The impact of sleep apnea on postoperative utilization of resources and adverse outcomes

Sleep Apnea is Not an Obstacle for Outpatient Hip and Knee Arthroplasty

BACKGROUND

Up to 25% of patients requiring hip or knee arthroplasty have sleep apnea (SA), and these patients have historically been excluded from outpatient programs. The objectives of this study were to evaluate same-day discharge failure as well as 30-day complications, readmissions, and unexpected visits.

METHODS

A retrospective case-control study comparing patients who have and do not have SA matched for age, sex and arthroplasty type (total hip arthroplasty, total knee arthroplasty, unicompartimental knee arthroplasty) who underwent primary outpatient surgery between February 2019 and December 2022 in 2 academic hospitals was conducted. Cases with mild SA, moderate SA with a body mass index (BMI) <35, and SA of all severity treated by continuous positive airway pressure machines were eligible. There were 156 patients included (78 cases). Complications were assessed according to the Clavien-Dindo Classification and the Comprehensive Complication Index. Continuous variables were evaluated by Student's T or Mann-Whitney tests, while categorical data were analyzed by Chi-square or Fisher tests. Univariate analyses were performed to determine discharge failure risk factors.

RESULTS

There were 6 cases (7.7%) and 5 controls (6.4%) who failed to be discharged on surgery day (P = .754), with postoperative hypoxemia (6, [3.8%]) and apnea periods (3, [1.9%]) being the most common causes. Higher BMI (odds ratio = 1.19, P = .013) and general anesthesia (odds ratio = 11.97, P = .004) were found to be risk factors for discharge failure. No difference was observed on 30-day readmissions (P = .497), unexpected visits (P = 1.000), and complications on the Clavien-Dindo Classification (P > .269) and Comprehensive Complication Index (P > .334) scales.

CONCLUSIONS

Selected patients who have SA can safely undergo outpatient hip or knee arthroplasty. Higher BMI and general anesthesia increased the odds of same-day discharge failure.

LEVEL OF EVIDENCE

Level III, Case-control Study.

Positive Airway Pressure in Surgical Patients with Sleep Apnea: What is the Supporting Evidence?

Obstructive sleep apnea (OSA) is prevalent amongst surgical patients and associated with an increased incidence of perioperative complications. The gold standard treatment for moderate-to-severe OSA is positive airway pressure (PAP) therapy. Practice guidelines by the American Society of Anesthesiologists and the Society of Anesthesia and Sleep Medicine have recommended preoperative screening for OSA and consideration of initiation of PAP therapy for patients with severe OSA. These guidelines, developed mainly by the consensus of experts, highlight the adverse impact of OSA on postoperative outcomes and recommend the use of postoperative PAP in surgical patients with moderate to severe OSA. Since the development of these guidelines, there has been an increase in the number of publications regarding the efficacy of PAP therapy in surgical patients with OSA. Our review provides an update on the existing literature on the efficacy of PAP therapy in surgical patients with OSA. We focus on the postoperative complications associated with OSA, potential mechanisms leading to the increased risk of postoperative adverse events, and summarize the perioperative guidelines for the management of patients with OSA, evidence supporting perioperative PAP therapy, as well as limitations to PAP therapy and alternatives. An update on the existing literature of the efficacy of PAP therapy in surgical patients with OSA is critical to assess the impact of prior guidelines, determine when and how to effectively implement PAP therapy, and target barriers to PAP adherence in the perioperative setting.

Increased Risk of Postoperative Complications in Patients Who Have Obstructive Sleep Apnea Undergoing Total Joint Arthroplasty: A Systematic Review and Meta-Analysis

BACKGROUND

Obstructive sleep apnea (OSA) has been linked to multiple adverse health outcomes and postoperative complications. Despite the high prevalence of OSA in patients undergoing total joint arthroplasty (TJA), few studies have evaluated the postoperative course of OSA patients after joint arthroplasty surgery.

METHODS

PubMed (MEDLINE) and Scopus (EMBASE, MEDLINE, and COMPENDEX) were used to conduct a systematic review of articles from inception to July 2023. Primary studies comparing postoperative outcomes following TJA between patients who had and did not have OSA were included. Postoperative medical complications, utilization of critical care, hospital stay, and mortality data were extracted. Descriptive statistics and random-effects meta-analysis models were used to analyze the available data. Included studies were evaluated for methodological risks of bias using the risk of bias in non-randomized studies of interventions. This review was registered on the International Prospective Register of Systematic Reviews (ID: CRD42023447610).

RESULTS

There were 7 studies with a total of 20,977 patients (9,425 hip; 11,137 knee; 415 hip or knee) that were included. Pulmonary complications were most frequently studied, followed by thromboembolic events. Cardiac, gastrointestinal, hematologic, genitourinary, and delirium events were also reported across studies. Meta-analysis revealed that OSA patients had 4-fold increased odds of overall medical complications (OR [odds ratio], 4.23; 95% confidence interval (CI), 2.97 to 6.04; P < .001; I2 = 0%), 4-fold increased odds of pulmonary complications (OR, 4.31; 95% CI, 2.82 to 6.60; P < .001; I2 = 0%), 2-fold increased odds of thromboembolic complications (OR, 1.92; 95% CI, 1.22 to 3.03; P = .005; I2 = 9%), and 4-fold increased odds of delirium (OR, 3.94; 95% CI, 1.72 to 9.04; P = .001; I2 = 0%).

CONCLUSIONS

A significant association was found between OSA and overall medical, pulmonary, and thromboembolic complications. These patients also had a higher incidence of postoperative delirium. The present findings underscore the need for comprehensive perioperative strategies to mitigate these risks in OSA patients who elect to undergo TJA.

Comorbid Factors and Selection for Same-Day Total Joint Arthroplasty

Given that the number of total joint arthroplasties (TJAs) performed worldwide is expected to continue to increase, and there are significant costs associated with these procedures, selecting candidates for same-day or 23-hour discharge is important in lowering costs and providing greater access. Younger, healthier patients are excellent candidates for same-day discharge after TJA. Preoperative medical assessment can help exclude patients who may not be candidates, such as patients with 1 or more comorbidities that increase the risk of intra- and postoperative complications and who may require a longer period of monitoring.

The impact of semi-upright position on severity of sleep disordered breathing in patients with obstructive sleep apnea: a two-arm, prospective, randomized controlled trial

BACKGROUND

The severity of sleep-disordered breathing is known to worsen postoperatively and is associated with increased cardio-pulmonary complications and increased resource implications. In the general population, the semi-upright position has been used in the management of OSA. We hypothesized that the use of a semi-upright position versus a non-elevated position will reduce postoperative worsening of OSA in patients undergoing non-cardiac surgeries.

METHODS

This study was conducted as a prospective randomized controlled trial of perioperative patients, undergoing elective non-cardiac inpatient surgeries. Patients underwent a preoperative sleep study using a portable polysomnography device. Patients with OSA (apnea hypopnea index (AHI) > 5 events/hr), underwent a sleep study on postoperative night 2 (N2) after being randomized into an intervention group (Group I): semi-upright position (30 to 45 degrees incline), or a control group (Group C) (zero degrees from horizontal). The primary outcome was postoperative AHI on N2. The secondary outcomes were obstructive apnea index (OAI), central apnea index (CAI), hypopnea index (HI), obstructive apnea hypopnea index (OAHI) and oxygenation parameters.

RESULTS

Thirty-five patients were included. Twenty-one patients were assigned to the Group 1 (females-14 (67%); mean age 65 ± 12) while there were fourteen patients in the Group C (females-5 (36%); mean age 63 ± 10). The semi-upright position resulted in a significant reduction in OAI in the intervention arm (Group C vs Group I postop AHI: 16.6 ± 19.0 vs 8.6 ± 11.2 events/hr; overall p = 0.01), but there were no significant differences in the overall AHI or other parameters between the two groups. Subgroup analysis of patients with "supine related OSA" revealed a decreasing trend in postoperative AHI with semi-upright position, but the sample size was too small to evaluate statistical significance.

CONCLUSION

In patients with newly diagnosed OSA, the semi-upright position resulted in improvement in obstructive apneas, but not the overall AHI.

