Obstructive sleep apnoea and perioperative complications in bariatric patients

Identifying Risk of Postoperative Cardiorespiratory Complications in OSA

BACKGROUND

Patients with OSA are at increased risk of postoperative cardiorespiratory complications and death. Attempts to stratify this risk have been inadequate, and predictors from large, well-characterized cohort studies are needed.

RESEARCH QUESTION

What is the relationship between OSA severity, defined by various polysomnography-derived metrics, and risk of postoperative cardiorespiratory complications or death, and which metrics best identify such risk?

STUDY DESIGN AND METHODS

In this cohort study, 6,770 consecutive patients who underwent diagnostic polysomnography for possible OSA and a procedure involving general anesthesia within a period of 2 years before and at least 5 years after polysomnography. Participants were identified by linking polysomnography and health databases. Relationships between OSA severity measures and the composite primary outcome of cardiorespiratory complications or death within 30 days of hospital discharge were investigated using univariable and multivariable analyses.

RESULTS

The primary outcome was observed in 5.3% (n = 361) of the cohort. Although univariable analysis showed strong dose-response relationships between this outcome and multiple OSA severity measures, multivariable analysis showed its independent predictors were: age older than 65 years (OR, 2.67 [95% CI, 2.03-3.52]; P < .0001), age 55.1 to 65 years (OR, 1.47 [95% CI, 1.09-1.98]; P = .0111), time between polysomnography and procedure of ≥ 5 years (OR, 1.32 [95% CI, 1.02-1.70]; P = .0331), BMI of ≥ 35 kg/m2 (OR, 1.43 [95% CI, 1.13-1.82]; P = .0032), presence of known cardiorespiratory risk factor (OR, 1.63 [95% CI, 1.29-2.06]; P < .0001), > 4.7% of sleep time at an oxygen saturation measured by pulse oximetry of < 90% (T90; OR, 1.91 [95% CI, 1.51-2.42]; P < .0001), and cardiothoracic procedures (OR, 7.95 [95% CI, 5.71-11.08]; P < .0001). For noncardiothoracic procedures, age, BMI, presence of known cardiorespiratory risk factor, and percentage of sleep time at an oxygen saturation of < 90% remained the significant predictors, and a risk score based on their ORs was predictive of outcome (area under receiver operating characteristic curve, 0.7 [95% CI, 0.64-0.75]).

INTERPRETATION

These findings provide a basis for better identifying high-risk patients with OSA and determining appropriate postoperative care.

Complications and predictors associated with moderate to severe obstructive sleep apnoea in bariatric surgery: Evaluation of routine obstructive sleep apnoea screening

PURPOSE

Obstructive sleep apnoea (OSA) is a breathing disorder resulting in blockage of airflow and hypo-oxygenation. The incidence of OSA in patients with class 2 or 3 obesity (Body Mass index, BMI >35) is 60-70%. Unfortunately, most bariatric patients are unaware they suffer from OSA. Untreated OSA can lead to perioperative cardiopulmonary complications. The aim of this study was to identify predictors associated with moderate to severe OSA and asses the incidence of OSA-related complications in a large cohort of patients who underwent OSA-screening and treatment if indicated before bariatric surgery.

METHODS

All consecutive patients who underwent primary bariatric surgery between September 2013 and September 2019 were included. Univariable and multivariable logistic regression analysis was performed to identify potential predictors for moderate to severe OSA using sleep studies.

RESULTS

A total of 2872 patients who underwent bariatric surgery were included for analysis. Overall, OSA was identified in 62.5% of all patients and moderate to severe OSA (AHI ≥15) in 28.6%. Independent predictors for moderate to severe OSA were male gender (p < 0.001), age (p < 0.001), preoperative BMI (p < 0.001), preoperative waist circumference (p < 0.001), hypertension (p < 0.001), and dyslipidaemia (p = 0.046). The incidence of OSA-related complications was low (0.8%) and not significantly different among the different OSA severity classes.

CONCLUSION

This is the largest study to assess OSA presence and OSA-related complications in patients undergoing bariatric surgery. The incidence of potential OSA-related complications was low (0.8%). We believe focus could be shifted towards more cost-efficient strategies where OSA screening is omitted such as perioperative continuous monitoring.

