Clinical Adult Literature Updates from June 2018

Prevalence of primary open-angle glaucoma among patients with obstructive sleep apnea

A “convenience sample” referred by Sleep Medicine for oral appliances because of continuous positive airway pressure intolerance was analyzed. The investigators determined the aggregate prevalence of the 3 POAG subtypes-“classic” open-angle glaucoma (COAG), normal-tension glaucoma (NTG), and open-angle glaucoma suspect (OAGS)-among the index population and compared it with that of same hospital’s general population. Furthermore, associations between OSA severity levels (apnea-hypopnea index [AHI]) and POAG subtypes were investigated. Results showed that among the study sample of 225 patients with OSA, 20.9% had POAG, which was significantly higher than the POAG prevalence rate among the medical center’s general population at 2.5%, (P < .00001). Severity of the breathing disorder measured by AHI, however failed to identify a significant correlation to any POAG subtype (P > .05).

The significantly increased prevalence of POAG among OSA patients suggests the need for preoperative consultations from an ophthalmologist to determine eye health and possibly an anesthesiologist to avoid potential vision loss.

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

Given the importance of preoperative screening for OSA in bariatric surgery and the predominance of female gender in this intervention, the aim of the study was to assess gender-specific performance of four sleep questionnaires. These included the Epworth Sleepiness Scale (ESS), Fatigue Severity Scale (FSS), STOP Bang, and NoSAS to predict moderate to severe OSA in this morbidly obese population. Results demonstrated a gender-specific difference in the performance of the evaluated screening questionnaires. These findings suggest the need for gender-specific OSA screening algorithms in morbidly obese patients.

Ambulatory Surgery Has Minimal Impact on Sleep Parameters: A Prospective Observational Trial

OSA is a significant postoperative concern in ambulatory surgery, while few data exist to guide clinical management. This prospective observational study aimed to measure changes in perioperative sleep parameters in orthopedic ambulatory surgery patients. Study subjects completed three unattended home sleep apnea tests: baseline before surgery, the first night after surgery (N1), and third night after surgery (N3), while anesthesia providers and surgeons were blinded and provided routine perioperative care. Results showed that ambulatory surgery had minimal effect on sleep parameters and there was no increase in adverse events among patients with either treated or untreated OSA.

Obstructive Sleep Apnea Screening Among Surgical Patients: A Quality Improvement Project

This quality improvement project prospectively screened neurosurgical patients for OSA using the STOP-Bang questionnaire and explored its relationship with respiratory complications. Scores of 5 or greater were considered as high risk and less than 5 as low risk for moderate-to-severe OSA. Postoperative respiratory complications were compared between both OSA groups. Perioperative staff and patient education included an OSA care protocol using STOP-Bang screening. Results showed that the OSA care protocol decreased the risk for postoperative respiratory complications, demonstrating that education is essential to confer safer perioperative outcomes.

Effectiveness of Apneic Oxygenation During Intubation: A Systematic Review and Meta-Analysis

Sleep disordered breathing has a strong association with difficult airways and postoperative adverse outcomes (including desaturation and reintubation). Apneic oxygenation may have an important role to play during emergency intubation. This group from Mayo Clinic conducted a systematic review and meta-analysis to evaluate the effectiveness of apneic oxygenation in airway management. Fourteen studies were included for qualitative review and 8 studies (comprising of 1,837 patients) for quantitative analysis. Apneic oxygenation decreased hypoxemia (OR 0.66; 95%CI 0.52-0.84), increased first-pass intubation success (OR 1.59; 95%CI 1.04-2.44), and increased lowest peri-intubation SpO2 (weighted mean difference 2.2%; 95%CI 0.8%-3.6%). This novel but under-utilized airway modality may have a role to play in difficult airway management in sleep-disordered breathing patients and other emergency intubations.

Obstructive sleep apnea as a risk factor associated with difficult airway management – A narrative review

It has been known that obstructive sleep apnea (OSA) is strongly associated with difficult airways, however the detailed relationship has not been clearly defined in a comprehensive review previously. The group from Toronto Western Hospital undertook a review of English-language literature up to April 2016 to determine the association between OSA and difficult airways. Ten studies were included for the qualitative analysis. The incidence of difficult tracheal intubation was found to be 2-fold higher in OSA patients versus non-OSA patients (14.5% vs. 7.7%; p=0.0002). Difficult mask ventilation occurred 3.5X more in OSA patients (2.5% vs. 0.7%; p<0.0001). This study did not find a difference in airway management difficulty with supraglottic airway devices (1.5% vs. 1.1%; p=0.38). The narrative review determined that OSA is indeed a risk factor for difficult airway.

Change in Cognition and Other Non-Motor Symptoms With Obstructive Sleep Apnea Treatment in Parkinson Disease

In this prospective observational study, 67 patients with idiopathic Parkinson’s Disease had polysomnography. Those with moderate to severe OSA were offered CPAP. Subjects were divided into those with or without CPAP and assessed at 6 and 12 months. At 6 months, patients were considered CPAP users if they had used CPAP at home for at least one month. Those who did not use CPAP or declined further treatment were considered non-users. At 12 months, those still using CPAP were considered CPAP users. At 6 months, 30 participants were using CPAP and 11 patients were not using CPAP. At 12 months 21 patients were using CPAP. The Unified Parkinson’s Disease Rating Scale part 1 and Parkinson’s Disease Sleep Scale improved from baseline in the CPAP compliant group at 6 and 12 months. The Montreal Cognitive Assessment (MoCA) and Hospital Anxiety and Depression Scale improved at 12 months. The MoCA improved in those with low baseline score and with REM sleep behavior disorder. Mean CPAP use was 3 hrs and 36 minutes at 12 months in CPAP users.

Effects of continuous positive airway pressure on cardiovascular biomarkers in patients with obstructive sleep apnea: a meta-analysis of randomized controlled trials

This meta-analysis sought to quantify the effects of CPAP on cardiovascular biomarkers (high sensitivity CRP, IL-6, TNF-alpha, augmentation index, pulse wave velocity and flow-mediated dilatiationand to establish predictors of response to CPAP. The authors included 15 RCTs with 1090 patients in the meta-analysis. They found that CPAP improves inflammatory markers hs-CRP, arterial stiffness marker Alx, and endothelial function marker FMD. The authors concluded that these biomarkers may provide information about response to treatment with CPAP.