7.903055848261328%\"\u003e\n \u003cp\u003e0.046\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"8.219178082191782%\"\u003e\n \u003cp\u003e0.370\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" width=\"16.54373024236038%\"\u003e\n \u003cp\u003eAHI, h\u003csup\u003e-1\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"11.9072708113804%\"\u003e\n \u003cp\u003e25 (19 - 33)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"11.801896733403582%\"\u003e\n \u003cp\u003e3 (1 - 5) *\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"11.275026343519494%\"\u003e\n \u003cp\u003e19 (14 - 28)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"8.535300316122234%\"\u003e\n \u003cp\u003e0017\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"11.9072708113804%\"\u003e\n \u003cp\u003e23 (17 - 28)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"11.9072708113804%\"\u003e\n \u003cp\u003e18 (13 - 27)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"7.903055848261328%\"\u003e\n \u003cp\u003e0.026\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"8.219178082191782%\"\u003e\n \u003cp\u003e0.766\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" width=\"16.54373024236038%\"\u003e\n \u003cp\u003eAI, h\u003csup\u003e-1\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"11.9072708113804%\"\u003e\n \u003cp\u003e22 (13 - 25)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"11.801896733403582%\"\u003e\n \u003cp\u003e0 (0 - 1) *\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"11.275026343519494%\"\u003e\n \u003cp\u003e13 (8 - 18)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"8.535300316122234%\"\u003e\n \u003cp\u003e0.004\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"11.9072708113804%\"\u003e\n \u003cp\u003e19 (14 - 22)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"11.9072708113804%\"\u003e\n \u003cp\u003e14 (10 - 20)\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"7.903055848261328%\"\u003e\n \u003cp\u003e0.007\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"8.219178082191782%\"\u003e\n \u003cp\u003e0.551\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" width=\"16.54373024236038%\"\u003e\n \u003cp\u003eHI, h\u003csup\u003e-1\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"11.9072708113804%\"\u003e\n \u003cp\u003e4 (3 - 11)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"11.801896733403582%\"\u003e\n \u003cp\u003e3 (1 - 3) *\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"11.275026343519494%\"\u003e\n \u003cp\u003e6 (5 - 10)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"8.535300316122234%\"\u003e\n \u003cp\u003e0.101\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"11.9072708113804%\"\u003e\n \u003cp\u003e4 (3 - 6)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"11.9072708113804%\"\u003e\n \u003cp\u003e5 (3 - 7)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"7.903055848261328%\"\u003e\n \u003cp\u003e0.408\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"8.219178082191782%\"\u003e\n \u003cp\u003e0.064\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" width=\"16.54373024236038%\"\u003e\n \u003cp\u003eMean SpO\u003csub\u003e2\u003c/sub\u003e (%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"11.9072708113804%\"\u003e\n \u003cp\u003e92 (89 - 92)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"11.801896733403582%\"\u003e\n \u003cp\u003e95 (95 - 97) *\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"11.275026343519494%\"\u003e\n \u003cp\u003e91 (90 - 92)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"8.535300316122234%\"\u003e\n \u003cp\u003e0.406\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"11.9072708113804%\"\u003e\n \u003cp\u003e92 (90 - 94)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"11.9072708113804%\"\u003e\n \u003cp\u003e92 (91 - 94)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"7.903055848261328%\"\u003e\n \u003cp\u003e0.547\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"8.219178082191782%\"\u003e\n \u003cp\u003e0.189\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" width=\"16.54373024236038%\"\u003e\n \u003cp\u003eMinimal SpO\u003csub\u003e2\u003c/sub\u003e (%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"11.9072708113804%\"\u003e\n \u003cp\u003e74 (70 - 79)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"11.801896733403582%\"\u003e\n \u003cp\u003e88 (84 \u0026ndash; 90) *\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"11.275026343519494%\"\u003e\n \u003cp\u003e77 (73 - 82)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"8.535300316122234%\"\u003e\n \u003cp\u003e0.104\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"11.9072708113804%\"\u003e\n \u003cp\u003e72 (67 - 77)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"11.9072708113804%\"\u003e\n \u003cp\u003e74 (70 - 80)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"7.903055848261328%\"\u003e\n \u003cp\u003e0.016\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"8.219178082191782%\"\u003e\n \u003cp\u003e0.350\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" width=\"16.54373024236038%\"\u003e\n \u003cp\u003eODI, h\u003csup\u003e-1\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"11.9072708113804%\"\u003e\n \u003cp\u003e21 (13 - 27)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"11.801896733403582%\"\u003e\n \u003cp\u003e2 (1 - 4) *\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"11.275026343519494%\"\u003e\n \u003cp\u003e15 (12 - 25)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"8.535300316122234%\"\u003e\n \u003cp\u003e0.030\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"11.9072708113804%\"\u003e\n \u003cp\u003e19 (13 - 23)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"11.9072708113804%\"\u003e\n \u003cp\u003e17 (9 - 21)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"7.903055848261328%\"\u003e\n \u003cp\u003e0.019\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"8.219178082191782%\"\u003e\n \u003cp\u003e0.502\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n\u003c/table\u003e\n\u003cp\u003e\u003cstrong\u003eTable 3.