Meta-analysis of the association between obstructive sleep apnoea and postoperative outcome

Society of Anesthesia and Sleep Medicine Guideline on Intraoperative Management of Adult Patients With Obstructive Sleep Apnea

The purpose of the Society of Anesthesia and Sleep Medicine Guideline on Intraoperative Management of Adult Patients With Obstructive Sleep Apnea (OSA) is to present recommendations based on current scientific evidence. This guideline seeks to address questions regarding the intraoperative care of patients with OSA, including airway management, anesthetic drug and agent effects, and choice of anesthesia type. Given the paucity of high-quality studies with regard to study design and execution in this perioperative field, recommendations were to a large part developed by subject-matter experts through consensus processes, taking into account the current scientific knowledge base and quality of evidence. This guideline may not be suitable for all clinical settings and patients and is not intended to define standards of care or absolute requirements for patient care; thus, assessment of appropriateness should be made on an individualized basis. Adherence to this guideline cannot guarantee successful outcomes, but recommendations should rather aid health care professionals and institutions to formulate plans and develop protocols for the improvement of the perioperative care of patients with OSA, considering patient-related factors, interventions, and resource availability. Given the groundwork of a comprehensive systematic literature review, these recommendations reflect the current state of knowledge and its interpretation by a group of experts at the time of publication. While periodic reevaluations of literature are needed, novel scientific evidence between updates should be taken into account. Deviations in practice from the guideline may be justifiable and should not be interpreted as a basis for claims of negligence.

A new sensitive and accurate model to predict moderate to severe obstructive sleep apnea in patients with obesity

Obstructive sleep apnea (OSA) has a high prevalence in patients with obesity. Only patients with clinical symptoms of OSA are admitted to polysomnography; however, many patients with OSA are asymptomatic. We aimed to create and validate a population-based risk score that predicts the severity of OSA in patients with obesity.We here report the cross-sectional analysis at baseline of an ongoing study investigating the long-term effect of bariatric surgery on OSA. One-hundred sixty-one patients of the Obesity Center of the Catholic University Hospital in Rome, Italy were included in the study. The patients underwent overnight cardiorespiratory monitoring, blood chemistry analyses, hepatic ultrasound, and anthropometric measurements. The patients were divided into 2 groups according OSA severity assessed by the apnea-hypopnea index (AHI): AHI < 15 = no or mild and AHI ≥ 15 moderate to severe OSA. A statistical prediction model was created and validated. C statistics was used to evaluate the discrimination performance of the model.The prevalence of OSA was 96.3% with 74.5% of the subjects having moderate/severe OSA. Sex, body mass index, diabetes, and age were included in the final prediction model that had excellent discrimination ability (C statistics equals to 83%). An OSA risk chart score for clinical use was created.Patients with severe obesity are at a very high risk for moderate or severe OSA in particular if they are men, older, more obese, and/or with type 2 diabetes. The OSA risk chart can be useful for general practitioners and patients as well as for bariatric surgeons to select patients with high risk of moderate to severe OSA for further polysomnography.

Evaluation of Neuromuscular Blockade Reversal on Postoperative Mechanical Ventilation Time in a Cardiovascular Surgery Population

OBJECTIVE

To report on postoperative outcomes related to the administration of neostigmine for reversal of nondepolarizing neuromuscular blocking agents in cardiovascular surgery patients, with a specific focus on the duration of postoperative mechanical ventilation as the primary endpoint.

DESIGN

A retrospective cohort study design was followed to achieve the study objectives.

SETTING

This was a single-center, chart review study conducted at a large academic medical center of adult patients post-cardiovascular surgery.

PARTICIPANTS

Patients were included if they had received a bolus dose of perioperative nondepolarizing neuromuscular blocking agent and underwent one of the targeted cardiovascular surgeries.

INTERVENTIONS

Final analysis comprised of 175 patients, 95 of whom received neostigmine and 80 who did not receive neostigmine.

MEASUREMENTS AND MAIN RESULTS

The primary endpoint was the duration of postoperative mechanical ventilation. When controlling for all covariates, neostigmine use was associated with a 0.34-hour reduction (∼20.4 min) in duration of mechanical ventilation (parameter estimate: 0.66, 95% confidence interval 0.49-0.89; p = 0.0071). More patients who received neostigmine met the early extubation benchmark of less than 6 hours (55 v 34 patients; p = 0.04). Finally, neostigmine use was not found to be associated with increased risk of respiratory complications or postoperative nausea and/or vomiting.

CONCLUSIONS

The use of neostigmine was found to have a protective effect on the duration of postoperative mechanical ventilation without increasing the risk of adverse complications.

Effect of Albuterol Premedication vs Placebo on the Occurrence of Respiratory Adverse Events in Children Undergoing Tonsillectomies: The REACT Randomized Clinical Trial

IMPORTANCE

Tonsillectomy is a common pediatric procedure for the treatment of sleep-disordered breathing and chronic tonsillitis. Up to half of children having this procedure experience a perioperative respiratory adverse event.

OBJECTIVE

To determine whether inhaled albuterol sulfate (salbutamol sulfate) premedication decreases the risk of perioperative respiratory adverse events in children undergoing anesthesia for tonsillectomy.

DESIGN, SETTING, AND PARTICIPANTS

A randomized, triple-blind, placebo-controlled trial (the Reducing Anesthetic Complications in Children Undergoing Tonsillectomies [REACT] trial) was conducted at Perth Children's Hospital (formerly Princess Margaret Hospital for Children), the only tertiary pediatric hospital in Western Australia. Participants included 484 children aged 0 to 8 years who were undergoing anesthesia for tonsillectomy. The study was conducted between July 15, 2014, and May 18, 2017.

INTERVENTIONS

Participants were randomized to receive either albuterol (2 actuations, 200 μg) or placebo before their surgery.

MAIN OUTCOMES AND MEASURES

Occurrence of perioperative respiratory adverse events (bronchospasm, laryngospasm, airway obstruction, desaturation, coughing, and stridor) until discharge from the postanesthesia care unit.

RESULTS

Of 484 randomized children (median [range] age, 5.6 [1.6-8.9] years; 285 [58.9%] boys), 479 data sets were available for intention-to-treat analysis. Perioperative respiratory adverse events occurred in 67 of 241 children (27.8%) receiving albuterol and 114 of 238 children (47.9%) receiving placebo. After adjusting for age, type of airway device, and severity of obstructive sleep apnea in a binary logistic regression model, the likelihood of perioperative respiratory adverse events remained significantly higher in the placebo group compared with the albuterol group (odds ratio, 2.8; 95% CI, 1.9-4.2; P < .001). Significant differences were seen in children receiving placebo vs albuterol in laryngospasm (28 [11.8%] vs 12 [5.0%]; P = .009), coughing (79 [33.2%] vs 27 [11.2%]; P < .001), and oxygen desaturation (54 [22.7%] vs 36 [14.9%]; P = .03).