TRIAL REGISTRATION

This trial was retrospectively registered in clinicaltrials.gov NCT02152202 on 02/06/2014.

Validity of non-contact methods for diagnosis of Obstructive Sleep Apnea: a systematic review and meta-analysis

STUDY OBJECTIVE

Obstructive Sleep Apnea (OSA) is associated with increased perioperative cardiac, respiratory and neurological complications. Pre-operative OSA risk assessment is currently done through screening questionnaires with high sensitivity but poor specificity. The objective of this study was to evaluate the validity and diagnostic accuracy of portable, non-contact devices in the diagnosis of OSA as compared with polysomnography.

DESIGN

This study is a systematic review of English observational cohort studies with meta-analysis and risk of bias assessment.

SETTING

Pre-operative, including in the hospital and clinic setting.

PATIENTS

Adult patients undergoing sleep apnea assessment using polysomnography and an experimental non-contact tool.

INTERVENTIONS

A novel non-contact device, which does not utilize any monitor that makes direct contact with the patient's body, in conjunction with polysomnography.

MEASUREMENTS

Primary outcomes included pooled sensitivity and specificity of the experimental device in the diagnosis of obstructive sleep apnea, in comparison to gold-standard polysomnography.

RESULTS

Twenty-eight of 4929 screened studies were included in the meta-analysis. A total of 2653 patients were included with the majority being patients referred to a sleep clinic (88.8%). Average age was 49.7(SD±6.1) years, female sex (31%), average body mass index of 29.5(SD±3.2) kg/m², average apnea-hypopnea index (AHI) of 24.7(SD±5.6) events/h, and pooled OSA prevalence of 72%. Non-contact technology used was mainly video, sound, or bio-motion analysis. Pooled sensitivity and specificity of non-contact methods in moderate to severe OSA diagnosis (AHI > 15) was 0.871 (95% CI 0.841,0.896, I² 0%) and 0.8 (95% CI 0.719,0.862), respectively (AUC 0.902). Risk of bias assessment showed an overall low risk of bias across all domains except for applicability concerns (none were conducted in the perioperative setting).

CONCLUSION

Available data indicate contactless methods have high pooled sensitivity and specificity for OSA diagnosis with moderate to high level of evidence. Future research is needed to evaluate these tools in the perioperative setting.

Sleep study measures on post-operative night one following expansion pharyngoplasty for obstructive sleep apnea

PURPOSE

To examine the changes in measures of sleep apnea severity and hypoxemia on the first post-operative night (PON1) following expansion pharyngoplasty as a means to assess the safety of same day discharge after surgery.

MATERIALS AND METHODS

Prospective cohort study of subjects with moderate-severe obstructive sleep apnea who underwent expansion pharyngoplasty at a single academic sleep surgical practice. A WatchPAT study was performed on the night immediately following surgery (PON1) and comparisons were made to baseline sleep testing.

RESULTS

Twenty subjects who had a mean age of 45.7 ± 10.8 years old and a mean body-mass index (BMI) of 31.4 ± 3.2 kg/m² were enrolled. Patients had baseline severe OSA with mean apnea hypopnea index (AHI) 39.4 ± 19.5/h, O2 nadir 80.8 ± 6.1 % and time with oxygen saturation below 88 % (T88) 12.3 ± 13.2 min. Measures of sleep apnea and nocturnal hypoxemia were not significantly different on PON1. AHI was increased by >20 % in 11 (55.0 %) patients. One patient demonstrated a >10 % worsening in O2 nadir, and 8 patients (45.0 %) demonstrated a >20 % worsening in T88. BMI over 32 was associated with elevated odds of worsening in T88, and anesthesia involving ketamine was associated with lower odds of a 20 % worsening in AHI or T88.

CONCLUSIONS

On PON1 following expansion pharyngoplasty, AHI and nocturnal hypoxemia are stable overall but variable on an individual basis. The decision for admission should therefore be made on a case-by-case basis. Further research is need to elucidate definitive predictors of worsening measures on PON1.

Perioperative trends in neck and leg fluid volume in surgical patients: a prospective observational proof-of-concept study

PURPOSE

The severity of obstructive sleep apnea (OSA) may increase postoperatively. The changes in segmental fluid volume, especially neck fluid volume, may be related to increasing airway collapsibility and thus worsening of OSA in the postoperative period. Our objective was to evaluate the feasibility of performing bioelectrical impedance analysis (BIA) and to describe the trend and predictors of changes in segmental fluid volumes in patients receiving general anesthesia for noncardiac surgery.

METHODS

We conducted a prospective observational proof-of-concept cohort study of adult patients undergoing elective inpatient noncardiac surgery. Patients underwent a portable sleep study before surgery, and segmental fluid volumes (neck fluid volume [NFV], NFV phase angle, and leg fluid volume [LFV]) were measured using BIA at set time points: preoperative period (preop), in the postanesthesia care unit (PACU), the night following surgery at 10 pm (N 0), and the following day at 10 am (POD 1). Linear regression models were constructed to evaluate for significant predictors of overall segmental fluid changes. The variables included in the models were sex, preoperative apnea-hypopnea index (AHI), fluid balance, body mass index (BMI), cumulative opioids, and the timepoint of measurement.

RESULTS

Thirty-five adult patients (20/35 females, 57%) were included. For the feasibility outcome, measure of recruitment was 50/66 (76%) and two measures of protocol adherence were fluid measurements (34/39, 87%) and preoperative sleep study (35/39, 90%). There was a significant increase in NFV from preop to N 0 and in LFV from preop to PACU. Neck fluid volume also increased from PACU to N 0 and PACU to POD 1, while LFV decreased during the same intervals. The overall changes in NFV were associated with the preop AHI, BMI, and opioids after adjusting for body position and pneumoperitoneum.

CONCLUSIONS

This proof-of-concept study showed the feasibility and variability of segmental fluid volumes in the perioperative period using BIA. We found an increase in NFV and LFV in the immediate postoperative period in both males and females, followed by the continued rise in NFV and a simultaneous decrease in LFV, which suggest the occurrence of rostral fluid shift. Preoperative AHI, BMI, and opioids predicted the NFV changes.

STUDY REGISTRATION

ClinicalTrials.gov; NCT02666781, registered 25 January 2016; NCT03850041, registered 20 February 2019.

Perioperative management of obstructive sleep apnea in lower extremity orthopedic procedures: A review of evidence to inform the development of a clinical pathway

Obstructive sleep apnea (OSA) is unrecognized in as high as 80% of patients before surgery. When untreated, OSA increases a surgical patient's propensity for airway collapse and sleep deprivation lending to a higher risk for emergent re-intubation, prolonged recovery time, escalation of care, hospital readmission, and longer length of stay. We have reviewed the evidence regarding diagnostic performance of OSA screening methods and the impact of perioperative management strategies on postoperative complications among patients with diagnosed or suspected OSA who are undergoing orthopedic surgery. We then integrated the data and recommendations from professional society guidelines to develop an evidence-based clinical care pathway to optimize the perioperative management of this surgical population. Successful management of patients with diagnosed or suspected OSA encompass five facets of care: screening, education, airway management, medications, and monitoring. This narrative review revealed two gaps in the evidence to inform management of patients undergoing orthopedic surgery 1) during the perioperative setting to include evidence-based interventions that reduce postoperative complications and 2) after discharge to an unmonitored environment. The clinical care pathway as well as perspectives for future research are discussed.

The effectiveness of positive airway pressure therapy in reducing postoperative adverse outcomes in surgical patients with obstructive sleep apnea: A systematic review and meta-analysis

IMPORTANCE

Obstructive sleep apnea (OSA) is prevalent in surgical patients and is associated with an increased risk of adverse perioperative events.

STUDY OBJECTIVE

To determine the effectiveness of positive airway pressure (PAP) therapy in reducing the risk of postoperative complications in patients with OSA undergoing surgery.

DESIGN

Systematic review and meta-analysis searching Medline and other databases from inception to October 17, 2021. The search terms included: "positive airway pressure," "surgery," "post-operative," and "obstructive sleep apnea." The inclusion criteria were: 1) adult patients with OSA undergoing surgery; (2) patients using preoperative and/or postoperative PAP; (3) at least one postoperative outcome reported; (4) control group (patients with OSA undergoing surgery without preoperative and/or postoperative PAP therapy); and (5) English language articles.

