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

Critical evaluation of screening questionnaires for obstructive sleep apnea in patients undergoing coronary artery bypass grafting and abdominal surgery

BACKGROUND

Obstructive sleep apnea (OSA) is an independent risk factor for complications after surgery. However, OSA remains largely under recognized, and questionnaires designed to detect OSA have shown inconsistent results. Patients with cardiovascular diseases may not present with the typical symptoms of OSA. We therefore sought to compare the performance of screening questionnaires of patients referred for coronary artery bypass grafting (CABG) versus abdominal surgery (Abd surgery).

METHODS

We studied 40 consecutive patients referred for CABG [29 men; age 56 ± 7 years; body mass index (BMI) 30 ± 4 kg/m(2)], and 41 referred to Abd Surgery matched for age, gender, and BMI (28 men; age 56 ± 8 years; BMI 29 ± 5 kg/m(2)). All patients were evaluated with validated questionnaires to predict OSA (STOP-Bang and Berlin), Epworth sleepiness scale (ESS) and full overnight polysomnography.

RESULTS

The prevalence of OSA (apnea-hypopnea index ≥15 events/hour) in the CABG and Abd surgery groups was similar (52 and 41 %, respectively, p = 0.32). The Berlin questionnaire showed similar sensitivity (67 vs. 82 %, p = 0.17) but lower specificity in the CABG group (26 vs. 62 %, p = 0.02). The STOP-BANG questionnaire had a high sensitivity (90 vs. 94 %, p = 0.42) but low specificity (5 vs. 13 %, p = 0.25) in the CABG and Abd surgery groups, respectively. Patients referred for CABG slept less (323 [285-376] vs. 378 [308-415] minutes, p = 0.04) but had lower levels of daytime sleepiness than Abd surgery patients had (ESS, 6 ± 4 vs. 9 ± 5; p = 0.01, respectively).

CONCLUSIONS

Presenting clinical characteristics of OSA are modulated by the population evaluated and may affect the performance of screening questionnaires.

Can a validated sleep apnea scoring system predict cardiopulmonary events using propofol sedation for routine EGD or colonoscopy? A prospective cohort study

BACKGROUND

Obstructive sleep apnea (OSA), which is linked to the prevalence of obesity, continues to rise in the United States. There are limited data on the risk for sedation-related adverse events (SRAE) in patients with undiagnosed OSA receiving propofol for routine EGD and colonoscopy.

OBJECTIVE

To identify the prevalence of OSA by using the STOP-BANG questionnaire (SB) and subsequent risk factors for airway interventions (AI) and SRAE in patients undergoing elective EGD and colonoscopy.

DESIGN

Prospective cohort study.

SETTING

Tertiary-care teaching hospital.

PATIENTS

A total of 243 patients undergoing routine EGD or colonoscopy at Cleveland Clinic.

INTERVENTION

Chin lift, mask ventilation, placement of nasopharyngeal airway, bag mask ventilation, unplanned endotracheal intubation, hypoxia, hypotension, or early procedure termination.

MAIN OUTCOME MEASUREMENTS

Rates of AI and SRAE.

RESULTS

Mean age of the cohort was 50 ± 16.2 years, and 41% were male. The prevalence of SB+ was 48.1%. The rates of hypoxia (11.2% vs 16.9%; P = .20) and hypotension (10.4% vs 5.9%; P = .21) were similar between SB- and SB+ patients. An SB score ≥3 was found not to be associated with occurrence of AI (relative risk [RR] 1.07, 95% confidence interval [CI] 0.79-1.5) or SRAE (RR 0.81, 95% CI, 0.53-1.2) after we adjusted for total and loading dose of propofol, body mass index (BMI), smoking, and age. Higher BMI was associated with an increased risk for AI (RR 1.02; 95% CI, 1.01-1.04) and SRAE (RR 1.03; 95% CI, 1.01-1.05). Increased patient age (RR 1.09; 95% CI, 1.02-1.2), higher loading propofol doses (RR 1.4; 95% CI, 1.1-1.8), and smoking (RR 1.9; 95% CI, 1.3-2.9) were associated with higher rates of SRAE.