CONCLUSIONS AND RELEVANCE

Albuterol premedication administered before tonsillectomy under general anesthesia in young children resulted in a clinically significant reduction in rates of perioperative respiratory adverse events compared with the rates in children who received placebo. Premedication with albuterol should be considered for children undergoing tonsillectomy.

TRIAL REGISTRATION

Australian New Zealand Clinical Trials Registry identifier: ACTRN12614000739617.

Obstructive sleep apnoea in adults: peri-operative considerations: A narrative review

: Obstructive sleep apnoea (OSA) is a common breathing disorder of sleep with a prevalence increasing in parallel with the worldwide rise in obesity. Alterations in sleep duration and architecture, hypersomnolence, abnormal gas exchange and also associated comorbidities may all feature in affected patients.The peri-operative period poses a special challenge for surgical patients with OSA who are often undiagnosed, and are at an increased risk for complications including pulmonary and cardiovascular, during that time. In order to ensure the best peri-operative management, anaesthetists caring for these patients should have a thorough understanding of the disorder, and be aware of the individual's peri-operative risk constellation, which depends on the severity and phenotype of OSA, the invasiveness of the surgical procedure, anaesthesia and also the requirement for postoperative opioids.The objective of this review is to educate clinicians in the epidemiology, pathogenesis and diagnosis of OSA in adults and also to highlight specific tasks in the preoperative assessment, namely to select a suitable intra-operative anaesthesia regimen, and manage the extent and duration of postoperative care to facilitate the best peri-operative outcome.

Association of Unrecognized Obstructive Sleep Apnea With Postoperative Cardiovascular Events in Patients Undergoing Major Noncardiac Surgery

Importance

Unrecognized obstructive sleep apnea increases cardiovascular risks in the general population, but whether obstructive sleep apnea poses a similar risk in the perioperative period remains uncertain.

Objectives

To determine the association between obstructive sleep apnea and 30-day risk of cardiovascular complications after major noncardiac surgery.

Design, Setting, and Participants

Prospective cohort study involving adult at-risk patients without prior diagnosis of sleep apnea and undergoing major noncardiac surgery from 8 hospitals in 5 countries between January 2012 and July 2017, with follow-up until August 2017. Postoperative monitoring included nocturnal pulse oximetry and measurement of cardiac troponin concentrations.

Exposures

Obstructive sleep apnea was classified as mild (respiratory event index [REI] 5-14.9 events/h), moderate (REI 15-30), and severe (REI >30), based on preoperative portable sleep monitoring.

Main Outcomes and Measures

The primary outcome was a composite of myocardial injury, cardiac death, heart failure, thromboembolism, atrial fibrillation, and stroke within 30 days of surgery. Proportional-hazards analysis was used to determine the association between obstructive sleep apnea and postoperative cardiovascular complications.

Results

Among a total of 1364 patients recruited for the study, 1218 patients (mean age, 67 [SD, 9] years; 40.2% women) were included in the analyses. At 30 days after surgery, rates of the primary outcome were 30.1% (41/136) for patients with severe OSA, 22.1% (52/235) for patients with moderate OSA, 19.0% (86/452) for patients with mild OSA, and 14.2% (56/395) for patients with no OSA. OSA was associated with higher risk for the primary outcome (adjusted hazard ratio [HR], 1.49 [95% CI, 1.19-2.01]; P = .01); however, the association was significant only among patients with severe OSA (adjusted HR, 2.23 [95% CI, 1.49-3.34]; P = .001) and not among those with moderate OSA (adjusted HR, 1.47 [95% CI, 0.98-2.09]; P = .07) or mild OSA (adjusted HR, 1.36 [95% CI, 0.97-1.91]; P = .08) (P = .01 for interaction). The mean cumulative duration of oxyhemoglobin desaturation less than 80% during the first 3 postoperative nights in patients with cardiovascular complications (23.1 [95% CI, 15.5-27.7] minutes) was longer than in those without (10.2 [95% CI, 7.8-10.9] minutes) (P < .001). No significant interaction effects on perioperative outcomes were observed with type of anesthesia, use of postoperative opioids, and supplemental oxygen therapy.

Conclusions and Relevance

Among at-risk adults undergoing major noncardiac surgery, unrecognized severe obstructive sleep apnea was significantly associated with increased risk of 30-day postoperative cardiovascular complications. Further research would be needed to assess whether interventions can modify this risk.

Obstructive sleep apnoea predicted by the STOP-BANG questionnaire is not associated with higher rates of post-operative complications among a high-risk surgical cohort

PURPOSE

The purpose of this study is to establish if obstructive sleep apnoea (OSA) predicted by the STOP-BANG questionnaire would be associated with higher rates of post-operative cardiac, respiratory or neurological complications among a selected high-risk population with established major comorbidities undergoing major surgery. We hypothesise that a cohort selected for major comorbidities will show a higher post-operative complication rate that may power any potential association with co-existent OSA and identify an important target group for OSA screening and treatment pathways in preparation for major surgery.

METHODS

Patients attending a high-risk preadmission clinic prior to major surgery from May 2015 to November 2015 were prospectively screened for OSA using the STOP-BANG questionnaire. Patients with treated OSA were excluded. Patient data and complications were attained from the pre-admission clinic and subsequent inpatient medical record at discharge.

RESULTS

Three-hundred-and-ten patients were included in the study (age 68.6 ± 13.1 years, body mass index [BMI] 30.6 ± 7.4 kg/m²; 52.9% female). Sixty-four patients (20.6%) experienced 82 post-operative complications. Seventy-five percent of the cohort had a STOP-BANG ≥ 3. There was no association between the STOP-BANG score (unadjusted and adjusted for comorbidity) with the development of post-operative complications.

CONCLUSIONS

OSA predicted by the STOP-BANG score was not associated with higher rates of post-operative complications in patients with major comorbidities undergoing high-risk surgery. As the findings from this cohort contrast with other observational studies, more definitive studies are required to establish a causative link between OSA and post-operative complications and determine whether treating OSA reduces this complication rate.

Identifying Patients Experiencing Opioid-Induced Respiratory Depression During Recovery From Anesthesia: The Application of Electronic Monitoring Devices

BACKGROUND

Postsurgical patients experiencing opioid-related adverse drug events have 55% longer hospital stays, 47% higher costs associated with their care, 36% increased risk of 30-day readmission, and 3.4 times higher risk of inpatient mortality compared to those with no opioid-related adverse drug events. Most of the adverse events are preventable.

