Clinical Adult Literature Updates from September 2018

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

The Society of Anesthesia and Sleep Medicine Guideline on Intraoperative Management of Adult Patients With Obstructive Sleep Apnea (OSA) presents recommendations based on current scientific evidence. This guideline addresses questions regarding the intraoperative care of patients with OSA, including airway management, anesthetic drug and agent effects, and choice of anesthesia type. A systematic literature search was performed to capture the current body of evidence as it relates to the intraoperative anesthetic care of patients with OSA. Based on the groundwork of this comprehensive literature review and a consensus process among the guideline member, recommendations reflect the current state of knowledge, the quality of the body of evidence and its interpretation by subject-matter experts. Deviations in practice from the guideline may be justifiable and should not be interpreted as a basis for claims of negligence.

Postoperative complications with neuromuscular blocking drugs and/or reversal agents in obstructive sleep apnea patients: a systematic review.

Neuromuscular blocking drugs (NMBD) achieve intraoperative muscle relaxation to facilitate intubation and surgical procedures. Incomplete reversal of NMBD can lead to adverse postoperative events which is of particular concern in patients with obstructive sleep apnea (OSA). This systematic review aimed to determine whether: 1) OSA patients are at higher risk of postoperative complications from the use of NMBD compared to patients without OSA, and 2) whether the choice of NMBD reversal agent would affect the risk of postoperative complications in patients with OSA. The systematic literature search revealed five eligible studies out of 4123 (2 RCTs and 3 observational studies), while the level of evidence was deemed as low to moderate. Overall, OSA patients with intraoperative NMBD use may be at higher risk for postoperative hypoxemia, respiratory failure and residual neuromuscular blockade when compared to non-OSA patients. There is some, albeit very limited evidence suggesting that NMBD reversal with sugammadex may be associated with less PPCs than neostigmine in OSA. More high-quality studies are needed.

Opioids for Acute Pain Management in Patients With Obstructive Sleep Apnea: A Systematic Review.

The intrinsic nature of opioids to suppress respiratory function is of particular concern among patients with obstructive sleep apnea (OSA). The establishment of OSA as a perioperative risk factor has raised the question of whether affected patients are at higher risk for opioid-induced respiratory depression (OIRD). This systematic review aimed to summarize current evidence with respect to perioperative OIRD, changes in sleep-disordered breathing, and alterations in pain and opioid sensitivity in patients with OSA. Overall, high-quality evidence on the comparative impact of acute opioid analgesia in OSA versus non-OSA patients is lacking. The current body of evidence is burdened by significant limitations including risk of bias and large heterogeneity among studies with regard to OSA severity, perioperative settings, outcome definitions, and the presence or absence of various perioperative drivers. Nevertheless, there is some consistency among studies with regard to a detrimental effect of opioids in the presence of OSA. With regard to OIRD, the initial 24 hours after opioid administration appear to be most critical. OSA-related changes in pain perception and opioid sensitivity may also predispose patients to higher risk for OIRD without overdosing. While high-quality evidence is needed, retrospective analyses indicate that critical, life-threatening OIRD may be preventable with a more cautious approach to opioid use and adequate monitoring.

A retrospective study of opioid prescribing patterns at hospital discharge in surgical patients with obstructive sleep apnea.

Given the implications of obstructive sleep apnea (OSA), the minimization of opioids in the perioperative setting is recommended in patients with known or suspected OSA. This retrospective analysis investigated opioid prescribing patterns among patients undergoing surgery from 1 November 2016 to 30 April 2017 at a single academic institution. Patients with known or suspected OSA by STOP-Bang were compared to those without OSA for the amount of postoperative discharge opioid medication using multivariable linear regression. Adjusted analysis showed no significant difference in the amount and rates of opioids prescribed upon discharge between OSA and non-OSA surgical patients, despite guidelines recommending opioid sparing. These findings indicate a need to implement different strategies to reduce opioids to patients with OSA.

Pattern of perioperative gabapentinoid use and risk for postoperative naloxone administration.