Anesthesia for Morbidly Obese Patients

BACKGROUND

The prevalence of morbid obesity (BMI >35 kg/m2) has risen steadily in recent decades. With the corresponding rise in the number of bariatric operations, anesthesiologists deal with this patient group more commonly than before, particularly in specialized centers.

METHODS

This review is based on publications retrieved by a selective search in PubMed, including current guidelines and recommendations issued by specialist societies, as well as expert opinion.

RESULTS

In the anesthesiological care of morbidly obese patients, a preoperative assessment and risk stratification are just as important as the thoughtful selection of the anesthesia technique, the drugs used and their dosage, and perioperative management. A thorough understanding of the pathophysiological changes and comorbidities of morbid obesity and the associated risks is essential. The risk of pulmonary complications such as respiratory failure, hypoxia, and apnea is markedly higher in morbidly obese patients, especially those with obstructive sleep apnea. Short-acting, less lipophilic anesthetic drugs are particularly useful, as is multimodal pain therapy for the avoidance of high opiate doses. The indication for intensified postoperative monitoring depends on the patient's preexisting illnesses, the type of anesthesia, and the type of surgical procedure. Regional anesthetic techniques should be used if possible.

CONCLUSION

The perioperative care of morbidly obese patients presents special challenges. The anesthesiologist must be aware of potential comorbidities, specific risks, and pathophysiological changes in order to provide adequate care to this patient group.

Peri- and Postoperative Outcomes for Obstructive Sleep Apnoea Patients after Bariatric Surgery-a Systematic Review and Meta-analysis

BACKGROUND

Obstructive sleep apnoea (OSA) is prevalent among patients undergoing bariatric surgery. Previous studies have reported a higher risk of complications, ICU admission and longer length of stay in patients with OSA following surgery. However, clinical outcomes following bariatric surgery are unclear. The hypothesis is that patients with OSA will have an increased risk of these outcome measures after bariatric surgery.

METHODS

A systematic review and meta-analysis were performed to answer the research question. Searches for bariatric surgery and obstructive sleep apnoea were performed using PubMed and Ovid Medline. Studies which compared OSA and non-OSA patients undergoing bariatric surgery and used outcome measures that included length of stay, risk of complications, 30-day readmission and need for ICU admission were selected for the systematic review. Comparable datasets from these studies were used for the meta-analysis.

RESULTS

Patients with OSA are at greater risk of complications after bariatric surgery (RR = 1.23 [CI: 1.01, 1.5], P = 0.04), driven mostly by an increased risk of cardiac complications (RR = 2.44 [CI: 1.26, 4.76], P = 0.009). There were no significant differences between the OSA and non-OSA cohorts in the other outcome variables (respiratory complications, length of stay, 30-day readmission and need for ICU admission).

CONCLUSION

Following bariatric surgery, patients with OSA must be managed carefully due to the increased risk of cardiac complications. However, patients with OSA are not more likely to require a longer length of stay or readmission.

The association between obstructive sleep apnoea and wound healing: a systematic review

Purpose

Obstructive sleep apnoea (OSA) is a common, significantly underdiagnosed sleep-related breathing disorder, characterised by upper airway collapse and resultant intermittent hypoxia. Oxygen plays an important role in collagen synthesis and as a result in wound healing. An association between OSA and wound healing has not been clearly delineated. A systematic review was performed to understand this association.

Methods

Randomised controlled trials, cohort, cross-sectional and case–control studies evaluating the relationship between OSA or OSA-related symptoms and wound healing in adult populations were searched in the systematic review using electronic databases PubMed, EMBASE and Ovid MEDLINE.

Main results

A total of 11 cohort studies and 1 case–control study with a total of 58,198,463 subjects were included. Most studies suggest that patients diagnosed with OSA or who are at high risk of having OSA are more likely to suffer from wound complications. Patients with OSA have been found to be at higher risk for post-operative wound infection and wound dehiscence. Contradictory results were obtained on time to heal, with one study concluding that individuals with OSA were more likely to heal earlier when compared to patients without OSA. Quality of evidence, however, was deemed very low due to high risk of bias.

Conclusions

This systematic review did identify an association between OSA and wound healing. However, due to the very low-quality evidence, further research is warranted to better characterise this association and investigate whether or not treating OSA can indeed affect wound healing.