PATIENTS

Twenty-seven studies included 30,514 OSA patients undergoing non-cardiac surgery and 837 OSA patients undergoing cardiac surgery.

INTERVENTION

PAP therapy MAIN RESULTS: In patients with OSA undergoing non-cardiac surgery, PAP therapy was associated with a decreased risk of postoperative respiratory complications (2.3% vs 3.6%; RR: 0.72, 95% CI: 0.51-1.00, asymptotic P = 0.05) and unplanned ICU admission (0.12% vs 4.1%; RR: 0.44, 95% CI: 0.19-0.99, asymptotic P = 0.05). No significant differences were found for all-cause complications (11.6% vs 14.4%; RR: 0.89, 95% CI: 0.74-1.06, P = 0.18), postoperative cardiac and neurological complications, in-hospital length of stay, and in-hospital mortality between the two groups. In patients with OSA undergoing cardiac surgery, PAP therapy was associated with decreased postoperative cardiac complications (33.7% vs 50%; RR: 0.63, 95% CI: 0.51-0.77, P < 0.0001), and postoperative atrial fibrillation (40.1% vs 66.7%; RR: 0.59, 95% CI 0.45-0.77, P < 0.0001).

CONCLUSION

In patients with OSA undergoing non-cardiac surgery, PAP therapy was associated with a 28% reduction in the risk of postoperative respiratory complications and 56% reduction in unplanned ICU admission. In patients with OSA undergoing cardiac surgery, PAP therapy decreased the risk of postoperative cardiac complications and atrial fibrillation by 37% and 41%, respectively.

Validation of the STOP-Bang questionnaire as a preoperative screening tool for obstructive sleep apnea: a systematic review and meta-analysis

BACKGROUND

Obstructive sleep apnea (OSA) is a common disorder that is highly associated with postoperative complications. The STOP-Bang questionnaire is a simple screening tool for OSA. The objective of this systematic review and meta-analysis is to evaluate the validity of the STOP-Bang questionnaire for screening OSA in the surgical population cohort.

METHODS

A systematic search of the following databases was performed from 2008 to May 2021: MEDLINE, Medline-in-process, Embase, Cochrane Central Register of Controlled Trials, Cochrane Database of Systematic Reviews, PsycINFO, Journals @ Ovid, Web of Science, Scopus, and CINAHL. Continued literature surveillance was performed through October 2021.

RESULTS

The systematic search identified 4641 articles, from which 10 studies with 3247 surgical participants were included in the final analysis. The mean age was 57.3 ± 15.2 years, and the mean BMI was 32.5 ± 10.1 kg/m² with 47.4% male. The prevalence of all, moderate-to-severe, and severe OSA were 65.2, 37.7, and 17.0%, respectively. The pooled sensitivity of the STOP-Bang questionnaire for all, moderate-to-severe, and severe OSA was 85, 88, and 90%, and the pooled specificities were 47, 29, and 27%, respectively. The area under the curve for all, moderate-to-severe, and severe OSA was 0.84, 0.67, and 0.63.

CONCLUSIONS

In the preoperative setting, the STOP-Bang questionnaire is a valid screening tool to detect OSA in patients undergoing surgery, with a high sensitivity and a high discriminative power to reasonably exclude severe OSA with a negative predictive value of 93.2%.

TRIAL REGISTRATION

PROSPERO registration  CRD42021260451 .

Reduction in medical emergency team activation among postoperative surgical patients at risk for undiagnosed obstructive sleep apnea

STUDY OBJECTIVES

Obstructive sleep apnea (OSA) is an under-recognized condition that results in morbidity and mortality. Postoperative complications, including medical emergency team activation (META), are disproportionally increased among surgical patients at risk for OSA. A systematic approach is needed to improve provider recognition and treatment, but protocols that demonstrate improvement in META are lacking. As part of a multidisciplinary quality improvement project, DOISNORE50 (DIS), a sleep apnea questionnaire and proactive safety measure, was algorithmically applied to all perioperative patients.

METHODS

Consecutive sleep screening was conducted among perioperative patients. Of the 49,567 surgical navigation center patients, 11,932 had previous diagnosis of OSA. Of the 37,572 (96%) patients screened with DIS, 25,171 (66.9%) were Low Risk (DIS < 4), 9,211 (24.5%) were At Risk (DIS ≥ 4), and 3,190 (8.5%) were High Risk (DIS ≥ 6) for OSA, respectively. High Risk patients received same-day sleep consultation. On the day of surgery, patients with Known OSA, At Risk, and High Risk for OSA received an "OSA Precaution Band." An electronic chart reminder alerted admission providers to order postoperative continuous positive airway pressure (CPAP) machine and sleep consult for patients High Risk for OSA.

RESULTS

Implementation of a comprehensive program was associated with increased sleep consultation, sleep testing, and inpatient CPAP use (P < .001). For every 1,000 surgical patients screened, 30 fewer META, including rapid responses, reintubation, code blues, and code strokes, were observed. However, inpatient sleep consultation and inpatient CPAP use were not independently associated with reduced META. In the subgroup of patients hospitalized longer than 3 days, inpatient CPAP use was independently associated with reduced META.

CONCLUSIONS

In this single-center, institution-wide, multidisciplinary-approach, quality improvement project, a comprehensive OSA screening process and treatment algorithm with appropriate postoperative inpatient CPAP therapy and inpatient sleep consultations was associated with increased CPAP use and reduced META. Further prospective studies are needed to assess cost, feasibility, and generalizability of these findings.

CITATION

Namen AM, Forest D, Saha AK, et al. Reduction in medical emergency team activation among postoperative surgical patients at risk for undiagnosed obstructive sleep apnea. J Clin Sleep Med. 2022;18(8):1953-1965.

Combination therapy of high-flow nasal cannula and upper body elevation for postoperative sleep disordered breathing; randomized cross-over trial

BACKGROUND

Low acceptance rate of continuous positive airway pressure therapy in postoperative patients with untreated obstructive sleep apnea (OSA) indicates the necessity for development of an alternative postoperative airway management strategy. We considered whether the combination of high-flow nasal cannula and upper body elevation could improve postoperative OSA.

METHODS

This non-blinded randomized crossover study performed at a single university hospital investigated the effect on a modified apnea hypopnea index, based exclusively on the airflow signal without arterial oxygen saturation criteria (flow-based apnea hypopnea index, primary outcome), of high-flow nasal cannula (20 liter.minute-1 with 40% oxygen concentration) with and without upper body elevation in patients with moderate to severe OSA. Preoperative sleep studies were performed at home (control, no head-of-bed elevation) and in hospital (30-degree head-of-bed elevation). On the first and second postoperative nights, high-flow nasal cannula was applied with or without 30-degree head-of-bed elevation, assigned in random order to 23 eligible participants.

RESULTS

Twenty-two out of the 23 (96%) accepted high-flow nasal cannula. Four participants resigned from the study. Control flow-based apnea hypopnea index (mean±SD: 59.6 ± 12.0 events.hour-1, n=19) was reduced by 14.7 (95% CI: 5.5 to 30.0) events.hour-1 with head-of-bed elevation alone (p=0.002), 10.9 (1.2 to 20.6) events.hour-1 with high-flow nasal cannula alone (p=0.028), and 22.5 (13.1 to 31.9) events.hour-1 with combined head-of-bed elevation and high-flow nasal cannula (p<0.001). Compared to sole high-flow nasal cannula, additional intervention with head-of-bed elevation significantly decreased flow-based apnea hypopnea index by 11.5 events.hour-1 (1.7 to 21.4) (p=0.022). High-flow nasal cannula, alone or in combination with head-of-bed elevation also improved overnight oxygenation. No harmful events were observed.

CONCLUSION

The combination of high-flow nasal cannula and upper body elevation reduced OSA severity and nocturnal hypoxemia, suggesting a role for it as an alternate postoperative airway management strategy.