LIMITATIONS

Non-randomized study.

CONCLUSION

A significant number of patients undergoing routine EGD and colonoscopy are at risk for OSA. SB+ patients are not at higher risk for AI or SRAE. However, other risk factors for AI and SRAE have been identified and must be taken into account to optimize patient safety.

Transversus abdominis plane infiltration for laparoscopic gastric banding: A pilot study

AIM: To estimate an effect size for the transversus abdominis plane (TAP) infiltration on quality of recovery in patients undergoing laparoscopic gastric band surgery.

METHODS: The pilot study was a randomized, double blinded, placebo controlled trial. Patients undergoing laparoscopic gastric band surgery were randomized to receive a bilateral TAP infiltration with 20 mL of 0.5% ropivacaine or saline. The evaluated outcomes included quality of recovery-40 (QoR-40) at 24 h, postoperative opioid consumption and pain. Data was examined using the Mann-Whitney U test.

RESULTS: Nineteen subjects were recruited. There was a positive trend favoring the TAP infiltration group in global QoR-40 scores at 24 h after surgery, median [interquartile range (IQR)] of 175.5 (170-189) compared to 170 (160-175) in the control group (P = 0.06). There also a positive trend toward a lower cumulative opioid consumption in the TAP infiltration group, median (IQR) of 7.5 (2.5-11.5) mg iv morphine equivalents compared to 13 (7-21.5) in the control group (P = 0.07). Correlation analysis (Spearman’s Rho) demonstrated an inverse relationship between 24 h cumulative opioid consumption and global QoR-40 scores, -0.49 (P = 0.03).

CONCLUSION: The use of multimodal analgesic techniques to reduce opioid related side effects is particularly desirable in morbidly obese patients undergoing gastric reduction surgery. The TAP infiltration seems to have a clinically important effect in reducing postoperative opioid consumption and improve quality of recovery after laparoscopic gastric band surgery in morbid obese patients. Future studies to confirm the beneficial effects of the TAP infiltration in these patients are warranted.

Factors Associated with Postoperative Exacerbation of Sleep-disordered Breathing

Introduction:

The knowledge on the mechanism of the postoperative exacerbation of sleep-disordered breathing may direct the perioperative management of patients with obstructive sleep apnea. The objective of this study is to investigate the factors associated with postoperative severity of sleep-disordered breathing.

Methods:

After obtaining approvals from Institutional Review Boards, consenting patients underwent portable polysomnography preoperatively, and on postoperative nights 1 and 3 in hospital or at home. The primary outcomes were polysomnography parameters measuring the sleep-disordered breathing. They were treated as repeated measurement variables and analyzed for associated factors by mixed models.

Results:

Three hundred seventy-six patients, 168 men and 208 women, completed polysomnography on preoperative and postoperative night 1. Age was 59 ± 12 yr (mean ± SD). Preoperative apnea–hypopnea index (AHI) was 12 (4, 26) (median [25th, 75th percentile]) events per hour. Thirty-five patients had minor surgeries, 292 intermediate surgeries, and 49 major surgeries, with 210 general anesthesia and 166 regional anesthesia. The 72-h opioid dose was 55 (14, 85) mg intravenous morphine-equivalent dose. Preoperative AHI, age, and 72-h opioid dose were associated with postoperative AHI. Preoperative central apnea index, male sex, and general anesthesia were associated with postoperative central apnea index. Slow wave sleep percentage was inversely associated with postoperative AHI and central apnea index.

Conclusions:

Patients with a higher preoperative AHI were predicted to have a higher postoperative AHI. Preoperative AHI, age, and 72-h opioid dose were positively associated with postoperative AHI. Preoperative central apnea, male sex, and general anesthesia were associated with postoperative central apnea index.

