Mahesh Nagappa

Validation of the STOP-Bang Questionnaire as a Screening Tool for Obstructive Sleep Apnea among Different Populations: A Systematic Review and Meta-Analysis

Background Diagnosing obstructive sleep apnea (OSA) is clinically relevant because untreated OSA has been associated with increased morbidity and mortality. The STOP-Bang questionnaire is a validated screening tool for OSA. We conducted a systematic review and meta-analysis to determine the effectiveness of STOP-Bang for screening patients suspected of having OSA and to predict its accuracy in determining the severity of OSA in the different populations. Methods A search of the literature databases was performed. Inclusion criteria were: 1) Studies that used STOP-Bang questionnaire as a screening tool for OSA in adult subjects (>18 years); 2) The accuracy of the STOP-Bang questionnaire was validated by polysomnography—the gold standard for diagnosing OSA; 3) OSA was clearly defined as apnea/hypopnea index (AHI) or respiratory disturbance index (RDI) ≥ 5; 4) Publications in the English language. The quality of the studies were explicitly described and coded according to the Cochrane Methods group on the screening and diagnostic tests. Results Seventeen studies including 9,206 patients met criteria for the systematic review. In the sleep clinic population, the sensitivity was 90%, 94% and 96% to detect any OSA (AHI ≥ 5), moderate-to-severe OSA (AHI ≥15), and severe OSA (AHI ≥30) respectively. The corresponding NPV was 46%, 75% and 90%. A similar trend was found in the surgical population. In the sleep clinic population, the probability of severe OSA with a STOP-Bang score of 3 was 25%. With a stepwise increase of the STOP-Bang score to 4, 5, 6 and 7/8, the probability rose proportionally to 35%, 45%, 55% and 75%, respectively. In the surgical population, the probability of severe OSA with a STOP-Bang score of 3 was 15%. With a stepwise increase of the STOP-Bang score to 4, 5, 6 and 7/8, the probability increased to 25%, 35%, 45% and 65%, respectively. Conclusion This meta-analysis confirms the high performance of the STOP-Bang questionnaire in the sleep clinic and surgical population for screening of OSA. The higher the STOP-Bang score, the greater is the probability of moderate-to-severe OSA.

Society of Anesthesia and Sleep Medicine Guidelines on Preoperative Screening and Assessment of Adult Patients with Obstructive Sleep Apnea

The purpose of the Society of Anesthesia and Sleep Medicine guideline on preoperative screening and assessment of adult patients with obstructive sleep apnea (OSA) is to present recommendations based on the available clinical evidence on the topic where possible. As very few well-performed randomized studies in this field of perioperative care are available, most of the recommendations were developed by experts in the field through consensus processes involving utilization of evidence grading to indicate the level of evidence upon which recommendations were based. This guideline may not be appropriate for all clinical situations and all patients. The decision whether to follow these recommendations must be made by a responsible physician on an individual basis. Protocols should be developed by individual institutions taking into account the patients’ conditions, extent of interventions and available resources. This practice guideline is not intended to define standards of care or represent absolute requirements for patient care. The adherence to these guidelines cannot in any way guarantee successful outcomes and is rather meant to help individuals and institutions formulate plans to better deal with the challenges posed by perioperative patients with OSA. These recommendations reflect the current state of knowledge and its interpretation by a group of experts in the field at the time of publication. While these guidelines will be periodically updated, new information that becomes available between updates should be taken into account. Deviations in practice from guidelines may be justifiable and such deviations should not be interpreted as a basis for claims of negligence.

The effects of continuous positive airway pressure on postoperative outcomes in obstructive sleep apnea patients undergoing surgery: A systematic review and meta-analysis

BACKGROUND:Obstructive sleep apnea (OSA) is a commonly encountered comorbid condition in patients undergoing surgery and is associated with a greater risk of postoperative adverse events. Our objective in this review was to investigate the effectiveness of continuous positive airway pressure (CPAP) in reducing the risk of postoperative adverse events in patients with OSA undergoing surgery, the perioperative Apnea-Hypopnea Index (AHI), and the hospital length of stay (LOS). METHODS:We performed a systematic search of the literature databases. We reviewed the studies that included the following: (1) adult surgical patients (>18 years old) with information available on OSA; (2) patients using either preoperative and/or postoperative CPAP or no-CPAP; (3) available reports on postoperative adverse events, preoperative and postoperative AHI, and LOS; and (4) all published studies in English including case series. RESULTS:Six studies that included 904 patients were eligible for the meta-analysis. The meta-analysis for postoperative adverse events was performed in 904 patients (CPAP: n = 471 vs no-CPAP: n = 433; adverse events: 134 vs 133; P = 0.19). There was no significant difference in the postoperative adverse events between the 2 groups. The preoperative baseline AHI without CPAP was reduced significantly with postoperative use of CPAP (preoperative AHI versus postoperative AHI, 37 ± 19 vs 12 ± 16 events per hour, P < 0.001). LOS showed a trend toward significance in the CPAP group versus the no-CPAP group (4.0 ± 4 vs 4.4 ± 8 days, P = 0.05). CONCLUSIONS:Our review suggests that there was no significant difference in the postoperative adverse events between CPAP and no-CPAP treatment. Patients using CPAP had significantly lower postoperative AHI and a trend toward shorter LOS. There may be potential benefits in the use of CPAP during the perioperative period.