Preoperative Assessment of Obstructive Sleep Apnea in Bariatric Patients Using Polysomnography or Polygraphy

BACKGROUND

Preoperative assessment of obstructive sleep apnea (OSA) in patients scheduled for bariatric surgery can be performed by in-laboratory polysomnography (PSG) or by portable polygraphy (PP) at home. We aimed to evaluate the association between PSG/PP, OSA diagnosis, and implementation of continuous positive airway pressure (CPAP) therapy.

METHODS

All patients who underwent bariatric surgery from 2015 to 2017 were retrospectively reviewed. Patients underwent preoperative PSG or PP, based on prevailing protocols or at the physician's discretion. Logistic regression analyses were performed to determine predictors of CPAP implementation. OSA-related postoperative complications were analyzed in both groups.

RESULTS

During the study period, 1464 patients were included. OSA was diagnosed in 79% of 271 patients undergoing PSG, compared to 64% of 1193 patients undergoing PP (p < 0.001), with median apnea-hypopnea index (AHI) of 15.8 and 7.7, respectively. CPAP treatment was initiated in 52% and 27% of patients, respectively, p < 0.001. Predictors (with adjusted odds ratio) in multivariate regression analysis for CPAP implementation were as follows: male gender (5.15), BMI ≥ 50 (3.85), PSG test (2.74), hypertension (2.38), and age ≥ 50 (1.87). OSA-related complications did not differ between groups (p = 0.277).

CONCLUSION

Both PSG and PP are feasible options for preoperative OSA assessment in bariatric patients. When PP is performed, some underdiagnosis may occur as cases of mild OSA may be missed. However, clinically relevant OSA is detected by both diagnostic tools. No difference in OSA-related complications was found. PP is a safe, less invasive option and can be considered as a suitable measure for OSA assessment in this population.

Patients with sleep-disordered breathing for bariatric surgery

The prevalence of patients with obesity continues to rise worldwide and has reached epidemic proportions. There is a strong correlation between obesity and sleep-disordered breathing (SDB), and, in particular, obstructive sleep apnea (OSA). OSA is often undiagnosed in the surgical population. Bariatric surgery has been recognized as an effective treatment option for both obesity and OSA. Laparoscopic bariatric procedures, particularly laparoscopic sleeve gastrectomy (LSG), have become the most frequently performed procedures. OSA has been identified as an independent risk factor for perioperative complications and failure to recognize and prepare for patients with OSA is a major cause of postoperative adverse events, suggesting that all patients undergoing bariatric surgery should be screened preoperatively for OSA. These patients should be treated with an opioid-sparing analgesic plan and continuous positive airway pressure (CPAP) perioperatively to minimize respiratory complications. With the number of bariatric surgical patients with SDB likely to continue rising, it is critical to understand the best practices to manage this patient population.

Polysonographic changes in obese patients with indication of bariatric surgery

INTRODUCTION

obstructive Sleep Apnea Syndrome (OSAS) is a serious confition that compromises the quality of life and survival of patients. Its main risk fator in adults is obesity and the gold standard test for diagnosis is polysomnography (PSG), mainly through the apneia-hypopnea index (AHI). Objective: to analyze the sleep pattern of obese patients with indication for bariatric surgery, determining the main polisomnographic parameters compromised by obesity.

METHODS

This work is a cross-sectional study with analysis of polysomnography perfomed in patients with obesity in the peroperative period of bariatric surgery at a clinic in Vitória da Conquista/BA during 2017. The Epi Info 7 platform was used for analysis of the data.

RESULTS

58 polysomnographic reports were analyzed, with 56,9% morbdly obese and 43,1% non-morbid. The prevalence of OSAS was 70,68% and de AHI ranged from zero to 84,6 with a mean of 19,47±22,89 e/h. morbidly obese, compared to "non-morbid", had a longer saturation time below 80% and 90% (0,4±0,93 vs. 0,12±0,45 e 4,87±7,38 vs. 1,36±2,87 respectively; p-value=0,02 in both), worse index respiratory disorders ((29,24±25,36 vs. 16,88±16,21; p-value=0,02), higher AHI (24,71±25,68 vs. 12,56±16,67; p-value=0,02), higher hypopnea index values (16,41±17,10 vs. 6,99±8,52; p-value=0,006) and lower minimum saturation (78,24±9,80 vs. 85,24±6,33; p-value=0,004).