Postoperative outcomes in surgical patients with obstructive sleep apnoea diagnosed by sleep studies: a meta-analysis and trial sequential analysis

Identifying surgical patients with obstructive sleep apnoea may assist with anaesthetic management to minimise postoperative complications. Using trial sequential analysis, we evaluated the impact of obstructive sleep apnoea diagnosed by polysomnography or home sleep apnoea testing on postoperative outcomes in surgical patients. Multiple databases were systematically searched. Outcomes included: total postoperative complications, systemic complications (cardiovascular, respiratory, neurological, renal, infectious) and specific complications (atrial fibrillation, myocardial infarction, combined hospital and intensive care unit re-admission, mortality). The pooled odds ratios of postoperative complications were evaluated by the Mantel-Haenszel method random-effects model. Meta-analysis and meta-regression were conducted, and the GRADE approach was used to evaluate the certainty of evidence. Twenty prospective cohort studies with 3756 patients (2127 obstructive sleep apnoea and 1629 non-obstructive sleep apnoea) were included (9 in non-cardiac surgery and 11 in cardiac surgery). Postoperative complications were almost two-fold higher with obstructive sleep apnoea, OR (95%CI) 1.92 (1.52-2.42), p < 0.001; certainty of evidence, moderate. Obstructive sleep apnoea was associated with a 1.5 times increased risk of postoperative cardiovascular complications, OR (95%CI) 1.56 (1.20-2.02), p = 0.001; certainty of evidence, moderate; an almost two-fold increase in respiratory complications, OR (95%CI) 1.91 (1.39-2.62), p < 0.001; certainty of evidence, moderate; and hospital and ICU re-admission, OR (95%CI) 2.25 (1.21-4.19), p = 0.01; certainty of evidence, low. Trial sequential analysis showed adequate information size for postoperative complications. Baseline confounding factors were adjusted by meta-regression, and the sub-group analysis did not materially change our results. This increased risk occurred especially in patients in whom obstructive sleep apnoea had been newly diagnosed, emphasising the importance of pre-operative screening.

Polysomnography in pre-operative screening for obstructive sleep apnea in patients undergoing bariatric surgery: a retrospective cohort study

BACKGROUND/OBJECTIVES

To assess the impact of obstructive sleep apnea (OSA) screening with polysomnography on preventing cardiovascular and pulmonary complications in the postoperative period of bariatric surgery.

SUBJECTS/METHODS

This was a single-center retrospective cohort study, including 522 adults who underwent bariatric surgery between August 2010 and May 2019. Electronic medical records were accessed to obtain variables of interest. Screening for OSA was performed as a medical indication and registered as positive if apnea-hypopnea index was ≥5 events/hour in patients who did not have previous OSA diagnosis. The primary outcome was the presence of cardiac or pulmonary events in the 30-day postoperative period. Secondary outcomes included length of stay (days), need for an intensive care unit (ICU) after surgery, length of mechanical ventilation, and time from mechanical ventilation withdrawal. Statistical analyses were performed with χ², Fisher's exact test, Student's t-test, Mann-Whitney U test, and Poisson regression.

RESULTS

Most participants (n = 326) did not have OSA screening with polysomnography, while 196 had performed this screening. There was no difference in cardiopulmonary events between the screening and non-screening groups (4.2% vs. 2.8%; P = 0.45). Polysomnography screening could not reduce cardiovascular or pulmonary complications in the postoperative period, RR = 1.73 (95% CI: 0.68-4.14). There was no difference in ICU admission, length of stay, and time from mechanical ventilation between groups in secondary outcomes.

CONCLUSIONS

Our study suggests that OSA screening with polysomnography in the pre-operative care of bariatric surgery is a dispensable procedure, as it does not change postoperative cardiopulmonary outcomes. Indications for polysomnography should be made at the individual level.

The Relationship Between Postoperative Opioid Analgesia and Sleep Apnea Severity in Patients Undergoing Hip Arthroplasty: A Randomized, Controlled, Triple-Blinded Trial

PURPOSE

Residual postoperative pain after hip arthroplasty is usually treated with oral opioids. While classic opioids are associated with respiratory depression and worsening of sleep apnea, tramadol has been reported to preserve respiratory function. However, this has not been investigated in a prospective trial using respiratory polygraphy. This randomized controlled triple-blinded trial tested the hypothesis that postoperative treatment with oral opioids such as oxycodone would increase sleep apnea severity, measured with a respiratory polygraphy, compared with oral tramadol.

PATIENTS AND METHODS

Sixty patients undergoing hip arthroplasty under spinal anesthesia with 15 mg isobaric bupivacaine 0.5% were randomized to receive postoperative pain treatment with either oral oxycodone (controlled-release 10 mg every 12 hours and immediate-release 5 mg every 4 hours as needed) or oral tramadol (controlled-release 100 mg every 8 hours and immediate-release 50 mg every 4 hours as needed). Respiratory polygraphy was performed on the first postoperative night. The primary outcome was the apnea-hypopnea index in the supine position. Secondary outcomes included the oxygen desaturation index, postoperative pain scores and intravenous morphine consumption.

RESULTS

Mean supine apnea-hypopnea index on postoperative night 1 was 11.3 events.h^-1 (95% confidence interval, 4.8-17.7) in the oxycodone group and 10.7 (4.6-16.8) events.h^-1 in the tramadol group (p=0.89). There were no significant differences between the oxycodone and tramadol groups with respect to any secondary sleep-related or pain-related outcomes.

CONCLUSION

Oral oxycodone did not increase sleep apnea severity measured using respiratory polygraphy compared with oral tramadol on the first postoperative night after hip arthroplasty.

TRIAL REGISTRATION NUMBER

Clinicaltrials.gov - NCT03454217 (date of registration: 05/03/2018).

Syndromic surveillance of the frequency and severity of respiratory compromise of brachycephalic dogs in ICUs

BACKGROUND

Brachycephalic dogs (BCD) are increasingly popular companion animals and widely recognized to suffer from respiratory compromise based upon their conformation; however, the actual percentages of BCD in veterinary ICUs are unknown. This study aimed to evaluate a canine ICU census, as well as the presence, development, and severity of respiratory compromise in BCD using syndromic surveillance.

KEY FINDINGS

Ten institutions provided surveillance data twice weekly over an 11-week study period. The total canine ICU census was 1254 dogs hospitalized during the days and times of the study period; of this population, 125 (10%) were BCD. Fifty-six (45%) BCD were hospitalized in ICUs because they were perceived to be at risk of respiratory complications while recovering from general anesthesia or had a nonrespiratory condition requiring ICU admission, with the remaining 69 dogs (55%) being treated for respiratory disease. Twenty dogs (16%) developed respiratory complications requiring ICU admission after initially being hospitalized for another condition. Four percent of dogs were supported with mechanical ventilation.

CLINICAL SIGNIFICANCE

Syndromic surveillance was a useful method for evaluating the number of BCD in a veterinary ICU. Almost 1 in 5 BCD developed respiratory compromise after initial evaluation for an unrelated problem. Ongoing evaluation of the medical issues associated with brachycephaly is warranted.

Sleep Study Measures on Postoperative Night 1 Following Implantation of the Hypoglossal Nerve Stimulator

OBJECTIVE

To examine the changes in measures of sleep apnea severity and hypoxemia on the first postoperative night following implantation of the hypoglossal nerve stimulator.

STUDY DESIGN

This was a single-arm prospective cohort study.

SETTING

A single academic sleep surgical practice.

METHODS

Subjects with moderate to severe obstructive sleep apnea underwent implantation of the hypoglossal nerve stimulator (HGNS) and were discharged to home the same day as surgery. A single-night WatchPAT study was performed on the night immediately following surgery (PON 1) and was compared to baseline sleep testing.

RESULTS

Twenty subjects who were an average of 58.6 ± 2.5 years old, were 25% female, and had a mean body mass index of 28.1 ± 0.9 kg/m² completed the study. Mean O₂ nadir at baseline was 79.6% ± 1.1% compared to 82.7% ± 0.9% (P = .013) on PON 1. One patient demonstrated a >10% worsening in O₂ nadir. Only 2 additional patients demonstrated a worsening in O₂ nadir on PON 1, each by only 1 percentage point. Neither mean time spent below SpO₂ 88% nor oxygen desaturation index (ODI) worsened postoperatively (mean time spent below oxygen saturation of 88%, 27.8 ± 7.85 vs 11.2 ± 5.2, P = .03; mean ODI, 29.6 ± 5.2/h vs 21.0 ± 5.4/h, P = .10). Mean obstructive apnea hypopnea index (AHI) was no worse (40.6 ± 4.7/h to 28.7 ± 4.2/h, P = .02), with only 2 patients experiencing an obstructive AHI >20% more severe than baseline. Only 1 patient demonstrated a clinically meaningful increase in central AHI on PON 1.