Emerging risk factors and prevention of perioperative pulmonary complications

Modern surgery is faced with the emergence of newer "risk factors" and the challenges associated with identifying and managing these risks in the perioperative period. Obstructive sleep apnea and obesity hypoventilation syndrome pose unique challenges in the perioperative setting. Recent studies have identified some of the specific risks arising from caring for such patients in the surgical setting. While all possible postoperative complications are not yet fully established or understood, the prevention and management of these complications pose even greater challenges. Pulmonary hypertension with its changing epidemiology and novel management strategies is another new disease for the surgeon and the anesthesiologist in the noncardiac surgical setting. Traditionally most such patients were not considered surgical candidates for any required elective surgery. Our review discusses these disease entities which are often undiagnosed before elective noncardiac surgery.

Obstructive Sleep Apnea and Surgery: Quality Improvement Imperatives and Opportunities

Obstructive sleep apnea (OSA) is more common in surgical candidates than in the general population and may increase susceptibility to perioperative complications that range from transient desaturation to catastrophic injuries. Understanding the potential impact of OSA on patients' surgical risk profile is of particular interest to otolaryngologists, who routinely perform airway procedures-including surgical procedures for treatment of OSA. Whereas the effects of OSA on long-term health outcomes are well documented, the relationship between OSA and surgical risk is not collinear, and clear consensus on the nature of the association is lacking. Better guidelines for optimization of pain control, perioperative monitoring, and surgical decision making are potential areas for quality improvement efforts. Many interventions have been suggested to mitigate the risk of adverse events in surgical patients with OSA, but wide variations in clinical practice remain. We review the current literature, emphasizing recent progress in understanding the complex pathophysiologic interactions noted in OSA patients undergoing surgery and outlining potential strategies to decrease perioperative risks.

Postoperative vascular complications in unrecognised Obstructive Sleep apnoea (POSA) study protocol: an observational cohort study in moderate-to-high risk patients undergoing non-cardiac surgery

INTRODUCTION

Emerging epidemiological data suggest that obstructive sleep apnoea (OSA) is common in the general surgical population. Unfortunately, the majority of these patients are unrecognised and untreated at the time of surgery. There is substantial biological rationale to indicate that patients with unrecognised OSA are at a higher risk of postoperative vascular events. However, the extent of this morbidity is currently unknown. We have initated the postoperative vascular complications in the unrecognised obstructive sleep apnoea (POSA) study to determine the associations between OSA, nocturnal hypoxia and major postoperative vascular events in 1200 moderate-to-high risk patients undergoing major non-cardiac surgery.

METHODS AND ANALYSIS

The POSA study is an international prospective observational cohort study. Using a type 3 portable sleep monitoring device and ambulatory oximetry, we will quantify the severity of OSA. The primary outcome is a composite of vascular death, myocardial infarction; non-fatal cardiac arrest; stroke; pulmonary embolism; congestive heart failure and new arrhythmia within 30 days of surgery. As of November 2013, we have recruited over 700 patients from nine centres in six countries. The mean age is 68 years, the mean body mass index is 27 kg/m(2) and 55% of patients are men. 27.9% of patients have known coronary artery disease, over 76% have diabetes. The majority of patients underwent orthopaedic surgery (28%) and colorectal resection (18.5%).

ETHICS AND DISSEMINATION

The POSA study has received ethics approval from all study sites before patient recruitment. Informed consent will be obtained from all patients. The POSA study will determine the risk of unrecognised OSA in major non-cardiac surgery. We will publish these findings in peer-reviewed journals.

TRIAL REGISTRATION

ClinicalTrials.gov Identifier: NCT01494181.

Sleep-disordered breathing and postoperative outcomes after elective surgery: analysis of the nationwide inpatient sample

BACKGROUND

Systematic screening and treatment of sleep-disordered breathing (SDB) or obstructive sleep apnea (OSA) in presurgical patients would impose a significant cost burden; therefore, it is important to understand whether SDB is associated with worse postoperative outcomes. We sought to determine the impact of SDB on postoperative outcomes in patients undergoing four specific categories of elective surgery (orthopedic, prostate, abdominal, and cardiovascular). The primary outcomes were in-hospital death, total charges, and length of stay (LOS). Two secondary outcomes of interest were respiratory and cardiac complications.

METHODS

Data were obtained from the Nationwide Inpatient Sample database. Regression models were fitted to assess the independent association between SDB and the outcomes of interest.