GENERAL AIM

This study explored three types of electronic monitoring devices (pulse oximetry, capnography, and minute ventilation [MV]) to determine which were more effective at identifying the patient experiencing respiratory compromise and, further, to determine whether algorithms could be developed from the electronic monitoring data to aid in earlier detection of respiratory depression.

MATERIALS AND METHODS

A study was performed in the postanesthesia care unit (PACU) in an inner city. Sixty patients were recruited in the preoperative admissions department on the day of their surgery. Forty-eight of the 60 patients wore three types of electronic monitoring devices while they were recovering from back, neck, hip, or knee surgery. Machine learning models were used for the analysis.

RESULTS

Twenty-four of the 48 patients exhibited sustained signs of opioid-induced respiratory depression (OIRD). Although the SpO₂ values did not change, end-tidal CO₂ levels increased, and MV decreased, representing hypoventilation. A machine learning model was able to predict an OIRD event 10 min before the actual event occurred with 80% accuracy.

LINKING EVIDENCE TO ACTION

Electronic monitoring devices are currently used as a tool to assess respiratory status using thresholds to distinguish when respiratory depression has occurred. This study introduces a potential paradigm shift from a reactive approach to a proactive approach that would identify a patient at high risk for OIRD. Capnography and MV were found to be effective tools in detecting respiratory compromise in the PACU.

Outcomes and Complications After Spinal Fusion in Patients With Obstructive Sleep Apnea

STUDY DESIGN

Retrospective database study.

OBJECTIVE

To investigate the impact obstructive sleep apnea (OSA) has on perioperative complications, inpatient mortality, and costs in patients undergoing spinal fusions.

METHODS

Hospitalizations for spinal fusion surgery between the years 2009 and 2011 were identified using the Nationwide Inpatient Sample and grouped into patients with and without OSA. Patient demographic data, comorbidities, hospital characteristics, hospitalization outcomes, and costs were extracted and compared. Multivariable logistic regressions were conducted to compare the in-hospital outcomes of patients undergoing spinal fusion with and without OSA.

RESULTS

A total of 107 451 (7.7%) OSA patients who underwent spinal fusions were identified from 2009 to 2011. Compared with patients without OSA, OSA patients were significantly older, more likely to be male, and have significantly greater comorbidity burden. Multivariable regression analysis demonstrated that OSA had a significant independent association with slightly increased respiratory (odds ratio [OR] = 1.13, confidence interval [CI] = 1.09-1.16; P < .001), urinary and renal (OR = 1.11, CI = 1.07-1.16; P < .001) or overall inpatient complications (OR = 1.05, CI = 1.02-1.05; P < .001). OSA was also independently associated with significantly lower inpatient mortality (OR = 0.39, CI = 0.33-0.45; P < .001).

CONCLUSIONS

While OSA confers greater comorbidity burden and is associated with slightly higher inpatient complication rates following spinal fusions, diagnosed OSA was not an independent predictor of inpatient mortality. A cautious interpretation of this finding is that on a national level, the current methods of preoperative medical optimization and inpatient management of OSA are satisfactory.

Knowledge Gaps in the Perioperative Management of Adults with Obstructive Sleep Apnea and Obesity Hypoventilation Syndrome. An Official American Thoracic Society Workshop Report

The purpose of this workshop was to identify knowledge gaps in the perioperative management of obstructive sleep apnea (OSA) and obesity hypoventilation syndrome (OHS). A single-day meeting was held at the American Thoracic Society Conference in May, 2016, with representation from many specialties, including anesthesiology, perioperative medicine, sleep, and respiratory medicine. Further research is urgently needed as we look to improve health outcomes for these patients and reduce health care costs. There is currently insufficient evidence to guide screening and optimization of OSA and OHS in the perioperative setting to achieve these objectives. Patients who are at greatest risk of respiratory or cardiac complications related to OSA and OHS are not well defined, and the effectiveness of monitoring and other interventions remains to be determined. Centers involved in sleep research need to develop collaborative networks to allow multicenter studies to address the knowledge gaps identified below.

Pre-operative respiratory optimisation: an expert review

Postoperative pulmonary complications are common and cause increased mortality and hospital stay. Smoking and respiratory diseases including asthma, chronic obstructive pulmonary disease and obstructive sleep apnoea are associated with developing postoperative pulmonary complications. Independent risk factors for such complications also include low pre-operative oxygen saturation, or a recent respiratory infection. Postponing surgery in patients who have respiratory infections or inadequately treated respiratory disease, until these can be fully treated, should, therefore, reduce postoperative pulmonary complications. There is evidence from several studies that pre-operative smoking cessation reduces such complications, with no agreed duration at which the benefits become significant; the longer the abstinence, the greater the benefit. Intensive smoking cessation programmes are more effective, and there are long-term benefits, as many patients become permanent non-smokers following their surgery. Supervised exercise programmes normally last 6-8 weeks, and although they reduce overall complications, the evidence of benefit for postoperative pulmonary complications is mixed. High-intensity interval training can improve fitness in just 2 weeks, and so may be more useful for surgical patients. Specific respiratory pre-operative interventions, such as deep breathing exercises and incentive spirometry, can help when used as components of a package of respiratory care. Pre-operative inspiratory muscle training programmes that involve inspiration against a predetermined respiratory load may also reduce some postoperative pulmonary complications. Pre-operative exercise programmes are recommended for patients having major surgery, or in those where pre-operative testing has shown low levels of cardiorespiratory fitness; interval training or respiratory interventions are more feasible as these reduce complications after a shorter pre-operative intervention.

Preoperative Assessment of Obstructive Sleep Apnea in the Ambulatory Anesthesia Patient: A Survey of Oral and Maxillofacial Surgery Providers

PURPOSE

Oral and maxillofacial surgeons often treat patients with both diagnosed and undiagnosed obstructive sleep apnea (OSA). Patients with OSA are at substantial risk of perioperative and postoperative complications after receiving intravenous sedation, general anesthesia, or postoperative opiate analgesia. The purpose of this study was to determine whether oral and maxillofacial surgery (OMS) providers are screening patients for perioperative and postoperative risks related to OSA before office-based ambulatory anesthesia.

MATERIALS AND METHODS

SurveyMonkey software (SurveyMonkey, San Mateo, CA) was used to distribute a survey to 1,658 community- and hospital-based OMS providers in the United States. A response rate of 17.4% (n = 288) was achieved. The 27-question survey was created to obtain demographic information and to assess the preoperative anesthesia routine of the OMS providers. The questions were developed based on American Society of Anesthesiologists guidelines and the STOP-Bang questionnaire to determine the quality and rate of screening for OSA before office-based ambulatory anesthesia procedures.