CONCLUSIONS

Overall, AHI and measures of nocturnal hypoxemia are stable, if not improved, on PON 1 following HGNS implantation. These findings support the safety of same-day discharge following implantation of the hypoglossal nerve stimulator.

Case-Ascertainment Models to Identify Adults with Obstructive Sleep Apnea Using Health Administrative Data: Internal and External Validation

Background

There is limited evidence on whether obstructive sleep apnea (OSA) can be accurately identified using health administrative data.

Study Design and Methods

We derived and validated a case-ascertainment model to identify OSA using linked provincial health administrative and clinical data from all consecutive adults who underwent a diagnostic sleep study (index date) at two large academic centers (Ontario, Canada) from 2007 to 2017. The presence of moderate/severe OSA (an apnea–hypopnea index≥15) was defined using clinical data. Of 39 candidate health administrative variables considered, 32 were tested. We used classification and regression tree (CART) methods to identify the most parsimonious models via cost-complexity pruning. Identified variables were also used to create parsimonious logistic regression models. All individuals with an estimated probability of 0.5 or greater using the predictive models were classified as having OSA.

Results

The case-ascertainment models were derived and validated internally through bootstrapping on 5099 individuals from one center (33% moderate/severe OSA) and validated externally on 13,486 adults from the other (45% moderate/severe OSA). On the external cohort, parsimonious models demonstrated c-statistics of 0.75–0.81, sensitivities of 59–60%, specificities of 87–88%, positive predictive values of 79%, negative predictive values of 73%, positive likelihood ratios (+LRs) of 4.5–5.0 and –LRs of 0.5. Logistic models performed better than CART models (mean integrated calibration indices of 0.02–0.03 and 0.06–0.12, respectively). The best model included: sex, age, and hypertension at the index date, as well as an outpatient specialty physician visit for OSA, a repeated sleep study, and a positive airway pressure treatment claim within 1 year since the index date.

Interpretation

Among adults who underwent a sleep study, case-ascertainment models for identifying moderate/severe OSA using health administrative data had relatively low sensitivity but high specificity and good discriminative ability. These findings could help study trends and outcomes of OSA individuals using routinely collected health care data.

Increased Suicidality and Worse Outcomes in MDD Patients With OSA: A Nationwide Inpatient Analysis of 11 Years From 2006 to 2017

BACKGROUND

Major depressive disorder (MDD) is the most common psychiatric disorder characterized by changes in mood, cognition, and physical symptoms. MDD has an approximate 18% prevalence of comorbid OSA. Several studies have looked into plausible mechanisms that have shown a strong relationship between OSA and MDD.

OBJECTIVES

The primary objective of this study was to compare suicidal ideation/attempt among MDD patients with and without a comorbid diagnosis of OSA. The secondary objective was to compare the length of stay, total hospital charge, recurrent or severity of depression, and clinical comorbidities.

METHODS

Data were obtained from the National (Nationwide) Inpatient Sample dataset from 2006 to 2017. For data collection, we queried for all adult patients (age ≥ 18 y), with MDD as a primary indication of admission. Further, we categorized MDD patients with and without a secondary diagnosis of OSA. To reduce the imbalance in baseline characteristics between the groups, we performed one to one age-gender matching between MDD patients with and without OSA.

RESULTS

In the matched cohort, 79,308 patients were included in MDD with OSA and 78,792 patients in the MDD without OSA group. MDD patients with OSA were more likely to be racially white (80% vs 75%, P < 0.001), and to have more clinical comorbidities (hypertension, heart failure, obesity, and chronic lung disease). Prevalence of recurrent type of depression (77% vs 69%, P < 0.001) and moderate to severe depression (72% vs 68%, P < 0.001) was more likely in the MDD with OSA group. Further, suicidality (composite of suicidal ideation/attempt) was more in MDD with OSA (49.5%) compared to MDD without OSA (41.8%) (P < 0.001). In the multivariate analysis, MDD with OSA was associated with higher odds of suicidal ideation/act compared to MDD without OSA (adjusted odds ratio: 1.27, P < 0.001). The total length of stay was longer in the MDD with OSA group (7.4 vs 6.9 d, P < 0.001).

CONCLUSIONS

In our study, poorer outcomes were observed in patients with MDD and OSA. Hence, clinicians should be vigilant for symptoms of OSA in patients with recurrent MDD or treatment-resistant MDD. We recommend that a thorough suicide risk assessment should be conducted in MDD patients with OSA, and validated questionnaires should be a part of the evaluation.

Trends in Comorbidities and Complications Among Patients Undergoing Hip Fracture Repair

BACKGROUND

Hip fracture patients represent various perioperative challenges related to their significant comorbidity burden and the high incidence of morbidity and mortality. As population trend data remain rare, we aimed to investigate nationwide trends in the United States in patient demographics and outcomes in patients after hip fracture repair surgery.

METHODS

After Institutional Review Board (IRB) approval (IRB#2012-050), data covering hip fracture repair surgeries were extracted from the Premier Healthcare Database (2006-2016). Patient demographics, comorbidities, and complications, as well as anesthesia and surgical details, were analyzed over time. Cochran-Armitage trend tests and simple linear regression assessed significance of (linear) trends.

RESULTS

Among N = 507,274 hip fracture cases, we observed significant increases in the incidence in preexisting comorbid conditions, particularly the proportion of patients with >3 comorbid conditions (33.9% to 43.4%, respectively; P < .0001). The greatest increase for individual comorbidities was seen for sleep apnea, drug abuse, weight loss, and obesity. Regarding complications, increased rates over time were seen for acute renal failure (from 6.9 to 11.1 per 1000 inpatient days; P < .0001), while significant decreasing trends for mortality, pneumonia, hemorrhage/hematoma, and acute myocardial infarction were recorded. In addition, decreasing trends were observed for the use of neuraxial anesthesia either used as sole anesthetic or combined with general anesthesia (7.3% to 3.6% and 6.3% to 3.4%, respectively; P < .0001). Significantly more patients (31.9% vs 41.3%; P < .0001) were operated on in small rather than medium- and large-sized hospitals.

CONCLUSIONS

From 2006 to 2016, the overall comorbidity burden increased among patients undergoing hip fracture repair surgery. Throughout this same time period, incidence of postoperative complications either remained constant or declined with the only significant increase observed in acute renal failure. Moreover, use of regional anesthesia decreased over time. This more comorbid patient population represents an increasing burden on the health care system; however, existing preventative measures appear to be effective in minimizing complication rates. Although, given the proposed benefits of regional anesthesia, decreased utilization may be of concern.

Cost Analysis of Medicare Patients with Varying Complexities Who Underwent Total Knee Arthroplasty

The effort to reduce overall healthcare costs may affect more complex patients, as their pre- and postoperative care can be substantially involved. Therefore, the purpose of this study was to use a large nationwide insurance database to compare (1) costs, (2) reimbursements, and (3) net losses of 90-day episodes of care (EOC) for total knee arthroplasty (TKA) patients according to Elixhauser's Comorbidity Index (ECI) scores. All TKAs performed between 2005 and 2014 in the Medicare Standard Analytic Files were extracted from the database and stratified based on ECI scores, ranging from 1 to 5. ECI 1 patients served as the control cohort, while ECI 2, 3, 4, and 5 patients were considered study cohorts. Each study cohort and control cohort were matched based on age and sex, resulting in a total of 715,398 patients included for analysis. Total EOC costs, reimbursements, and total net losses (defined as total EOC costs minus total EOC reimbursements) were compared between the cohorts. Overall, total EOC costs increased with ECI. For example, compared with the matched ECI 1 cohorts, the total EOC costs for ECI 5 patients ($56,589.19 vs. $51,747.54) were significantly greater (p < 0.01). Although reimbursements increased with increasing ECI, so did net losses. The net losses for ECI 5 patients were greater than that for ECI 1 patients ($42,309.39 vs. $40,007.82). The bundled payments for care improvement (BPCI) and comprehensive care for joint replacement (CJR) are alternative payment models that might de-incentivize treatment of more complex patients. Our study found that despite increasing reimbursements, overall costs, and therefore net losses, were greater for more complex patients with higher ECI scores.