CONCLUSIONS

the high prevalence of OSAS found confirms its indication in the preoperative period of bariatric surgery. The main respiratory event involved in most individuals with OSAS was the hypopnea index.

Healthcare utilization after elective surgery in patients with obstructive sleep apnea - analysis of a nationwide data set

BACKGROUND

Obstructive sleep apnea is prevalent among those undergoing elective surgery and likely introduces a risk of adverse outcomes. To understand its impact, we aimed to compare healthcare utilization in postsurgical patients with obstructive sleep apnea compared to controls matched on the surgical care environment.

METHODS

This is a retrospective case-control cohort study using a nationwide database. Among patients undergoing elective surgical procedures during 2009-2014, we compared patients with obstructive sleep apnea with those without obstructive sleep apnea. The two cohorts were matched based on age, sex, type of surgery, performing surgeon, the hospital where the procedure was performed, and various All-Patient-Refined Diagnosis-Related-Groups severity indices. The primary effect of interest was short-term healthcare utilization. We also compared long-term hospital admissions, intensive care unit admissions, emergency room visits and outpatient visits.

RESULTS

47,719 subjects and controls were matched on a 1:1 basis. As the subjects were matched, the two groups did not differ on age, percent female, and various Diagnosis-Related-Groups severity indices. The obstructive sleep apnea group had more comorbid conditions and a higher Elixhauser index. Short-term healthcare utilization measured by the length of stay and mortality related to index procedure did not increase in the sleep apnea group. In hierarchical logistical regression analysis, the presence of sleep apnea predicted higher long-term health care utilization.

CONCLUSIONS

Our data suggests that the presence of sleep apnea was not associated with increased post elective surgical length of stay and mortality; however, the presence of obstructive sleep apnea was associated with long-term health care utilization.

Impact of obstructive sleep apnea-related symptoms on surgical wound complications in breast cancer patients: pilot study in a tertiary health center in Turkey

PURPOSE

Wound healing is an important factor influencing morbidity following surgical procedures. The association of obstructive sleep apnea (OSA) with numerous postoperative complications has been previously reported. In this study, we report the impact of OSA-related symptoms on wound complications in breast cancer patients in the postoperative period.

METHODS

Breast cancer patients were enrolled for a prospective observational study. Outcome measures included sociodemographic data, self-reported sleep-wake questionnaires (Berlin questionnaire, STOP-BANG, and Epworth sleepiness scale [ESS]) as well as type of surgery, smoking status, duration of anesthesia, the need for postoperative opioid drugs, and complications for surgical wounds. Patients' general preoperative health status was quantified by using American Society of Anesthesiologists (ASA) scores.

RESULTS

A total of 132 women were included in the study, of whom 61% (n = 81) underwent mastectomy, and 39% (n = 51) had breast conserving surgery. Mean ESS score of the study group was 7.7 ± 0.5. Multivariant analysis identified, either being at medium high risk by STOP-BANG questionnaire (OR:1.77, p: 0.04) or being at high risk by Berlin questionnaire (OR:1.96, p: 0.04) as well as high BMI (OR:2.76 95% CI:1.73-4.65, p: 0.02), smoking history (OR:3.04 95% CI: 2.25-3.86, p: 0.01) and type of surgery (OR:2.64 95% CI: 1.63-2.89, p: 0.03) were independent factors for wound healing.

CONCLUSIONS

The study results suggest that patients with high risk for OSA have a tendency to develop postoperative wound complications after breast cancer surgery. This study lays groundwork for further scrutiny using more robust methodology.

Clinical practice guidelines of the European Association for Endoscopic Surgery (EAES) on bariatric surgery: update 2020 endorsed by IFSO-EC, EASO and ESPCOP

BACKGROUND

Surgery for obesity and metabolic diseases has been evolved in the light of new scientific evidence, long-term outcomes and accumulated experience. EAES has sponsored an update of previous guidelines on bariatric surgery.

METHODS

A multidisciplinary group of bariatric surgeons, obesity physicians, nutritional experts, psychologists, anesthetists and a patient representative comprised the guideline development panel. Development and reporting conformed to GRADE guidelines and AGREE II standards.