\u003c/strong\u003e Comparisons of postoperative complications. Data are presented as median (interquartile range) or n (%).\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eICU intensive care unit.\u0026nbsp;\u003c/p\u003e\n\u003ctable border=\"1\" cellpadding=\"0\" cellspacing=\"0\" width=\"0\"\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd width=\"41.21287128712871%\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"23.019801980198018%\"\u003e\n \u003cp\u003eCPAP treatment group (n=15)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"26.361386138613863%\"\u003e\n \u003cp\u003eNon-CPAP treatment group (n=17)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"9.405940594059405%\"\u003e\n \u003cp\u003ep-value\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"41.21287128712871%\"\u003e\n \u003cp\u003eLength of stay\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"23.019801980198018%\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"26.361386138613863%\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"9.405940594059405%\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" width=\"41.21287128712871%\"\u003e\n \u003cp\u003eLength of total hospital stay (d)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"23.019801980198018%\"\u003e\n \u003cp\u003e25 (22 - 30)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"26.361386138613863%\"\u003e\n \u003cp\u003e28 (25 - 36)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"9.405940594059405%\"\u003e\n \u003cp\u003e0.082\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" width=\"41.21287128712871%\"\u003e\n \u003cp\u003eLength of preoperative stay (d)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"23.019801980198018%\"\u003e\n \u003cp\u003e12 (10 - 17)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"26.361386138613863%\"\u003e\n \u003cp\u003e13 (12 - 17)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"9.405940594059405%\"\u003e\n \u003cp\u003e0.455\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" width=\"41.21287128712871%\"\u003e\n \u003cp\u003eLength of postoperative stay (d)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"23.019801980198018%\"\u003e\n \u003cp\u003e12 (10 - 14)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"26.361386138613863%\"\u003e\n \u003cp\u003e15 (12 - 18)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"9.405940594059405%\"\u003e\n \u003cp\u003e\u003cstrong\u003e0.044\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" width=\"41.21287128712871%\"\u003e\n \u003cp\u003eLength of ICU stay (h)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"23.019801980198018%\"\u003e\n \u003cp\u003e22 (17 - 55)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"26.361386138613863%\"\u003e\n \u003cp\u003e36 (29 - 52)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"9.405940594059405%\"\u003e\n \u003cp\u003e\u003cstrong\u003e0.040\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" width=\"41.21287128712871%\"\u003e\n \u003cp\u003eCardiac complications\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"23.019801980198018%\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"26.361386138613863%\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"9.405940594059405%\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" width=\"41.21287128712871%\"\u003e\n \u003cp\u003ePostoperative\u0026nbsp;arrhythmia, n (%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"23.019801980198018%\"\u003e\n \u003cp\u003e9 (60)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"26.361386138613863%\"\u003e\n \u003cp\u003e10 (58.8)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"9.405940594059405%\"\u003e\n \u003cp\u003e1.000\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" width=\"41.21287128712871%\"\u003e\n \u003cp\u003ePacemaker use, n (%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"23.019801980198018%\"\u003e\n \u003cp\u003e2 (13.3)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"26.361386138613863%\"\u003e\n \u003cp\u003e2 (11.8)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"9.405940594059405%\"\u003e\n \u003cp\u003e1.000\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" width=\"41.21287128712871%\"\u003e\n \u003cp\u003eFirst dose of dopamine\u0026nbsp;in ICU (\u0026micro;g/kg\u0026middot;min)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"23.019801980198018%\"\u003e\n \u003cp\u003e4 (2 \u0026ndash; 5.5)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"26.361386138613863%\"\u003e\n \u003cp\u003e4 (3 - 5)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"9.405940594059405%\"\u003e\n \u003cp\u003e0.682\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" width=\"41.21287128712871%\"\u003e\n \u003cp\u003eFirst dose of dobutamine in ICU (\u0026micro;g/kg\u0026middot;min)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"23.019801980198018%\"\u003e\n \u003cp\u003e3 (2 - 5)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"26.361386138613863%\"\u003e\n \u003cp\u003e3 (2 \u0026ndash; 4.5)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"9.405940594059405%\"\u003e\n \u003cp\u003e0.455\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" width=\"41.21287128712871%\"\u003e\n \u003cp\u003eRespiratory complications\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"23.019801980198018%\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"26.361386138613863%\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"9.405940594059405%\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" width=\"41.21287128712871%\"\u003e\n \u003cp\u003eReintubation\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"23.019801980198018%\"\u003e\n \u003cp\u003e1 (6.7)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"26.361386138613863%\"\u003e\n \u003cp\u003e2 (11.8)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"9.405940594059405%\"\u003e\n \u003cp\u003e1.000\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" width=\"41.21287128712871%\"\u003e\n \u003cp\u003ePneumonia\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"23.019801980198018%\"\u003e\n \u003cp\u003e2 (13.3)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"26.361386138613863%\"\u003e\n \u003cp\u003e3 (17.6)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"9.405940594059405%\"\u003e\n \u003cp\u003e1.000\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" width=\"41.21287128712871%\"\u003e\n \u003cp\u003eDuration of mechanical ventilation (h)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"23.019801980198018%\"\u003e\n \u003cp\u003e17 (12 - 19)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"26.361386138613863%\"\u003e\n \u003cp\u003e24 (20 - 34)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" width=\"9.405940594059405%\"\u003e\n \u003cp\u003e\u003cstrong\u003e0.010\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n\u003c/table\u003e "}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":false,"hideJournal":true,"highlight":"","institution":"","isAcceptedByJournal":false,"isAuthorSuppliedPdf":false,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":false,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true},"keywords":"obstructive sleep apnea, CPAP, cardiac valve replacement, postoperative complication","lastPublishedDoi":"10.21203/rs.3.rs-1391530/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-1391530/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003eWhether preoperative continuous positive airway pressure (CPAP) treatment improves postoperative outcomes in patients undergoing cardiac valve replacement (CVR) remains unknown. This tudy was to evaluate the effects of 1-week perioperative auto-continuous positive airway pressure (CPAP) treatment on postoperative heart and pulmonary outcomes in patients with obstructive sleep apnea (OSA) and valvular heart disease. Thirty-two patients with OSA and valvular heart disease were randomly assigned to 1-week CPAP (n\u0026thinsp;=\u0026thinsp;15) group and non-CPAP treatments (n\u0026thinsp;=\u0026thinsp;17) group. After the treatment, all patients underwent CVR surgery. The length of ICU and hospital stays, postoperative cardiac and respiratory complications were assessed and compared between the two groups. The results showed there was no significant difference in the baseline characteristics between the CPAP and non-CPAP treatment groups. The length of postoperative ICU and hospital stays, as well as the duration of mechanical ventilation were significantly reduced in the CPAP treatment group compared to the non-CPAP treatment group; however, there were no significant differences in cardiac complications (postoperative arrhythmias, pacemaker use, first dose of dopamine in the ICU, and first dose of dobutamine in the ICU), and respiratory complications (reintubation and pneumonia). We conclused that in patients underwent CVR, preoperative use of auto-CPAP for OSA significantly decreased the duration of mechanical ventilation, and postoperative stays in the ICU and hospital, but did not have an association with postoperative arrhythmias, pacemaker use, reintubation, or pneumonia.\u003c/p\u003e","manuscriptTitle":"Impact of 1-week preoperative auto-CPAP treatment on postoperative outcomes in patients undergoing heart valve replacement surgery: a prospective randomized controlled trial","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2022-04-11 16:54:32","doi":"10.21203/rs.3.rs-1391530/v1","editorialEvents":[{"type":"communityComments","content":0}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true}}],"origin":"","ownerIdentity":"034f54bb-dc80-481d-aaaa-ad69f4f84daa","owner":[],"postedDate":"April 11th, 2022","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"posted","subjectAreas":[],"tags":[],"updatedAt":"2022-06-02T07:44:18+00:00","versionOfRecord":[],"versionCreatedAt":"2022-04-11 16:54:32","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-1391530","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-1391530","identity":"rs-1391530","version":["v1"]},"buildId":"_2-kVJe1T_tPrBINL-cwx","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}