Post-operative outcomes and anesthesia type in total hip arthroplasty in patients with obstructive sleep apnea: A retrospective analysis of the State Inpatient Databases

STUDY OBJECTIVES

To investigate postoperative outcomes following total hip arthroplasty (THA) in patients with obstructive sleep apnea (OSA). To evaluate trends in the use of regional anesthesia (RA) versus general anesthesia (GA) following the publication of practical guidelines. To compare postoperative outcomes according to anesthesia type.

DESIGN

Retrospective analysis.

SETTING

Operating room.

PATIENTS

349,008 patients who underwent elective THA in Florida, New York, Maryland, and Kentucky between 2007 and 2014 were extracted from the State Inpatient Databases (SID), Healthcare Cost and Utilization Project, including 18,063 patients with OSA (5.2%).

INTERVENTIONS

No intervention.

MEASUREMENTS

The effect of OSA on postoperative outcomes was investigated using bivariate analysis and multivariable logistic regression models. Outcomes studied included in-hospital mortality, postoperative complications, length of stay (LOS), and post-discharge readmissions. In a population from New York only, (n = 105,838 with 5306 patients with OSA [5.0%]), we investigated the outcomes in the OSA population according to the anesthesia type. Analysis was performed overall and for each individual year.

MAIN RESULTS

The OSA prevalence increased from 1.7% in 2007 to 7.1% in 2014. In multivariable analysis, there was no effect of OSA on in-hospital mortality (aOR:0.57; 0.31-1.04). Postoperative complications, LOS, and readmission rates were all higher in patients with OSA. In patients with OSA receiving GA than those receiving RA, we found a higher rate of complications overall and pulmonary complications specifically in men and higher rate of 90-day readmission in women. Over the study period, the rate of GA use in patients with OSA increased.

CONCLUSIONS

The OSA prevalence in patients undergoing THA increased fourfold over the study period. OSA was associated with increased overall postoperative complications, LOS, and readmission, but not with in-hospital mortality. Despite the publication of guidelines favoring RA over GA, the use of GA increased over the study period.

Perioperative Care and Medication-related Hypoventilation

Cumulative evidence supports the association of adverse postoperative outcomes with obstructive sleep apnea (OSA) and obesity hypoventilation syndrome (OHS). Although current guidelines recommend preoperative screening for OSA and OHS, the best perioperative management pathways remain unknown. Interventions attempting to prevent complications in the postoperative period largely are consensus based and focused on enhanced monitoring, conservative measures, and specific OSA therapies, such as positive airway pressure. Until further research is available to improve the quality and strength of these recommendations, patients with known or suspected OSA and OHS should be considered at higher risk for perioperative cardiopulmonary complications.

Predicting CPAP failure in patients with suspected sleep hypoventilation identified on ambulatory testing

STUDY OBJECTIVES

Home sleep apnea testing (HSAT) is commonly used to diagnose obstructive sleep apnea, but its role in identifying patients with suspected hypoventilation or predicting their response to continuous positive airway pressure (CPAP) therapy has not been assessed. The primary objective was to determine if HSAT, combined with clinical variables, could predict the failure of CPAP to correct nocturnal hypoxemia during polysomnography in a population with suspected hypoventilation. Secondary objectives were to determine if HSAT and clinical parameters could predict awake or sleep hypoventilation.

METHODS

A retrospective review was performed of 142 consecutive patients who underwent split-night polysomnography for suspected hypoventilation after clinical assessment by a sleep physician and review of HSAT. We collected quantitative indices of nocturnal hypoxemia, patient demographics, medications, pulmonary function tests, as well as arterial blood gas data from the night of the polysomnography . CPAP failure was defined as persistent obstructive sleep apnea, hypoxemia (oxygen saturation measured by pulse oximetry < 85%), or hypercapnia despite maximal CPAP.

RESULTS

Failure of CPAP was predicted by awake oxygen saturation and arterial blood gas results but not by HSAT indices of nocturnal hypoxemia. Awake oxygen saturation ≥ 94% ruled out CPAP failure, and partial pressure of oxygen measured by arterial blood gas ≥ 68 mmHg decreased the likelihood of CPAP failure significantly.

CONCLUSIONS

In patients with suspected hypoventilation based on clinical review and HSAT interpretation by a sleep physician, awake oxygen saturation measured by pulse oximetry and partial pressure of oxygen measured by arterial blood gas can reliably identify patients in whom CPAP is likely to fail. Additional research is required to determine the role of HSAT in the identification and treatment of patients with hypoventilation.

Impact of short-acting vs. standard anaesthetic agents on obstructive sleep apnoea: a randomised, controlled, triple-blind trial

Sleep apnoea is associated with negative outcomes following general anaesthesia. Current recommendations suggest using short‐acting anaesthetic agents in preference to standard agents to reduce this risk, but there is currently no evidence to support this. This randomised controlled triple‐blind trial tested the hypothesis that a combination of short‐acting agents (desflurane‐remifentanil) would reduce the postoperative impact of general anaesthesia on sleep apnoea severity compared with standard agents (sevoflurane‐fentanyl). Sixty patients undergoing hip arthroplasty under general anaesthesia were randomised to anaesthesia with desflurane‐remifentanil or sevoflurane‐fentanyl. Respiratory polygraphy was performed before surgery and on the first and third postoperative nights. The primary outcome was the supine apnoea‐hypopnoea index on the first postoperative night. Secondary outcomes were the supine apnoea‐hypopnoea index on the third postoperative night, and the oxygen desaturation index on the first and third postoperative nights. Additional outcomes included intravenous morphine equivalent consumption and pain scores on postoperative days 1, 2 and 3. Pre‐operative sleep study data were similar between groups. Mean (95%CI) values for the supine apnoea‐hypopnoea index on the first postoperative night were 18.9 (12.7–25.0) and 21.4 (14.2–28.7) events.h⁻¹, respectively, in the short‐acting and standard anaesthesia groups (p = 0.64). Corresponding values on the third postoperative night were 28.1 (15.8–40.3) and 38.0 (18.3–57.6) events.h⁻¹ (p = 0.34). Secondary sleep‐ and pain‐related outcomes were generally similar in the two groups. In conclusion, short‐acting anaesthetic agents did not reduce the impact of general anaesthesia on sleep apnoea severity compared with standard agents. These data should prompt an update of current recommendations.

Cost-effectiveness Analysis of Preoperative Screening Strategies for Obstructive Sleep Apnea among Patients Undergoing Elective Inpatient Surgery

Background

Obstructive sleep apnea is underdiagnosed in surgical patients. The cost-effectiveness of obstructive sleep apnea screening is unknown. This study’s objective was to evaluate the cost-effectiveness of preoperative obstructive sleep apnea screening (1) perioperatively and (2) including patients’ remaining lifespans.

Methods

An individual-level Markov model was constructed to simulate the perioperative period and lifespan of patients undergoing inpatient elective surgery. Costs (2016 Canadian dollars) were calculated from the hospital perspective in a single-payer health system. Remaining model parameters were derived from a structured literature search. Candidate strategies included: (1) no screening; (2) STOP-Bang questionnaire alone; (3) STOP-Bang followed by polysomnography (STOP-Bang + polysomnography); and (4) STOP-Bang followed by portable monitor (STOP-Bang + portable monitor). Screen-positive patients (based on STOP-Bang cutoff of at least 3) received postoperative treatment modifications and expedited definitive testing. Effectiveness was expressed as quality-adjusted life month in the perioperative analyses and quality-adjusted life years in the lifetime analyses. The primary outcome was the incremental cost-effectiveness ratio.