RESULTS

Systematic review of databases, record selection, data extraction and synthesis, evidence appraisal and evidence-to-decision frameworks were developed for 42 key questions in the domains Indication; Preoperative work-up; Perioperative management; Non-bypass, bypass and one-anastomosis procedures; Revisional surgery; Postoperative care; and Investigational procedures. A total of 36 recommendations and position statements were formed through a modified Delphi procedure.

CONCLUSION

This document summarizes the latest evidence on bariatric surgery through state-of-the art guideline development, aiming to facilitate evidence-based clinical decisions.

Impact of Preoperative Anemia on Postoperative Kidney Function Following Laparoscopic Bariatric Surgery

BACKGROUND

Preoperative anemia is a risk factor for acute kidney failure after high-risk surgeries. We assessed the impact of preoperative anemia on kidney function in an obese Asian population after laparoscopic bariatric surgery.

METHODS

Patient characteristics, comorbidities, type of surgery, perioperative profiles, eGFR, and micronutrition were retrospectively reviewed in 341 patients with obesity undergoing bariatric surgery. All patients, who had a preoperative estimated glomerular filtration rates (eGFR) ≥ 90 mL/min/1.73 m², were followed for 1 year and assigned to one of two groups: anemia or non-anemia group. Preoperative anemia was determined based on hemoglobin concentration.

RESULTS

The Pearson's correlation coefficient between preoperative body mass index (BMI) and preoperative eGFR of all patients was 0.169 (p = 0.005). Preoperatively, there were no significant differences in age, BMI, and eGFR between the anemia (n = 38) and non-anemia groups (n = 303). Patients in the anemia group had lower hemoglobin concentration at baseline, 1 month, and 12 months after surgery than those in the non-anemia group. Postoperative eGFR levels at 1 month (p = 0.993) and 1 year (p = 0.118) as well as hospital stay (p = 0.941) were comparable between the two groups. However, the percentage weight loss was significantly higher in the non-anemia group than that in the anemia group 1 year after bariatric surgery (30.0 ± 7.3% vs. 27.0 ± 8.1%; p = 0.041).

CONCLUSIONS

Preoperative anemia did not negatively impact kidney function following laparoscopic bariatric surgery during the 12-month follow-up. Considering the potential adverse impact of anemia on postoperative weight loss, preoperative correction of anemia may be recommended.

Prevalence of risk for sleep apnea among hospitalized patients who survived a medical emergency team activation

STUDY OBJECTIVES

Sleep-disordered breathing (SDB) is a common disorder that causes people to stop breathing in their sleep, and obstructive sleep apnea (OSA) is the most common form of SDB in the general population. Because OSA is often undiagnosed and undermanaged, it has been associated with adverse events and morbidity in hospitalized patients. The purpose of the study was to evaluate prevalence of OSA risk in a population of patients who survived a medical emergency team (MET) activation during hospitalization.

METHODS

This prospective study was conducted at a hospital in the Midwest in 2014. Patients who survived a MET activation and consented to participate were administered the STOP-Bang questionnaire and asked other health and lifestyle questions. Review of the medical record was conducted to ascertain patient characteristics, comorbidities, and medications. Differences were assessed using Kruskal-Wallis one-way analysis of variance and the chi-square test.

RESULTS

Of 148 study patients, median age was 68 years (interquartile range: 55-78) and 15% were morbidly obese (body mass index ≥ 40 kg/m²). Fifty percent of patients (n = 74) were found to be at high risk for OSA, yet only 38% (n = 28) of those patients received a previous diagnosis of OSA. Variables available in the medical record were highly correlated with the overall STOP-Bang score (r =. 75, P < .001).

CONCLUSIONS

Half of patients who survived a MET activation during hospitalization screened at high risk for OSA. Standardized screening for risk of sleep apnea, as well as a truncated risk score generated by variables in the medical record, could guide clinical decision making in this at-risk population.

How Relevant Is Pre-operative Obstructive Sleep Apnoea in the Asymptomatic Bariatric Surgery Patient?

INTRODUCTION

The American Academy of Sleep Medicine recommends patients attending for bariatric surgery (BS) to be evaluated for obstructive sleep apnoea (OSA) as untreated OSA is associated with a greater risk of post-operative complications. Not all bariatric patients have symptoms of OSA and their phenotype may be at less risk than the typical sleep clinic phenotype. Therefore, all patients may not require pre-operative sleep studies. This study aimed to establish whether screened and unscreened BS patients are at increased risk of post-operative complications.