CPAP in the Perioperative Setting: Evidence of Support

OSA is a commonly encountered comorbid condition in surgical patients. The risk of cardiopulmonary complications is increased by two to threefold with OSA. Among the different treatment options for OSA, CPAP is an efficacious modality. This review examines the evidence regarding the use of CPAP in the preoperative and postoperative periods in surgical patients with diagnosed and undiagnosed OSA.

Effect of preoperative and postoperative incentive spirometry on lung functions after laparoscopic cholecystectomy.

This study was designed to compare the effects of preoperative and postoperative incentive spirometry on lung functions after laparoscopic cholecystectomy in 50 otherwise normal healthy adults. Patients were randomized into a control group (group PO, n=25) and a study group (group PR, n=25). Patients in group PR were instructed to carry out incentive spirometry before the surgery 15 times, every fourth hourly, for 1 week whereas in group PO, incentive spirometry was carried out during the postoperative period. Lung functions were recorded at the time of preanesthetic evaluation, on the day before the surgery, postoperatively at 6, 24, and 48 hours, and at discharge. Significant improvement in the lung functions was seen after preoperative incentive spirometry (group PR), P<0.05. The lung functions were significantly reduced till the time of discharge in both the groups. However, lung functions were better preserved in group PR at all times when compared with group PO; P<0.05. To conclude, lung functions are better preserved with preoperative than postoperative incentive spirometry.

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

Purpose of review The present review aims to provide an update on the various practical applications of the STOP-Bang questionnaire in anesthesia, surgery, and perioperative medicine. Recent findings The STOP-Bang questionnaire was originally validated as a screening tool to identify surgical patients who are at high-risk of obstructive sleep apnea (OSA). A recent meta-analysis confirmed that STOP-Bang is validated for use in the sleep clinic, surgical, and general population. Patients with a STOP-Bang score of 0--2 can be classified as low-risk for moderate-to-severe OSA. Those with a score of 5--8 can be classified as high-risk for moderate-to-severe OSA. In patients with a score of 3 or 4, a specific combination of a STOP score at least 2 + BMI more than 35 kg/m2 or STOP score at least 2 + male or STOP score at least 2 + neck circumference more than 40 cm indicates higher risk for moderate-to-severe OSA. Further, patients with a STOP-Bang score at least 3 can be classified as high risk for moderate-to-severe OSA if the serum HCO3- at least 28 mmol/l. STOP-Bang can be used as a novel tool for perioperative risk stratification because it easily identifies patients who are at increased risk of perioperative complications. Summary STOP-Bang at least 3 was recommended previously to identify the suspected or undiagnosed OSA. To reduce the false positive cases and to improve its specificity, a stepwise stratification is recommended to identify the patients at high risk of moderate-to-severe OSA. Because of its practical application, STOP-Bang is a useful screening tool for patients with suspected or undiagnosed OSA.

Association of Stop-bang Questionnaire as a Screening Tool for Sleep Apnea and Postoperative Complications: A Systematic Review and Bayesian Meta-analysis of Prospective and Retrospective Cohort Studies