Results

In perioperative and lifetime analyses, no screening was least costly and least effective. STOP-Bang + polysomnography was the most effective strategy and was more cost-effective than both STOP-Bang + portable monitor and STOP-Bang alone in both analyses. In perioperative analyses, STOP-Bang + polysomnography was not cost-effective compared to no screening at the $4,167/quality-adjusted life month threshold (incremental cost-effectiveness ratio $52,888/quality-adjusted life month). No screening was favored in more than 90% of iterations in probabilistic sensitivity analyses. In contrast, in lifetime analyses, STOP-Bang + polysomnography was favored compared to no screening at the $50,000/quality-adjusted life year threshold (incremental cost-effectiveness ratio $2,044/quality-adjusted life year). STOP-Bang + polysomnography was favored in most iterations at thresholds above $2,000/quality-adjusted life year in probabilistic sensitivity analyses.

Conclusions

The cost-effectiveness of preoperative obstructive sleep apnea screening differs depending on time horizon. Preoperative screening with STOP-Bang followed by immediate confirmatory testing with polysomnography is cost-effective on the lifetime horizon but not the perioperative horizon. The integration of preoperative screening based on STOP-Bang and polysomnography is a cost-effective means of mitigating the long-term disease burden of obstructive sleep apnea.

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Intrathecal Morphine and Pulmonary Complications after Arthroplasty in Patients with Obstructive Sleep Apnea

Background

Intrathecal morphine is commonly and effectively used for analgesia after joint arthroplasty, but has been associated with delayed respiratory depression. Patients with obstructive sleep apnea may be at higher risk of postoperative pulmonary complications. However, data is limited regarding the safety of intrathecal morphine in this population undergoing arthroplasty.

Methods

This retrospective cohort study aimed to determine the safety of intrathecal morphine in 1,326 patients with documented or suspected obstructive sleep apnea undergoing hip or knee arthroplasty. Chart review was performed to determine clinical characteristics, perioperative events, and postoperative outcomes. All patients received neuraxial anesthesia with low-dose (100 μg) intrathecal morphine (exposure) or without opioids (control). The primary outcome was any postoperative pulmonary complication including: (1) respiratory depression requiring naloxone; (2) pneumonia; (3) acute respiratory event requiring consultation with the critical care response team; (4) respiratory failure requiring intubation/mechanical ventilation; (5) unplanned admission to the intensive care unit for respiratory support; and (6) death from a respiratory cause. The authors hypothesized that intrathecal morphine would be associated with increased postoperative complications.

Results

In 1,326 patients, 1,042 (78.6%) received intrathecal morphine. The mean age of patients was 65 ± 9 yr and body mass index was 34.7 ± 7.0 kg/m2. Of 1,326 patients, 622 (46.9%) had suspected obstructive sleep apnea (Snoring, Tired, Observed, Pressure, Body Mass Index, Age, Neck size, Gender [STOP-Bang] score greater than 3), while 704 of 1,326 (53.1%) had documented polysomnographic diagnosis. Postoperatively, 20 of 1,322 (1.5%) patients experienced pulmonary complications, including 14 of 1,039 (1.3%) in the exposed and 6 of 283 (2.1%) in the control group (P = 0.345). Overall, there were 6 of 1 322 (0.5%) cases of respiratory depression, 18 of 1,322 (1.4%) respiratory events requiring critical care team consultation, and 4 of 1,322 (0.3%) unplanned intensive care unit admissions; these rates were similar between both groups. After adjustment for confounding, intrathecal morphine was not significantly associated with postoperative pulmonary complication (adjusted odds ratio, 0.60 [95% CI, 0.24 to 1.67]; P = 0.308).

Conclusions

Low-dose intrathecal morphine, in conjunction with multimodal analgesia, was not reliably associated with postoperative pulmonary complications in patients with obstructive sleep apnea undergoing joint arthroplasty.

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Postoperative Outcomes of Patients With Obstructive Sleep Apnea Undergoing Cardiac Surgery

BACKGROUND

Obstructive sleep apnea (OSA) is associated with increased risk of postoperative complications in noncardiac surgery, with limited literature on cardiac surgical patients. Perioperative outcomes of patients with OSA were compared with outcomes of those without OSA undergoing cardiac surgery.

METHODS

This was a retrospective single-center cohort study of adults who underwent cardiac surgery from January 2010 to April 2017. Outcomes of patients with OSA were compared with those without OSA, including length of stay, readmissions, hospital death, and short-term outcomes.

RESULTS

OSA was present in 2636 of 8612 patients (30.6%) identified during the study period with OSA. Patients with OSA had a longer median length of stay (6 vs 5 days, P < .001), longer incidence of prolonged (>7 days) length of stay (26.3% vs 23.0%, P < .001), and were less likely to be discharged to home (78.2% vs 84.4%, P < .001). OSA patients also had a higher 30-day readmission rate (14.7% vs 10.4%, P < .001). Acute kidney injury was more common in OSA patients (25.2% vs 19.9%, P < .001). Our multivariable model found postoperative atrial fibrillation was associated with older age and not OSA status (age <50 years compared with >75 years; odds ratio, 4.10; 95% confidence interval, 3.39-4.96).

CONCLUSIONS

OSA patients had a longer mean length of stay, were more likely to have a prolonged length of stay, more likely to be discharged to a location other than home, and had a higher 30-day readmission rate. This suggests higher resource utilization is required to care for OSA patients after cardiac surgery.

Outcomes and Safety Among Patients With Obstructive Sleep Apnea Undergoing Cancer Surgery Procedures in a Freestanding Ambulatory Surgical Facility

BACKGROUND

Patients with obstructive sleep apnea (OSA) may be at increased risk for serious perioperative complications. The suitability of ambulatory surgery for patients with OSA remains controversial, and several national guidelines call for more evidence that assesses clinically significant outcomes. In this study, we investigate the association between OSA status (STOP-BANG risk, or previously diagnosed) and short-term outcomes and safety for patients undergoing cancer surgery at a freestanding ambulatory surgery facility.

METHODS

We conducted a retrospective analysis of all patients having surgery at the Josie Robertson Surgery Center, a freestanding ambulatory surgery facility of the Memorial Sloan Kettering Cancer Center. Surgeries included more complex ambulatory extended recovery procedures for which patients typically stay overnight, such as mastectomy, thyroidectomy, and minimally invasive hysterectomy, prostatectomy, and nephrectomy, as well as typical outpatient surgeries. Both univariate and multivariable analyses were used to assess the association between OSA risk and transfer to the main hospital, urgent care center visit, and hospital readmission within 30 days postoperatively (primary outcomes) and length of stay and discharge time (secondary outcomes). Multivariable models were adjusted for age, American Society of Anesthesiologists score, robotic surgery, and type of anesthesia (general or monitored anesthesia care) and also adjusted for surgery start time for length of stay and discharge time outcomes. χ tests were used to assess the association between OSA risk and respiratory events and device use.

RESULTS

Of the 5721 patients included in the analysis, 526 (9.2%) were diagnosed or at moderate or high risk for OSA. We found no evidence of a difference in length of stay when comparing high-risk or diagnosed patients with OSA to low- or moderate-risk patients whether they underwent outpatient (P = .2) or ambulatory extended recovery procedures (P = .3). Though a greater frequency of postoperative respiratory events were reported in high-risk or diagnosed patients with OSA compared to moderate risk (P = .004), the rate of hospital transfer was not significantly different between the groups (risk difference, 0.78%; 95% CI, -0.43% to 2%; P = .2). On multivariable analysis, there was no evidence of increased rate of urgent care center visits (adjusted risk difference, 1.4%; 95% CI, -0.68% to 3.4%; P = .15) or readmissions within 30 days (adjusted risk difference, 1.2%; 95% CI, -0.40% to 2.8%; P = .077) when comparing high-risk or diagnosed OSA to low- or moderate-risk patients. Based on the upper bounds of the CIs, a clinically relevant increase in transfers, readmissions, and urgent care center visits is unlikely.

CONCLUSIONS

Our results contribute to the body of evidence supporting that patients with moderate-risk, high-risk, or diagnosed OSA can safely undergo outpatient and advanced ambulatory oncology surgery without increased health care burden of extended stay or hospital admission and avoiding adverse postoperative outcomes. Our results support the adoption of several national OSA guidelines focusing on preoperative identification of patients with OSA and clinical pathways for perioperative management and postoperative monitoring.