RESULTS

All incomplete survey responses were excluded from analysis. Demographic analysis showed that 73.61% of the 288 respondents were in private practice only, with no hospital affiliation. Of the respondents, 81.88% reported performing fewer than 50 hospital operating room procedures per year, 81.60% reported performing more than 200 office-based ambulatory anesthesia cases per year, and 96.19% reported performing their own office-based ambulatory anesthesia. In this cohort, only 34.7% of OMS providers stated that they asked patients OSA-specific screening questions, whereas 74.3% reported asking other preoperative anesthesia questions (χ² = 91.0, df = 1, P < .0001).

CONCLUSIONS

Most of the surveyed OMS providers are not screening pre-anesthesia patients for OSA with a quantifiable method such as the STOP-Bang questionnaire. These findings identify a need to investigate the rate of undiagnosed OSA syndrome in the OMS office-based ambulatory anesthesia patient population. The STOP-Bang questionnaire may be a useful tool to better assess for anesthesia risk and modify management accordingly.

Perioperative impact of sleep apnea in a high-volume specialty practice with a strong focus on regional anesthesia: a database analysis

Background and objectives

Obstructive sleep apnea (OSA) is a risk factor for adverse postoperative outcome and perioperative professional societies recommend the use of regional anesthesia to minimize perioperative detriment. We studied the impact of OSA on postoperative complications in a high-volume orthopedic surgery practice, with a strong focus on regional anesthesia.

Methods

After Institutional Review Board approval, 41 766 cases of primary total hip and knee arthroplasties (THAs/TKAs) from 2005 to 2014 were extracted from institutional data of the Hospital for Special Surgery (approximately 5000 THAs and 5000 TKAs annually, of which around 90% under neuraxial anesthesia).

The main effect was OSA (identified by the International Classification of Diseases, ninth revision codes); outcomes of interest were cardiac, pulmonary, gastrointestinal, renal/genitourinary, thromboembolic complications, delirium, and prolonged length of stay (LOS). Multivariable logistic regression models provided ORs, corresponding 95% CIs, and p values.

Results

Overall, OSA was seen in 6.3% (n=1332) of patients with THA and 9.1% (n=1896) of patients with TKA. After adjustment for relevant covariates, OSA was significantly associated with 87% (OR 1.87, 95% CI 1.51 to 2.30), 52% (OR 1.52, 95% CI 1.13 to 2.04), and 44% (OR 1.44,95% CI 1.31 to 1.57) increased odds for pulmonary gastrointestinal complications, and prolonged LOS, respectively. The odds for other outcomes remained unaltered by OSA diagnosis.

Conclusion

We showed that, even in a setting with almost universal regional anesthesia use, OSA was associated with increased odds for prolonged LOS, and pulmonary and gastrointestinal complications. This puts forward the question of how effective regional anesthesia is in mitigating postoperative complications in patients with OSA.

Postoperative sleep disorders and their potential impacts on surgical outcomes

Postoperative sleep disturbance is a common occurrence with significant adverse effects on patients including delayed recovery, impairment of cognitive function, pain sensitivity and cardiovascular events. The development of postoperative sleep disturbance is multifactorial and involves the surgical inflammatory response, the severity of surgical trauma, pain, anxiety, the use of anesthetics and environmental factors such as nocturnal noise and light levels. Many of these factors can be managed perioperatively to minimize the deleterious impact on sleep. Pharmacological and non-pharmacological treatment strategies for postoperative sleep disturbance include dexmedetomidine, zolpidem, melatonin, enhanced recovery after surgery (ERAS) protocol and controlling of environmental noise and light levels. It is likely that a combination of pharmacological and non-pharmacological therapies will have the greatest impact; however, further research is required before their use can be routinely recommended.

Preoperative Evaluation: Estimation of Pulmonary Risk Including Obstructive Sleep Apnea Impact

One in 4 deaths occurring within a week of surgery are related to pulmonary complications, making it the second most common serious morbidity after cardiovascular events. The most significant predictors of the postoperative pulmonary complications (PPCs) are American Society of Anesthesiologists physical status, advanced age, dependent functional status, surgical site, and duration of surgery. The overall risk of PPCs can be predicted using scores that incorporate readily available clinical data.

Effects of continuous positive airway pressure in patients at high risk of obstructive sleep apnea during propofol sedation after spinal anesthesia

In patients with obstructive sleep apnea, short-term use of a continuous positive airway pressure mask improves oxygenation, decreases the apnea-hypopnea index, and reduces hemodynamic instability. In this study, we investigated the effects of use of a continuous positive airway pressure mask in patients at high risk of obstructive sleep apnea during propofol sedation after spinal anesthesia. Forty patients who underwent propofol sedation after spinal anesthesia for transurethral bladder or prostate resection with a STOP-Bang score of 3 or more were enrolled in this study. Patients were randomly divided into two groups: a simple oxygen mask group (n = 20) and a continuous positive airway pressure mask group (n = 20). After spinal anesthesia, propofol was injected at a target concentration of 1.3 mcg/ml via a target concentration control injector. ApneaLink™ was applied to all patients. Patients in the simple oxygen mask group were administered oxygen at a rate of 6 L/min through a simple facial mask. Patients in the CPAP mask group were connected to a pressurizer, and oxygen (6 L/min, 5-15 cm H₂O) was administered. Blood pressure, heart rate, respiratory rate, and oxygen saturation were recorded preoperatively, after spinal anesthesia, and every 5 min after the injection of propofol to observe hemodynamic changes. Apnea-hypopnea index was estimated using ApneaLink™. There were no significant differences in hemodynamic changes between the two groups. Apnea-hypopnea index was significantly reduced in the continuous positive airway pressure mask group compared to the simple facial mask group. Application of a continuous positive airway pressure mask in a patient at high risk of obstructive sleep apnea can lower the incidence of obstructive sleep apnea during sedation without a significant effect on hemodynamic stability.

Preventing Opioid-Induced Respiratory Depression in the Hospitalized Patient With Obstructive Sleep Apnea

PURPOSE

To enhance the role of nursing interventions in the management of perioperative opioid-induced respiratory depression (OIRD) in patients with obstructive sleep apnea (OSA).

DESIGN

Narrative review of the literature.

METHODS

Literature reviewed with emphasis on recommendations by professional and accrediting organizations.

FINDINGS

Postsurgical OIRD increases hospital stay (55%), cost of care (47%), 30-day readmission (36%), and inpatient mortality (3.4 fold). OSA increases the risk of OIRD and may result in legal claims averaging $2.5 million per legal claim.

CONCLUSIONS

Nursing interventions are essential to improving outcome and reduce cost in the management of postsurgical OIRD in OSA patients.