METHODS

A retrospective review of BS patients at a single centre, June 2008-May 2017. Demographic data, sleep study outcomes, post-operative complications, length of stay (LOS), intensive care unit (ICU) admission, and readmission rates were reviewed.

RESULTS

A total of 510 patients underwent gastric bypass, sleeve gastrectomy, or gastric banding. 385/510 (75.5%) were female. Mean age was 46 ± 11.27 years, mean BMI was 49 kg/m² ± 7.42. OSA was diagnosed in 300/510 (58.8%) and normal sleep in 57/510 (11.2%). OSA was not associated with increased post-operative complications. No significant difference between screened and unscreened patients for the development of post-operative pulmonary or cardiac complications, (p = 0.607, p = 0.827, respectively). Increasing age was a predictor for pulmonary (p = 0.011) and cardiac (p = 0.018) complications.

CONCLUSION

OSA is very prevalent in morbidly obese patients. The lack of association between patients diagnosed with OSA and unscreened patients, and post-operative complications suggests that not all patients require pre-operative sleep studies. Further studies may help identify which patients can safely avoid OSA screening.

Safety in Acute Pain Medicine-Pharmacologic Considerations and the Impact of Systems-Based Gaps

Objective

In the setting of an expanding prevalence of acute pain medicine services and the aggressive use of multimodal analgesia, an overview of systems-based safety gaps and safety concerns in the setting of aggressive multimodal analgesia is provided below.

Setting

Expert commentary.

Methods

Recent evidence focused on systems-based gaps in acute pain medicine is discussed. A focused literature review was conducted to assess safety concerns related to commonly used multimodal pharmacologic agents (opioids, nonsteroidal anti-inflammatory drugs, gabapentanoids, ketamine, acetaminophen) in the setting of inpatient acute pain management.

Conclusions

Optimization of systems-based gaps will increase the probability of accurate pain assessment, improve the application of uniform evidence-based multimodal analgesia, and ensure a continuum of pain care. While acute pain medicine strategies should be aggressively applied, multimodal regimens must be strategically utilized to minimize risk to patients and in a comorbidity-specific fashion.

Respiratory complications of anaesthesia

Postoperative pulmonary complications are a major determinant of outcome for patients and consume huge resources within hospital, particularly in critical care. Prediction and anticipation of postoperative pulmonary complications are vital for patient selection and, in some cases, for informed patient consent. Being able to assess the likelihood of postoperative pulmonary complications also allows research into methods to reduce them by allowing allocation of patients to the appropriate arms of research trials. Some patients have pre-operative characteristics or belong to patient groups such as those with chronic obstructive pulmonary disease or obstructive sleep apnoea, where techniques and evidence-based guidance to avoid or reduce complications are becoming established. Intra-operative ventilation and the use of lung-protective ventilation may be helpful during major surgery, but studies looking at reduced tidal volumes, recruitment and levels of positive end-expiratory pressure, have this far only led to a degree of consensus in terms of tidal volume, although parameters that predispose to postoperative pulmonary complications are becoming clearer. Optimal postoperative care in terms of analgesia, positioning, physiotherapy and mobilisation is another developing area. Techniques such as continuous positive airways pressure, non-invasive ventilation and high-flow nasal humidified oxygen appear to show some benefit, but the exact roles, pressures and timings of each are currently being explored. Much remains to be researched and developed into evidence-based practice.

Pre-operative respiratory optimisation: an expert review

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

Sleep Study and Oximetry Parameters for Predicting Postoperative Complications in Patients With OSA