RESULTS

The cohort included 1,058,710 hospitalized adult patients undergoing elective surgeries between 2004 and 2008. SDB was independently associated with decreased mortality in the orthopedic (OR, 0.65; 95% CI, 0.45-0.95; P = .03), abdominal (OR, 0.38; 95% CI, 0.22-0.65; P = .001), and cardiovascular surgery groups (OR, 0.54; 95% CI, 0.40-0.73; P < .001) but had no impact on mortality in the prostate surgery group. SDB was independently associated with a small, but statistically significant increase in estimated mean LOS by 0.14 days (P < .001) and estimated mean total charges by $860 (P < .001) in the orthopedic surgery group but was not associated with increased LOS or total charges in the prostate surgery group. In the abdominal and cardiovascular surgery groups, SDB was associated with a significant decrease in adjusted mean LOS of 1.1 days and 0.35 days, respectively (P < .001 for both groups), and adjusted mean total charges of $3,814 and $4,592, respectively (P < .001 for both groups). SDB was independently associated with a significantly increased OR for emergent intubation and mechanical ventilation, noninvasive ventilation, and atrial fibrillation in all four surgical categories. Emergent intubation occurred significantly earlier in the postoperative course in patients with SDB. In the subgroup of patients requiring emergent intubation, LOS, total charges, pneumonias, and in-hospital death were significantly higher in those without SDB.

CONCLUSIONS

In this large national study, despite the increased independent association of SDB with postoperative cardiopulmonary complications, the diagnosis of SDB was not independently associated with an increased rate of in-hospital death. SDB had a mixed impact on LOS and total charges by surgical category.

Obstructive sleep apnea in general surgery patients: is it more common than we think?

BACKGROUND

To determine the risk of obstructive sleep apnea (OSA) in preoperative surgical patients.

METHODS

Three hundred seventy-one new patients presenting to an outpatient general surgery clinic were prospectively screened for risk of OSA using the STOP-Bang questionnaire. Patients were classified as high risk with a score of >3 on the STOP-Bang questionnaire. Polysomnography results were reviewed when available.

RESULTS

Complete questionnaires were available on 367 (98.9%) patients. Two hundred thirty-seven patients (64.6%) were classified as high risk of OSA on the questionnaire. Polysomnography results available on 49 patients revealed severe OSA in 17 (34.5%), moderate in 8 (16.5%), mild in 14 (28.5%), and no OSA in 10 (20.5%) patients. The positive predictive value and sensitivity of the questionnaire were 76%, and 92% for the STOP-Bang questionnaire, respectively. The sensitivity increased to 100% for severe OSA.

CONCLUSION

Preoperative screening for OSA should be considered to diagnose patients at risk.

Obstructive sleep apnea as a risk factor after shoulder arthroplasty

BACKGROUND

Obstructive sleep apnea (OSA) has been identified as an important risk factor in perioperative orthopaedic surgery outcomes despite limited evidence. Screening systems are being instituted in increasing frequency to prevent morbidity and mortality. Our objective was to determine if patients with OSA have a higher likelihood of postoperative in-hospital complications, length of stay, or increased costs after shoulder arthroplasty.

METHODS

We utilized the Nationwide Inpatient Sample (NIS) to analyze 22988 patients undergoing TSA or hemiarthroplasty. Of these patients, 1983 (5.9%) were diagnosed with OSA. Multivariate analysis with logistic regression modeling was used to compare patients with and without OSA for various outcomes.

RESULTS

Patients with obstructive sleep apnea had overall similar in-hospital mortality and complications including PE compared with those without OSA. OSA was not associated with increased postoperative charges ($39,741 in patients with OSA vs. $39,334 in those without OSA) and resulted in a shorter length of stay (mean, 2.61 vs. 2.91 days; P < .0001).

CONCLUSION

This study does not support OSA as a significant risk factor for in-hospital morbidity and mortality following shoulder arthroplasty. Our results suggest that a diagnosis of OSA does not increase perioperative morbidity and mortality including perioperative complications. Given the results of this study, further research is warranted to attempt to keep patient screening costs down while optimizing outcomes.