Clinical Indicators of the Need for Telemetry Postoperative Monitoring in Patients With Suspected Obstructive Sleep Apnea Undergoing Total Knee Arthroplasty

BACKGROUND AND OBJECTIVES

Obstructive sleep apnea is associated with increased complication rates postoperatively. Current literature does not provide adequate guidance on management of these patients. This study used the STOP-Bang questionnaire to diagnose patients with possible obstructive sleep apnea (score ≥3). We hypothesized that a STOP-Bang score of 3 or greater would significantly correlate with the number of oxygen desaturation episodes during the first 48 hours after total knee arthroscopy.

METHODS

The STOP-Bang questionnaire was administered to 110 patients preoperatively. All patients underwent spinal-epidural anesthesia with a saphenous nerve block and sedation and were connected to the Nellcor OxiMax N-600x pulse oximeter for 48 hours postoperatively.

RESULTS

Final analysis included 98 patients. There was no significant difference in the total number of desaturation events between STOP-Bang groups (score <3 vs ≥3 and score <5 vs ≥5). The total number of desaturation events on postoperative day 1 was greater than that on day 0 (32.8 ± 42.7 vs 4.1 ± 10.0, P < 0.0001). The total number of desaturation events correlated with length of hospital stay (r = 0.329, P = 0.0001). Patients with a preoperative serum CO2 of 30 mmol/L or greater had significantly longer episodes of desaturation on postoperative day 0 compared with CO2 of less than 30 mmol/L (233.7 ± 410.1 vs 82.0 ± 126.2 seconds, P = 0.044).

CONCLUSIONS

A high preoperative value of CO2 should be a warning for possible prolonged episodes of desaturation postoperatively. An attempt to limit postoperative desaturation events should be made to minimize length of stay.

Patient preference survey: are patients willing to delay surgery if obstructive sleep apnea is suspected?

BACKGROUND

Screening and optimizing patients for OSA in the perioperative period may reduce postoperative complications. However, sleep studies can be difficult to obtain before surgery. Previous surveys reported that the majority of sleep physicians would delay surgery to diagnose and manage OSA, but most anesthesiologists would not. While disagreements exist, the importance of shared decision making and patient preferences have never been studied on this topic. It is unknown whether patients with suspected OSA, when given information about OSA, would be willing to delay surgery to diagnose and manage their condition preoperatively.

METHODS

This study consisted of a self-administered questionnaire that surveyed patients, patient relatives, or any accompanying members. The survey was conducted in the preoperative clinic or in the perioperative patient and family waiting area at two hospitals in Canada and in the United States. A hypothetical scenario was used: participants were given information about OSA, and asked about their preferences regarding preoperative management should they be at risk for OSA in the setting of pending elective surgery. The objective of this study was to determine whether respondents preferred to 1) proceed with surgery as planned, 2) delay surgery to ensure the medical condition of OSA is diagnosed and optimized, or 3) let his/her physician decide.

RESULTS

The final survey contained 19 questions and the survey was conducted from June 2016 to September 2016. Four hundred and seventy-three surveys were collected. Forty-four percent of respondents, when given information about OSA, preferred to delay surgery pending a sleep study and treatment. Forty percent of respondents who preferred to delay surgery would tolerate delaying up to two months.

CONCLUSION

Increasing emphasis and significant value has been placed on shared-decision making between patients and physicians. Educating patients about the risks of OSA and incorporating patient preferences into the perioperative management of OSA may be warranted.

Clinical use of the STOP-BANG questionnaire to determine postoperative risk in veterans

OBJECTIVES

To determine whether STOP-BANG (snoring, tiredness, observed apnea, high blood pressure, body mass index, age, neck circumference, gender) scores are associated with immediate postoperative adverse events in veterans undergoing surgery.

METHODS

In this prospective cohort study, veterans presenting to the presurgical clinic at a Veterans Affairs hospital answered the STOP-BANG questionnaire, which was scored as high risk (5-8), intermediate risk (3-4), and low risk (0-2) for obstructive sleep apnea (OSA), during a 6-month study period. Immediate postoperative respiratory and cardiovascular adverse events were recorded.

RESULTS

The patient population included 1,080 veterans. Ninety-five patients (8.8%) experienced adverse events, of which 74 (6.9%) were respiratory and 21 (1.9%) were cardiovascular in nature. Patients with high-risk STOP-BANG scores (5-8) had significantly greater odds of having an adverse event odds ratio (OR) 2.1 (95% confidence interval [CI]: 1.4, 3.3) and hypoxia OR 2.8 (95% CI: 1.7, 4.6) compared to those with low- to intermediate-risk scores (0-4). Among patients with OSA, those with high-risk scores (5-8) had greater odds of an adverse event OR 3.9 (95% CI: 1.1, 13.9) and hypoxia OR 3.7 (95% CI: 1.1, 13.0) compared to those with low- to intermediate-risk scores (0-4). Patients without a history of OSA with high-risk scores (5-8) did not have significantly greater odds of an adverse event OR 1.5 (95% CI: 0.82, 2.6) or a hypoxic event OR 1.7 (95% CI: 0.87, 3.4) compared to those with low- to intermediate-risk scores (0-4).

CONCLUSION

The STOP-BANG questionnaire was useful in the veteran population because high-risk scores were predictive of adverse events, in particular, hypoxia for patients with a previous diagnosis of OSA. In the future, this may direct studies and clinical activities aimed at optimizing safe and effective perioperative practices.

LEVEL OF EVIDENCE

2b Laryngoscope, 129:259-264, 2019.

Evaluation of Epworth Sleepiness Scale to Predict Obstructive Sleep Apnea in Morbidly Obese Patients and Increasing Its Utility

INTRODUCTION

Studies have shown that Epworth sleepiness scale (ESS) is not a good tool to predict obstructive sleep apnea (OSA). However, data regarding the accuracy of ESS in the prediction of OSA among morbidly obese patients are scarce.

METHODS

The study involved a retrospective review of the charts of the consecutive patients who underwent bariatric surgery at a tertiary care teaching hospital. All the patients underwent polysomnography (PSG) and undertook the ESS questionnaire. The sensitivity and specificity of ESS were calculated based on its correlation with the PSG findings. Furthermore, a new score was devised to improve the utility of ESS to predict OSA.

RESULTS

A total of 232 consecutive patients from January 2014 to July 2017 were included in the study. The mean age and body mass index (BMI) were 40.5 ± 11.8 years and 47.6 ± 7.3 kg/m², respectively. Among the 162 patients who had an ESS <10, 57.4% had moderate-to-severe OSA. The sensitivity of ESS to predict moderate-to-severe OSA was found to be 38.8% and the positive predictive value was 84.2% (positive likelihood ratio 2.82, 95% confidence interval = 1.57-5.06). A predictive score was identified as 0.031Age (years) +0.039BMI (kg/m²) + 0.038ESS + Gender (1 for male, 0 for female). The score had a sensitivity of 80% at a cutoff of 3.3.