Preoperative gabapentinoid (gabapentin and pregabalin) administration has been associated with respiratory depression during anaesthesia recovery. This study assessed associations between chronic (home) use and perioperative (preoperative and postoperative) use of gabapentinoids, and risk for severe over-sedation or respiratory depression as inferred from the use of naloxone. Single center retrospective analysis of 128 patients who received general anaesthesia  and required naloxone administration within 48 h postoperatively. Patients were 2:1 matched on age, sex, and type of procedure. Multivariable analysis detected significant interactions between chronic and postoperative use of gabapentinoids, where continuation of chronic gabapentinoid medications into the postoperative period was associated with an increased rate of naloxone administration. Obstructive sleep apnoea and preoperative disability were also associated with an increased risk for postoperative naloxone administration. Continuation of chronic gabapentinoid medications into the postoperative period as well as OSA are associated with the increased use of naloxone to reverse over-sedation or respiratory depression.

Can STOP-Bang and Pulse Oximetry Detect and Exclude Obstructive Sleep Apnea?

Obstructive sleep apnea (OSA) is well established as a driver of postoperative complications. However, despite the high prevalence of OSA, most patients remain undetected in the perioperative setting, which highlights the need for simple screening tools. This prospective observational multicenter study aimed to investigate whether STOP-Bang and oxygen desaturation index can identify subjects with OSA. Analysis included 449 adult patients referred to a sleep clinic for OSA evaluation with ambulatory polysomnography, including pulse oximetry and the STOP-Bang questionnaire in 4 Swedish centers. The STOP-Bang score is the sum of 8 positive answers to Snoring, Tiredness, Observed apnea, high blood Pressure, Body mass index >35 kg/m, Age >50 years, Neck circumference >40 cm, and male Gender.

Overall, data showed that the STOP-Bang tool and pulse oximetry can be used to screen for OSA. A STOP-Bang score of <2 almost excludes moderate and severe OSA, whereas nearly all the patients with a STOP-Bang score ≥6 have OSA. The authors suggested the addition of nightly pulse oximetry in patients with a STOP-Bang score of 2-5 to enable OSA screening.

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

Studies have shown that Epworth sleepiness scale (ESS) is not an optimal predictor of obstructive sleep apnea (OSA). Singla et al. however, investigated the accuracy of ESS with regard to the identification of OSA patients would be improved when utilized among morbidly obese patients. This retrospective review of 232 bariatric surgery patients who underwent polysomnography and ESS assessment confirmed the ESS as a poor predictor of OSA. Nevertheless, the utility of ESS may be improved by a new formula, incorporating age and BMI.

Comparison of clinical scores in their ability to detect hypoxemic severe OSA patients.

Severe obstructive sleep apnea (sOSA) and preoperative hypoxemia are risk factors of postoperative complications. Patients exhibiting the combination of both factors are probably at higher perioperative risk. Four scores (STOP-Bang, P-SAP, OSA50, and DES-OSA) are currently used to detect OSA patients preoperatively. In the studied population, DES-OSA appears to be more effective than the three other scores to specifically detect hypoxemic sOSA patients.

Prevalence and Prediction of Obstructive Sleep Apnea Prior to Bariatric Surgery-Gender-Specific Performance of Four Sleep Questionnaires.

Bariatric surgery is a treatment option for morbid obesity leading to substantial and sustained weight loss in adults. The authors sought to assess the gender-specific performance of four sleep questionnaires (Epworth Sleepiness Scale (ESS), Fatigue Severity Scale (FSS), STOPBang, and NoSAS) to predict moderate to severe OSA in the morbidly obese population. They conclude that patients scheduled for bariatric surgery, a gender-specific difference was observed in the performance of the evaluated OSA screening questionnaires. This needs to be considered when these questionnaires are used. They suggest that there is a need for better gender-specific OSA screening algorithms in morbidly obese patients.

Brain bioenergetics during resting wakefulness are related to neurobehavioral deficits in severe obstructive sleep apnea: a 31P magnetic resonance spectroscopy study

Lower phosphorylation potential was associated with worse performance. Compromised brain bioenergetics may in part underlie the neurobehavioral deficits in untreated OSA. We speculate that better brain bioenergetics may explain why some OSA patients are relatively asymptomatic compared with others.