In the surgical setting, OSA is associated with an increased risk of postoperative complications. At present, risk stratification using OSA-associated parameters derived from polysomnography (PSG) or overnight oximetry to predict postoperative complications has not been established. The objective of this narrative review is to evaluate the literature to determine the association between parameters extracted from in-laboratory PSG, portable PSG, or overnight oximetry and postoperative adverse events. We obtained pertinent articles from Ovid MEDLINE, Ovid MEDLINE In-Process & Other Non-Indexed Citations, and Embase (2008 to December 2017). The search included studies with adult patients undergoing surgery who had OSA diagnosed with portable PSG, in-laboratory PSG, or overnight oximetry that reported on specific sleep parameters and at least one adverse outcome. The search was restricted to English-language articles. The search yielded 1,810 articles, of which 21 were included in the review. Preoperative apnea-hypopnea index (AHI) and measurements of nocturnal hypoxemia such as oxygen desaturation index (ODI), cumulative sleep time percentage with oxyhemoglobin saturation (Spo₂) < 90% (CT90), minimum Spo₂, mean Spo₂, and longest apnea duration were associated with postoperative complications. OSA is associated with postoperative complications in the population undergoing surgery. Clinically and statistically significant associations between AHI and postoperative adverse events exists. Complications may be more likely to occur in the category of moderate to severe OSA (AHI ≥ 15). Other parameters from PSG or overnight oximetry such as ODI, CT90, mean and minimal Spo₂, and longest apnea duration can be associated with postoperative complications and may provide additional value in risk stratification and minimization.

Prevalence of Obstructive Sleep Apnoea Among Patients Admitted for Bariatric Surgery. A Prospective Multicentre Trial

BACKGROUND

Obesity has become one of the greatest public health concerns worldwide and is known to be the most important risk factor for obstructive sleep apnoea (OSA). Prevalence of OSA has increased over the last two decades, but it is estimated that the majority of cases still remain undiagnosed. The aim of this study was to investigate the prevalence of OSA in Finnish bariatric surgery candidates.

METHODS

In this prospective multicentre study, standard overnight cardiorespiratory recording was conducted in 197 consecutive patients from three different hospitals. A sleep questionnaire was also administered. Anthropometric and demographic measurements included age, weight, body mass index (BMI) and waist and neck circumference.

RESULTS

Altogether, 71 % of the patients were diagnosed with OSA. The prevalence was higher in males (90 %) than in females (60 %) (p < 0.001). In OSA patients' group, the mean neck and waist circumference was larger (p < 0.001) and the body weight higher (p < 0.01) than in non-OSA group. When separating patients by gender, a significant difference remained only concerning neck circumference in female patients.

CONCLUSIONS

OSA is very common among bariatric surgery patients, especially in men. Considering this and the increased long-term morbidity and mortality generally related to OSA, a routine screening for OSA seems indicated in bariatric patients, particularly men.

Predictors of Perioperative Acute Kidney Injury in Obese Patients Undergoing Laparoscopic Bariatric Surgery: a Single-Centre Retrospective Cohort Study

BACKGROUND

Obesity has been associated with increased risk of perioperative acute kidney injury (AKI). We aim to establish the incidence of AKI among patients undergoing laparoscopic bariatric surgery and identify potential risk factors.

METHODS

Records of 1230 patients who underwent laparoscopic bariatric surgery in a tertiary centre from 1 December 2009 to 31 January 2014 were retrospectively studied. AKI diagnosis was made by comparing the baseline and post-operative serum creatinine to determine the presence of predefined significant change based on the Kidney Disease: Improving Global Outcomes (KDIGO) definition. Univariate analyses were performed to determine significant clinical factors, and multiple logistic regression analysis was subsequently done to determine independent predictors of AKI.

RESULTS

Thirty-five (2.9 %) patients developed AKI during the first 72 h post-surgery. Multivariate logistic regression analysis revealed impaired renal function (OR 10.429, 95 % CI 3.560 to 30.552), use of angiotensin-converting enzyme inhibitors and angiotensin II receptor blockers (OR 3.038, 95 % CI 1.352 to 6.824), and body mass index (OR 1.048, 95 % CI 1.005 to 1.093) as independent predictors of perioperative acute kidney injury in the obese patients who underwent laparoscopic bariatric surgery.

CONCLUSIONS

We found that the incidence of perioperative AKI among patients who underwent laparoscopic bariatric surgery is at 2.9 %. Impaired renal function, use of angiotensin-converting enzyme inhibitors and angiotensin II receptor blockers and raised body mass index were found to be independent predictors of AKI. Patients with these risk factors could be considered at risk for developing perioperative AKI, and extra perioperative vigilance should be undertaken.

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

Supplemental Digital Content is available in the text.

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.