Nonventilatory strategies to prevent postoperative pulmonary complications

PURPOSE OF REVIEW

In this review, we aimed at providing the most recent and relevant clinical evidence regarding the use of nonventilatory strategies to prevent postoperative pulmonary complications (PPCs) after noncardiac surgery.

RECENT FINDINGS

Although nonavoidable, most comorbidities can be modified in order to reduce the incidence of pulmonary events postoperatively. The physical status of patients suffering from chronic obstructive pulmonary disease, asthma, obstructive sleep apnea, and congestive heart failure can be improved preoperatively, and a number of measures can be undertaken to prevent PPCs, including physiotherapy for pulmonary rehabilitation and drug therapies. Also, smokers may benefit from both short and long-term smoke cessation. Furthermore, the risk of PPCs may be reduced upon: choice of an adequate anesthesia strategy (e.g. regional vs. general); appropriate neuromuscular blockade and reversal; use of volatile instead of intravenous anesthetics in lung surgery; judicious intravascular volume expansion (restrictive vs. liberal strategy); regional instead of systemic analgesia after major surgery in high-risk patients; more strict indication for nasogastric decompression in order to avoid silent aspiration; and laparoscopic instead of open bariatric surgery.

SUMMARY

Nonventilatory strategies can play an important role in reducing PPCs and improving clinical outcome after noncardiac surgery, especially in high-risk patients.

The association of pre-operative STOP-BANG scores with postoperative critical care admission

The STOP-BANG questionnaire screens for obstructive sleep apnoea. We retrospectively analysed the independent association of pre-operative variables with postoperative critical care admission using multivariable logistic regression for patients undergoing elective surgery from January to December 2011. Of 5432 patients, 338 (6.2%) were admitted postoperatively to the critical care unit. In multivariate analysis, the odds ratios (95% CI) for critical care admission were: 2.2 (1.1-4.6), p = 0.037; 3.2 (1.2-8.1), p = 0.017; and 5.1 (1.8-14.9), p = 0.002, for STOP-BANG scores of 4, 5 and ≥ 6, respectively. The odds ratio was also independently increased for: each year of age, 1.015 (1.004-1.026), p = 0.019; asthma, 1.6 (1.1-2.4), p = 0.016; obstructive sleep apnoea, 3.2 (1.9-5.6), p < 0.001; and for ASA physical status 2, 3 and ≥ 4, 2.1 (1.4-3.3), 6.5 (3.9-11.0), 6.3 (2.9-13.8), respectively, p < 0.001 for all.

Society of anesthesia and sleep medicine: proceedings of 2012 annual meeting

INTRODUCTION

We present the proceedings of the second annual meeting of the Society of Anesthesia and Sleep Medicine. The theme of the meeting was "Anesthesia and Sleep Medicine: What Every Health Professional Needs to Know."

DISCUSSION

While upper airway obstruction during sleep and anesthesia received concentrated attention, with particular regard to perioperative assessment and managment of obstuctive sleep apnea, a diversity of issues were raised including: the genetic basis for variations in ventilatory control; shared charactertics of sleep and anesthesia; hazards posed by narcotic use in patients with obstructive sleep apnea (OSA); the respiratory complication that follow surgery in such patients; who amongst them is suitable for ambulatory surgery; and the special circumstances that apply to anesthesia for children with OSA. How principles based on these considerations have been applied to protocol development at two major centers was presented towards the end of the meeting. The proceedings highlight issues discussed by each of the invited speakers but do not include the research abstracts discussed during the poster session.

Delirium after cardiac surgery: have we overlooked obstructive sleep apnea?

Obstructive sleep apnea is common in patients with cardiovascular disease. It is well known that cardiac surgery is a risk factor for delirium. Researchers have shown that obstructive sleep apnea is an independent risk factor for the occurrence of delirium. In this manuscript we speculate on how obstructive sleep apnea may increase the risk of delirium in patients with cardiac surgery. If this is found to be confirmed, we would have another target through which we can decrease the risk of delirium in this population.