CONCLUSIONS

Among the morbidly obese, ESS is a poor predictor of OSA. Its utility as a tool for prediction of moderate-to-severe OSA can be improved by use of a new formula incorporating age, gender, and BMI beside ESS.

An update on the various practical applications of the STOP-Bang questionnaire in anesthesia, surgery, and perioperative medicine

Purpose of review

The present review aims to provide an update on the various practical applications of the STOP-Bang questionnaire in anesthesia, surgery, and perioperative medicine.

Recent findings

The STOP-Bang questionnaire was originally validated as a screening tool to identify surgical patients who are at high-risk of obstructive sleep apnea (OSA). A recent meta-analysis confirmed that STOP-Bang is validated for use in the sleep clinic, surgical, and general population. Patients with a STOP-Bang score of 0--2 can be classified as low-risk for moderate-to-severe OSA. Those with a score of 5--8 can be classified as high-risk for moderate-to-severe OSA. In patients with a score of 3 or 4, a specific combination of a STOP score at least 2 + BMI more than 35 kg/m² or STOP score at least 2 + male or STOP score at least 2 + neck circumference more than 40 cm indicates higher risk for moderate-to-severe OSA. Further, patients with a STOP-Bang score at least 3 can be classified as high risk for moderate-to-severe OSA if the serum HCO₃^- at least 28 mmol/l. STOP-Bang can be used as a novel tool for perioperative risk stratification because it easily identifies patients who are at increased risk of perioperative complications.

Summary

STOP-Bang at least 3 was recommended previously to identify the suspected or undiagnosed OSA. To reduce the false positive cases and to improve its specificity, a stepwise stratification is recommended to identify the patients at high risk of moderate-to-severe OSA. Because of its practical application, STOP-Bang is a useful screening tool for patients with suspected or undiagnosed OSA.

Preoperative obstructive sleep apnea screening in gynecologic oncology patients

BACKGROUND

Women with a gynecologic cancer tend to be older, obese, and postmenopausal, characteristics that are associated with an increased risk for obstructive sleep apnea. However, there is limited investigation regarding the condition's prevalence in this population or its impact on postoperative outcomes. In other surgical populations, patients with obstructive sleep apnea have been observed to be at increased risk for adverse postoperative events.

OBJECTIVE

We sought to estimate the prevalence of obstructive sleep apnea among gynecologic oncology patients undergoing elective surgery and to investigate for a relationship between obstructive sleep apnea and postoperative outcomes.

STUDY DESIGN

Patients referred to an academic gynecologic oncology practice were approached for enrollment in this prospective, observational study. Patients were considered eligible for study enrollment if they were scheduled for a nonemergent inpatient surgery and could provide informed consent. Enrolled patients were evaluated for a preexisting diagnosis of obstructive sleep apnea. Those without a prior diagnosis were screened using the validated, 4-item STOP questionnaire (ie, Snore loudly, daytime Tiredness, Observed apnea, elevated blood Pressure). All patients who screened positive for obstructive sleep apnea were referred for polysomnography. The primary outcome was the prevalence of women with obstructive sleep apnea or those who screened at high risk for the condition. Secondary outcomes examined the correlation between body mass index (kg/m²) with obstructive sleep apnea and assessed for a relationship between obstructive sleep apnea and postoperative outcomes.

RESULTS

Over a 22-month accrual period, 383 eligible patients were consecutively approached to participate in the study. A cohort of 260 patients were enrolled. A total of 33/260 patients (13%) were identified as having a previous diagnosis of obstructive sleep apnea. An additional 66/260 (25%) screened at risk for the condition using the STOP questionnaire. Of the patients who screened positive, 8/66 (12%) completed polysomnography, all of whom (8/8 [100%]) were found to have obstructive sleep apnea. The prevalence of previously diagnosed obstructive sleep apnea or screening at risk for the condition increased as body mass index increased (P < .001). Women with untreated obstructive sleep apnea and those who screened at risk for the condition were found to have an increased risk for postoperative hypoxemia (odds ratio, 3.5; 95% confidence interval, 1.8-4.7; P = .011) and delayed return of bowel function (odds ratio, 2.1; 95% confidence interval, 1.3-4.5; P = .009).

CONCLUSION

The prevalence of obstructive sleep apnea or screening at risk for the condition is high among women presenting for surgery with a gynecologic oncologist. Providers should consider evaluating a patient's risk for obstructive sleep apnea in the preoperative setting, especially when risk factors for the condition are present.

Using the Electronic Medical Record to Improve Preoperative Identification of Patients at Risk for Obstructive Sleep Apnea

PURPOSE

Obstructive sleep apnea (OSA) is a breathing disorder found in surgical patients and associated with complications in the postoperative period. The implementation of a preoperative universal screening process using the STOP-BANG questionnaire to identify patients at high risk for OSA provides opportunities for improved management.

DESIGN

A pre-post design was used to evaluate screening compliance rates.

METHODS

This initiative included staff education, which included the process for evaluating and documenting STOP-BANG scores. The data were collected via a chart review of the electronic medical record (EMR).

FINDINGS

The rate of screening for OSA doubled after implementation of this initiative, and compliance with STOP-BANG questionnaire screening was 66.1%. High-risk designation in the EMR was 73.0%. Nearly half of the patients screened were found to be at high risk for OSA.

CONCLUSIONS

Implementation of a universal screening initiative for patients and design for the EMR improves compliance with screening and identification of patients at high risk for OSA.

Postoperative complications after elective coronary artery bypass grafting surgery in patients with sleep-disordered breathing

BACKGROUND

Sleep-disordered breathing (SDB) may increase the risk of postoperative complications in patients after cardiac surgery. This study evaluated the length of hospital stay as well as postoperative cardiac, respiratory, and renal complications after elective coronary artery bypass grafting (CABG) in patients without SDB, with central sleep apnea (CSA), or with obstructive sleep apnea (OSA).

METHODS

The presence and type of SDB had been assessed with polygraphic recordings in 100 patients the night before elective CABG surgery. SDB was defined as an apnea-hypopnea index (AHI) of ≥ 15/h. Prolonged length of hospital stay (LOS) and postoperative hemodynamic instability due to any cause were retrospectively evaluated as primary endpoints and cardiac, respiratory, and renal complications as secondary endpoints.

RESULTS

37% of patients had SDB, 14% CSA, and 23% OSA. LOS differed significantly between patients without SDB and those with CSA and OSA [median (25;75. percentile): 8.0 days (7.5;11.0) vs. 9.5 days (7.0;12.5) vs. 12.0 days (9.0;17.0), Kruskal-Wallis test between three groups: p = 0.023; OSA vs. no SDB: p = 0.005]. AHI was significantly associated with prolonged LOS [> 9 days; odds ratio (OR) (95% confidence interval): 1.047 (1.001;1.095), p = 0.044]. Prolonged need of vasopressors (≥ 48 h) was observed in 36% of patients without SDB, in 64% with CSA, and in 62% with OSA (p = 0.037). AHI was significantly associated with prolonged (≥ 48 h) need of vasopressors [OR (95% CI): 1.052 (1.002;1.104), p = 0.040], independent of any confounders.