Continuous Positive Airway Pressure Mitigates Opioid-induced Worsening of Sleep-disordered Breathing Early after Bariatric Surgery

BACKGROUND

Bariatric surgery patients are vulnerable to sleep-disordered breathing (SDB) early after recovery from surgery and anesthesia. The authors hypothesized that continuous positive airway pressure (CPAP) improves postoperative oxygenation and SDB and mitigates opioid-induced respiratory depression.

METHODS

In a randomized crossover trial, patients after bariatric surgery received 30% oxygen in the postanesthesia care unit (PACU) under two conditions: atmospheric pressure and CPAP (8 to 10 cm H2O). During 1 h of each treatment, breathing across cortical arousal states was analyzed using polysomnography and spirometry. Arousal state and respiratory events were scored in accordance with American Academy of Sleep Medicine guidelines. Data on opioid boluses in the PACU were collected. The primary and secondary outcomes were the apnea hypopnea index (AHI) and apnea after self-administration of opioids in the PACU. Linear mixed model analysis was used to compare physiologic measures of breathing.

RESULTS

Sixty-four percent of the 33 patients with complete postoperative polysomnography data demonstrated SDB (AHI greater than 5/h) early after recovery from anesthesia. CPAP treatment decreased AHI (8 ± 2/h vs. 25 ± 5/h, P < 0.001), decreased oxygen desaturations (5 ± 10/h vs. 16 ± 20/h, P < 0.001), and increased the mean oxygen saturation by 3% (P = 0.003). CPAP significantly decreased the respiratory-depressant effects observed during wakefulness-sleep transitions without affecting hemodynamics. The interaction effects between CPAP treatment and opioid dose for the dependent variables AHI (P < 0.001), inspiratory flow (P = 0.002), and minute ventilation (P = 0.015) were significant.

CONCLUSIONS

This pharmacophysiologic interaction trial shows that supervised CPAP treatment early after surgery improves SDB and ameliorates the respiratory-depressant effects of opioids without undue hemodynamic effects.

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.

Perioperative sleep apnea: a real problem or did we invent a new disease?

Depending on the subpopulation, obstructive sleep apnea (OSA) can affect more than 75% of surgical patients. An increasing body of evidence supports the association between OSA  and perioperative complications, but some data indicate important perioperative outcomes do not differ between patients with and without OSA. In this review we will provide an overview of the pathophysiology of sleep apnea and the risk factors for perioperative complications related to sleep apnea. We also discuss a clinical algorithm for the identification and management of OSA patients facing surgery.

Factors associated with prolonged anesthesia recovery following laparoscopic bariatric surgery: a retrospective analysis

BACKGROUND

Phase I postanesthesia recovery is often prolonged after laparoscopic bariatric surgery. We hypothesized that postoperative respiratory depression is a major contributor to this delayed recovery.

METHODS

Medical records of all patients who had a laparoscopic bariatric surgical operation from January 1, 2009, to December 31, 2012, were reviewed for clinical, anesthetic, and postanesthesia variables. Recoveries were defined as discharge from the recovery room in ≤90 min and in >90 min (prolonged postanesthesia recovery). We compared characteristics of patients without prolonged recovery to those with prolonged recovery.

RESULTS

Of 781 bariatric patients, 304 (38.9 %) had prolonged recovery. These patients had more respiratory depression (29 vs 6 patients), more postoperative nausea and vomiting (106 vs 92 patients), more treatments of hypertension in the recovery room (49 vs 33 patients), and more opioid treatment (median intravenous morphine equivalents [interquartile range], 10.0 [3.0-15.0] vs 5.0 [0.0-10.5]) (P < 0.001 for all). On multivariable analysis, preoperative history of hypertension (P = 0.03), fewer prophylactic antiemetics received (P = 0.02), and longer surgical duration (P = 0.03) were associated with prolonged postanesthesia recovery.

CONCLUSIONS

Inadequate antiemetic prophylaxis and the treatment of postoperative hypertension were associated with prolonged postanesthesia recovery. Surprisingly, diagnosis of obstructive sleep apnea was not associated with prolonged recovery, which may be attributable to use of continuous positive airway pressure devices following emergence from anesthesia. Prolonged recovery in patients treated for hypertension may be related to institutional guidelines that require additional monitoring time after these medications are administered.