Point-of-Care Ultrasound for Obstructive Sleep Apnea Screening: Are We There Yet? A Systematic Review and Meta-analysis

BACKGROUND

Perioperative diagnosis of obstructive sleep apnea (OSA) has important resource implications as screening questionnaires are overly sensitive, and sleep studies are expensive and time-consuming. Ultrasound (US) is a portable, noninvasive tool potentially useful for airway evaluation and OSA screening in the perioperative period. The objective of this systematic review was to evaluate the correlation of surface US with OSA diagnosis and to determine whether a point-of-care ultrasound (PoCUS) for OSA screening may help with improved screening in perioperative period.

METHODS

A search of all electronic databases including Medline, Embase, and Cochrane Database of Systematic Reviews was conducted from database inception to September 2017. Inclusion criteria were observational cohort studies and randomized controlled trials of known or suspected OSA patients undergoing surface US assessment. Article screening, data extraction, and summarization were conducted by 2 independent reviewers with ability to resolve conflict with supervising authors. Diagnostic properties and association between US parameters (index test) and OSA diagnosis using sleep study (reference standard) were evaluated. The US parameters were divided into airway and nonairway parameters. A random-effects meta-analysis was planned, wherever applicable.

RESULTS

Of the initial 3865 screened articles, 21 studies (7 airway and 14 nonairway) evaluating 3339 patients were included. Majority of studies were conducted in the general population (49%), respirology (23%), and sleep clinics (12%). No study evaluated the use of US for OSA in perioperative setting. Majority of included studies had low risk of bias for reference standard and flow and timing. Airway US parameters having moderate-good correlation with moderate-severe OSA were distance between lingual arteries (DLAs > 30 mm; sensitivity, 0.67; specificity, 0.59; 1 study/66 patients); mean resting tongue thickness (>60 mm; sensitivity, 0.85; specificity, 0.59; 1 study/66 patients); tongue base thickness during Muller maneuver (MM; sensitivity, 0.59; specificity, 0.78; 1 study/66 patients); and a combination of neck circumference and retropalatal (RP) diameter shortening during MM (sensitivity, 1.0; specificity, 0.65; 1 study/104 patients). Nonairway US parameters having a low-moderate correlation with moderate-severe OSA were carotid intimal thickness (pooled correlation coefficient, 0.444; 95% confidence interval [CI], 0.320-0.553; P value = .000, 8 studies/727 patients) and plaque presence (sensitivity, 0.24-0.75; specificity, 0.13-1.0; 4 studies/1183 patients).

CONCLUSIONS

We found that a number of airway and nonairway parameters were identified with moderate to good correlation with OSA diagnosis in the general population. In future studies, it remains to be seen whether PoCUS screening for a combination of these parameters can address the pitfalls of OSA screening questionnaires.

Implementation Science: Incorporating Obstructive Sleep Apnea Screening and Capnography Into Everyday Practice

PURPOSE

This article describes the implementation and maintenance of obstructive sleep apnea (OSA) screening and capnography monitoring.

DESIGN

A quality improvement project.

METHODS

A multidisciplinary team provided staff education to three perianesthesia care units. Using the STOP-Bang screening tool, five or more positive responses indicated high risk for OSA. A postanesthesia care unit audit tool tracked STOP-Bang scores, capnography use, hypoventilation events, nursing interventions, and respiratory complications.

FINDINGS

Among 314 patients with OSA, 36% were identified as high risk. Nurses used capnography on 76% of OSA patients and were able to readily identify hypoventilation and intervene. Respiratory complications occurred in 10.8% (n = 34) requiring a higher level of care. Postimplementation, all six postanesthesia care units employ this best practice.

CONCLUSIONS

Perianesthesia nurses found OSA screening and capnography easy to incorporate into nursing practice. This process can reduce respiratory complications in the surgical patient with OSA. An Evidence-Based Practice Fellowship Program facilitated this practice change.

Factors associated with hospital stay length, discharge destination, and 30-day readmission rate after primary hip or knee arthroplasty: Retrospective Cohort Study

BACKGROUND

In France and in the US, predictions for 2030 include an increased number of total hip arthroplasty (THA) and total knee arthroplasty (TKA) procedures together with an overall trend towards shorter hospital stays. Predictors of hospital length of stay (LOS) include the day of surgery, discharge destination, and patient comorbidities. Available data are conflicting, however, and to our knowledge predictors of LOS after THA or TKA have not been evaluated in France. Improved knowledge of these predictors would be expected to increase patient care efficiency. The objectives of this study were: (1) to determine whether the above-listed factors predict LOS after THA or TKA, (2) to identify predictors of discharge to a rehabilitation unit and of readmission within 30 days after surgery.

HYPOTHESIS

Both patient-related factors unamenable to modification and modifiable organisational factors are associated with LOS after THA or TKA.

MATERIAL AND METHODS

This large single-centre retrospective cohort study included all adults who underwent primary THA or TKA at our university hospital between 1 January 2015 and 31 December 2016. Non-inclusion criteria were revision arthroplasty, THA with femoral or acetabular reconstruction, TKA using a constrained hinged implant, and fracture as the reason for arthroplasty. Preoperative parameters, type of arthroplasty, and postoperative care were recorded.

RESULTS

We included 938 patients with THA and 725 patients with TKA. By multivariate analysis, the likelihood of being discharged by day 5 decreased with older age (HR, 0.986; 95%CI: 0.98-0.99) and was lower by 13% in females (HR, 0,871; 95%CI: 0.77-0.986), by 39% in patients with diabetes (HR, 0.606; 95%CI: 0.5-0.73), by 68% in patients discharged to rehabilitation units (HR, 0.322; 95%CI: 0.267-0.389), and by 27% in patients who had arthroplasty on a Friday (HR, 0.733; 95%CI: 0.631-0.852). Factors predicting discharge to rehabilitation unit were older age, female gender, chronic obstructive pulmonary disease, anxiety-depressive disorder, and a history of stroke. Risk factors for 30-day readmission were male gender, obesity, and discharge to rehabilitation unit.

DISCUSSION

In this study, predictors of LOS were identified using a survival model that considered age as a continuous variable, separate comorbidities, and the discharge destination. Our findings are consistent with earlier reports and confirm the strong associations linking LOS to diabetes, day of surgery, and discharge destination in France. We also identified predictors of discharge to rehabilitation and of readmission within 30 days.

LEVEL OF EVIDENCE

IV, retrospective observational cohort study.

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.

Effects of Opioids Given to Facilitate Mechanical Ventilation on Sleep Apnea After Extubation in the Intensive Care Unit

Study Objectives

Following extubation in the intensive care unit (ICU), upper airway (UA) edema and respiratory depressants may promote UA dysfunction. We tested the hypothesis that opioids increase the risk of sleep apnea early after extubation.

Methods

Fifty-six ICU patients underwent polysomnography the night after extubation. Airflow limitation during wakefulness was identified using bedside spirometry. Correlation and ordinal regression analyses were used to quantify the effects of preextubation opioid dose on postextubation apnea-hypopnea index (AHI) and severity of sleep apnea and whether or not inspiratory airway obstruction (ratio of maximum expiratory and inspiratory airflows at 50% of vital capacity [MEF50/MIF50] ≥ 1) during wakefulness predicts airway obstruction during sleep. Data were adjusted for age, gender, body mass index, as well as a generalized propensity score balanced for APACHE II, score for preoperative prediction of obstructive sleep apnea, duration of mechanical ventilation, chronic obstructive pulmonary disease, and a procedural severity score for morbidity.

Results

Sleep apnea (AHI ≥ 5) was present in 40 (71%) of the 56 patients. Morphine equivalent dose given 24 hours prior extubation predicted obstructive respiratory events during sleep (r = 0.35, p = .01) and sleep apnea (odds ratio [OR] 1.17; 95% confidence interval [CI] 1.02-1.34). Signs of inspiratory UA obstruction (MEF50/MIF50 ≥ 1) assessed by bedside spirometry were strongly associated with sleep apnea (OR 5.93; 95% CI 1.16-30.33).

Conclusions

High opioid dose given 24 hours prior to extubation increases the likelihood of postextubation sleep apnea in the ICU, particularly in patients with anatomical vulnerability following extubation.