BACKGROUND: The risk of postoperative complications increases with undiagnosed obstructive sleep apnea (OSA). The high-risk OSA (HR-OSA) patients can be easily identified using the STOP-Bang screening tool. The aim of this systematic review and meta-analysis is to determine the association of postoperative complications in patients screened as HR-OSA versus low-risk OSA (LR-OSA). METHODS: The following data bases were searched from January 1, 2008, to October 31, 2016, to identify the eligible articles: Cochrane Central Register of Controlled Trials, MEDLINE, PubMed, Cochrane Databases of Systematic Reviews, Medline-in-Process & other nonindexed citations, Google Scholar, Embase, Web of Sciences and Scopus. The search included studies with adult surgical patients screened for OSA with STOP-Bang questionnaire that reported at least 1 cardiopulmonary or any other complication requiring intensive care unit admission as diagnosis of outcome. We used a Bayesian random-effects analysis to evaluate the existing evidence of STOP-Bang in relation to OSA and to assess the association of postoperative complications with the identified HR-OSA patients by study design and methodologies. RESULTS: This systematic review and meta-analysis was conducted using 10 cohort studies: 23,609 patients (HR-OSA, 7877; LR-OSA, 15,732). The pooled odds of perioperative complications were higher in the HR-OSA versus LR-OSA patients (odds ratio 3.93, 95% credible interval, 1.85–7.77, P= .003; 6.86% vs 4.62%). The length of hospital stay was longer in HR-OSA by 2 days when compared with LR-OSA (5.0 ± 4.2 vs 3.4 ± 2.8 days; mean difference 2.01; 95% credible interval, 0.77–3.24; P= .005). Meta-regression to adjust for baseline confounding factors and subgroup analysis did not materially change the results. CONCLUSIONS: This systematic review and meta-analysis suggests that HR-OSA is related with higher risk of postoperative adverse events and longer length of hospital stay when compared with LR-OSA patients. Our findings support the implementation of the STOP-Bang screening tool for perioperative risk stratification.

Diagnosis and treatment of obstructive sleep apnea during pregnancy.

Purpose of review This review aims to provide an update on recent advances in the diagnosis and treatment of obstructive sleep apnea (OSA) during pregnancy and its effect on maternal and fetal outcomes. Recent findings Current OSA screening tools may not perform well in this population. There are some pieces of evidence linking poorer maternal and neonatal outcome with pregnant patients having OSA. At present, there are inadequate data on which to base fetal or maternal parameters for treatment of OSA, and no evidence that treatment in the short-term impacts maternal or neonatal outcomes. Summary Further research is needed to help in the detection and treatment of OSA in pregnancy.

Cardiorespiratory effects of balancing PEEP with intra-abdominal pressures during laparoscopic cholecystectomy.

Background: Applying appropriate positive end-expiratory pressure (PEEP) to corresponding intra-abdominal pressure (IAP) can improve gas exchange during capnoperitoneum without any hemodynamic effects. Materials and Methods: A total of 75 patients were randomly allocated to group 0PEEP (n=25), group 5PEEP (n=25), and group 10PEEP (n=25) according to the level of PEEP, in whom capnoperitoneum was created with IAP of 14, 8, and 14 mm Hg, respectively. Hemodynamic and respiratory parameters were recorded up to 30 minutes after capnoperitoneum. Results: In 0PEEP group, mean end-tidal carbon dioxide demonstrated significant rise 2 minutes after capnoperitoneum and plateaued at about 15 minutes but remained at high level for up to 30 minutes when compared with the 5PEEP and 10PEEP groups (P<0.05). Correspondingly, the mean PaCO2 (48.0±4.1 mm Hg) for the 0PEEP group was higher at 30 minutes when compared with 5PEEP (37.8±2.7 mm Hg) and 10PEEP (37.2±3.9 mm Hg) groups. The oxygenation was better preserved in 5PEEP and 10PEEP groups with significantly higher PaO2/Fio2 ratio. Heart rate, mean arterial pressure, and cardiac output remained stable throughout the study in all the 3 groups. Conclusions: Application of appropriate PEEP corresponding to the IAP helped maintain CO2 elimination and improved oxygenation without any hemodynamic disturbance in patients undergoing laparoscopic cholecystectomy.

Death or near-death in patients with obstructive sleep apnoea: a compendium of case reports of critical complications

The care of surgical patients with obstructive sleep apnoea (OSA) invokes concerns with safety and liability because of the risk that exists for perioperative death or near-death. The purpose of this review is to analyse the available literature to identify risk factors for perioperative critical complications in patients with OSA. Literature reports were screened for life threatening complications and deaths in surgical patients with OSA. The critical complications were sub-grouped as death/near-death events (death and anoxic brain damage) vs critical respiratory events (CRE)/other events and analysed for various risk factors. Both univariate and multivariate analyses were conducted to identify the potential risk factors.In total, 15 case reports and two medico-legal reports, comprising of 60 total patients with OSA were included in our analysis. Overall, there were 43 deaths or near-death events and 12 critical respiratory events and five other life threatening events. Ten patients (17%) with OSA were undiagnosed before surgery. Only 31% (11/35) were on preoperative continuous positive airway pressure (CPAP), with 36% (4/11) of them continuing CPAP in the postoperative period. The majority of them received a morphine equivalent daily dose less than 10 mg. Eighty percent of the events occurred in the first 24 h and 67% occurred on the general hospital ward.Patients with OSA are at risk of critical complications including death during the initial 24 h after surgery. Morbid obesity, male sex, undiagnosed OSA, partially treated/untreated OSA, opioids, sedatives, and lack of monitoring are risk factors for death or near-death events.