CONCLUSIONS

SDB, particularly OSA, is associated with prolonged LOS after CABG, independent of known confounders. Prolonged LOS in patients with SDB may be due to increased postoperative hemodynamic instability due to any cause.

Sleep disorder diagnoses and clinical outcomes among hospitalized breast cancer patients: a nationwide inpatient sample study

PURPOSE

Sleep disturbances are recognized as a problem for many cancer patients, but little is known about the prevalence of sleep disorders among women hospitalized with breast cancer, or their relationship to in-hospital outcomes. The present study represents a first step toward determining the clinical significance of sleep disorders for hospitalized breast cancer patients with regard to complications, length of hospital stay, and mortality.

METHODS

The relationships between sleep disorders and in-hospital outcomes among 84,424 hospitalized breast cancer patients were examined. This study analyzed the Nationwide Inpatient Sample (NIS) database (2007 to 2011) for all women ages 40 years and older with a primary discharge diagnosis of breast cancer and a secondary discharge diagnosis of sleep disorder. Odds ratios, estimates, and 95% confidence intervals were computed using multivariable regression adjusting for age, comorbidities, race, cancer stage, income, insurance type, residential region, year of discharge, and surgical treatment type.

RESULTS

Among women hospitalized with a primary diagnosis of breast cancer, 2% (n = 1807) also received a diagnosis of a sleep disorder during hospitalization, the majority of which were sleep-related breathing disorders (n = 1274). Although there was no significant association between having a diagnosis of a sleep disorder and in-hospital mortality, patients with a sleep disorder were more likely to also experience complications (OR = 1.58, 95% CI 1.29-1.34) and have longer hospital stays (mean = 0.44 days longer, 95% CI 0.25-0.63).

CONCLUSION

Hospitalized breast cancer patients with a sleep disorder were more likely to experience clinical complications and stay longer in the hospital. It remains an open and important question for future research whether interventions to improve sleep during hospitalization would help to improve clinical outcomes.

Controversies in office-based anesthesia: obstructive sleep apnea considerations

As the number of procedures being performed in the office-based anesthesia (OBA) setting are increasing, so are the number of patients presenting for surgery with obstructive sleep apnea (OSA). There continues to be controversy regarding whether these patients can be safely cared for in the OBA setting. To date, no national guideline has clearly addressed this issue and while some have extrapolated lessons from what has been published for OSA in the ambulatory surgery center (ASC) setting, some argue that there is a significant difference in the availability of resources in the ASC versus the OBA setting. Those opposing OSA patients for OBA setting point to the prevalence of "practice drift," and no federal oversight as overarching reasons why the OBA is not an appropriate setting. Proponents of the OBA setting argue that a well-equipped OBA can have similar resources, and therefore similar outcomes, as an OR in the ASC setting. In this paper we explore the divergent views on this topic and present some recommendations based on best evidence.

Usefulness of the STOP-Bang Questionnaire in a Cardiac Surgical Population

OBJECTIVE

The aim of this study was to assess the predictive accuracy of the STOP-Bang questionnaire in relation to obstructive sleep apnea (OSA) detected by nocturnal oximetry, as well as postoperative outcomes, in a population undergoing cardiac surgery.

DESIGN

A prospective observational cohort study.

SETTING

The specialist cardiothoracic center at the Royal Papworth Hospital, Cambridge University Health Partners, United Kingdom.

PARTICIPANTS

All adult patients, undergoing elective coronary artery bypass grafting with or without cardiac valve surgery between March 2013 and July 2014 were included. The authors excluded patients participating in other interventional studies, those who had a tracheostomy before surgery, and those who required emergency surgery or were due to be admitted on the day of surgery.

INTERVENTIONS

None.

MEASUREMENTS AND RESULTS

Cardiac surgical patients were screened for the risk of OSA with the use of STOP-Bang questionnaire. The presence of OSA prior to surgery was assessed with overnight oximetry. The predictive performance of the STOP-Bang questionnaire was assessed by calculating sensitivity, specificity, positive predictive value, negative predictive value, and area under the curve (AUC)-receiver operating characteristic curve (ROC). Multiple-logistic regression models were used to assess for associations between the STOP-Bang scores and postoperative outcomes. The STOP-Bang questionnaire discriminated poorly between mild OSA (AUC-ROC 0.57 [95% confidence interval (CI) 0.47-0.67]) and moderate/severe OSA (AUC-ROC 0.82 (95% CI 0.69-0.95)]. Accuracy was increased by modifying the cut-off value to 6 or greater, with sensitivity and specificity of 75% and 77%, respectively. A STOP-Bang score indicating the possibility of OSA was not significantly associated with prolonged intensive care unit lengths of stay (hazard ratio [HR] 1.1; 95% CI 0.99-1.19; p = 0.08) or postoperative complications (odds ratio [OR] 1.0; 95% CI 0.59-1.72; p = 0.98).

CONCLUSIONS

In the study population, a STOP-Bang questionnaire score of 3 or greater had limited predictive value for identifying cardiac surgical patients at high risk of OSA. STOP-Bang scores were not significantly associated with worse postoperative outcomes. A STOP-Bang score of 6 or greater could help identify patients in need of a sleep study to confirm the presence of OSA as such patients may be at increased risk of postoperative complications.

Perianesthesia Nurses' Survey of Their Knowledge and Practice With Obstructive Sleep Apnea

PURPOSE

Anesthesia, sedation, and analgesia can negatively impact adult patients with obstructive sleep apnea (OSA). Despite known risks, current evidence, and practice guidelines, insufficient evidence exists that standardization and clinical application of OSA screening tools, problem identification, and perioperative nursing intervention and management strategies are consistently implemented for OSA patients across perianesthesia settings. The purpose of this study was to conduct a knowledge and practice assessment of perianesthesia nurses who care for adult patients with diagnosed or undiagnosed OSA.

DESIGN

An anonymous descriptive study was used to survey perianesthesia nurses who care for adult patients with OSA who present for elective surgical procedures.

METHODS

A total of 1,222 participants completed an expert-developed 27-question online survey.

FINDINGS

The findings indicate the need for more education and research across all perianesthesia settings.

CONCLUSIONS

Next steps also include policy development and an interprofessional collaborative infrastructure nurses need to translate evidence-based screening and management strategies into their clinical practice.

Evaluation of the pharyngeal airway using computational fluid dynamics in patients with acromegaly

Objectives

Perioperative airway management may be particularly challenging in patients with acromegaly undergoing trans‐sphenoidal pituitary surgery (TSS). Management for airway obstruction is required prior to pituitary surgery to minimize perioperative hypoxia. The purpose of this retrospective study was to evaluate airway obstruction by simulation of computational fluid dynamics (CFD) using computed tomography (CT) images in patients who had undergone TSS.

Methods

CT images of the nasopharyngeal airways of patients with acromegaly (n = 5) or nonfunctional pituitary adenoma (n = 6) undergoing TSS from April 2012 to January 2017 were used to construct these airways in three dimensions. Estimated airflow pressure and velocity in the retropalatal airway (RA), oropharyngeal airway (OA), and hypopharyngeal airway (HA) were simulated using CFD.

Results

Estimated pharyngeal airflow pressure in the HA, OA, and RA was significantly greater in patients with acromegaly than in those with nonfunctional pituitary adenomas whereas the estimated pharyngeal airflow velocity was significantly impaired only in the RA of patients with acromegaly. Minimum postoperative SpO₂ both within 3 hours and from 3 to 12 hours after the end of anesthesia was significantly lower in the patients with acromegaly. Additionally, estimated volume of tongue and pharyngeal airflow pressure in the HA, OA, and RA correlated with minimum postoperative SpO₂.

Conclusion

Pharyngeal airflow pressure estimated from CT images is high in patients with acromegaly, and these values correlate with postoperative minimum values for SpO₂. Preoperative evaluation of CT images by CFD can predict difficulty in airway management and perioperative hypoxia.

Level of Evidence

4.

BMI 35 kg/m2 does not fit everyone: a modified STOP-Bang questionnaire for sleep apnea screening in the Chinese population

PURPOSE

The STOP-Bang questionnaire is the most widely used to detect surgical patients at high risk of obstructive sleep apnea (OSA). However, the body mass index (BMI) cutoff value in the original STOP-Bang questionnaire is 35 kg/m²; the BMI in the Chinese population is lower than that. We aimed to establish a more appropriate BMI cutoff value in the STOP-Bang questionnaire for Chinese patients.

METHODS

A total of 790 consecutive patients scheduled to undergo surgery at our hospital were included in this prospective study. All patients were asked to complete the STOP-Bang questionnaire and undergo a 7-h overnight polysomnography (PSG). The ability of STOP-Bang questionnaire to detect moderate to severe OSA (AHI ≥ 15 events/h) was assessed.

RESULTS

When the BMI cutoff value was set at 28 kg/m², the questionnaire had the highest Youden index, although no significant differences were found in the sensitivity of the test compared with the original BMI cutoff in total and in male patients. In females, changing the BMI cutoff value from 35 to 28 kg/m² resulted in the sensitivity of the test significantly increasing from 79.2% (74.9-83.5) to 89.3% (84.4-94.1), while the decrease in specificity was minor (from 43.6% [41.2-46.0] to 38.2% [36.1-40.3]), and the Youden index was highest (0.27) at this cutoff value. When the STOP-Bang questionnaire score was 4, the highest Youden index was obtained.

CONCLUSIONS

We recommend using a BMI cutoff value (28 kg/m²), and a STOP-Bang score ≥ 4 allows the anesthetist to identify patients with high risk of OSA.

Peri-operative treatment of sleep-disordered breathing and outcomes in bariatric patients

Background

Obstructive sleep apnoea (OSA) is increasingly common in bariatric patients undergoing sedation during elective surgery. However, it has not been established how significant a contributor it is to peri-operative respiratory complications and mortality. We sought to pre-operatively identify OSA in bariatric patients and record peri-operative complications during and after bariatric surgery.

Methods

Data were collected and analysed from June 2014 to March 2017 for 410 bariatric surgery patients referred to the sleep laboratory for pre-operative screening and treatment of OSA. The STOP-Bang questionnaire, Epworth Sleepiness Scale (ESS) and nocturnal pulse oximetry were recorded and treatment was allocated with continuous positive airway pressure (CPAP). Peri-operative complications and mortality were the primary outcome measures for patients receiving CPAP treatment for OSA, with patients who did not require CPAP used as control. The mean follow-up time for all patients was 433 and 732 days for the patients who had undergone bariatric surgery. The two groups were compared with Chi square test and unpaired two-tailed t-test.

Results

OSA was present in any form in 70% of the screened patients; 40% of patients involved in the study received CPAP treatment. Patients receiving CPAP treatment [49.5 (11.3) years old, 61% female, 50.3 (8.5) kg/m²] were older, had a lower percentage of females and had a higher body mass index (BMI) than those not receiving CPAP [44.9 (12.0), 81% female, 46.6 (7.7)]. No significant differences were observed between patients on CPAP and those not on CPAP, there was no significant difference in hospital stay or rate of respiratory complications. Out of 53 patients who had undergone bariatric surgery at the cut-off date, only 1 had suffered a respiratory complication.

Conclusions

Bariatric patients who are screened pre-operatively for OSA and treated according to guidelines have no increased risk of respiratory complications compared to patients without OSA.

Assessment of perioperative difficult airway among undiagnosed obstructive sleep apnoea patients undergoing elective surgery: A prospective cohort study

Background and Aims:

Obstructive sleep apnoea (OSA) is largely undiagnosed in surgical population. Airway-related complication account for 35% of anaesthesia-related deaths and OSA patients have higher occurrence of difficult intubation (DIT). The aim of the study is to estimate the occurrence and compare utility of OSA screening parameters in predicting difficult mask ventilation (DMV) and DIT in patients with undiagnosed OSA.

Methods:

A prospective observational study was conducted in a tertiary care centre in patients undergoing elective surgery. STOP-BANG questionnaire was administered preoperatively along with collection of demographic data and airway assessment. Population was divided in to OSA and non-OSA groups based on STOP-BANG score >3. Occurrence of DMV, laryngoscopy (DL), and DIT were compared between both groups using DMV score, Cormack–Lehane grading, and intubation difficulty scale score, respectively.

Results:

A total of 54 patients in OSA and 46 patients in non-OSA group were studied. A total of 49 cases of DMV, 14 cases of DIT, and 25 cases of DL were encountered. In the OSA group, there was 77.7% DMV, 22.2% DIT, and 33.3% DL. History of snoring had the highest sensitivity and negative predictive value while history of apnea, body mass index >35, sleep apnoea clinical score had the highest specificity in determining occurrence of difficult airway. Multivariate logistic regression analysis demonstrated STOP-BANG score as the single most important predictor of DMV (odds ratio 3.15, 95% confidence interval, 2.06–4.8).

Conclusion:

Positive screening test for OSA is associated with difficult airway management.