The relationship between obstructive sleep apnoea and postoperative delirium and pain: an observational study of a surgical cohort.

Patients with obstructive sleep apnoea are at increased risk of adverse postoperative outcomes, such as cardiac and respiratory complications. It has been hypothesised that obstructive sleep apnoea also increases the risk for postoperative delirium and acute postoperative pain. We conducted a retrospective, observational study investigating the relationship of obstructive sleep apnoea with postoperative delirium and acute postoperative pain severity. Patients were classified as being at high risk for obstructive sleep apnoea if they had been diagnosed with this condition, or if they were positive for more than four factors using the 'STOP-BANG' screening tool. Adjusted logistic regression was used to investigate the association between obstructive sleep apnoea and postoperative delirium, and multivariable linear regression to study the relationship between obstructive sleep apnoea and postoperative pain severity. The incidence of postoperative delirium was 307 in 1441 patients (21.3%; 95%CI 19.2-23.5%). In unadjusted analysis, high risk for obstructive sleep apnoea was associated with delirium, with an odds ratio (95%CI) of 1.77 (1.22-2.57; p = 0.003). After adjustment for pre-specified variables, the association was not statistically significant with odds ratio 1.34 (0.80-2.23; p = 0.27). The mean (SD) maximum pain (resting or provoked) reported for the entire cohort was 63.8 (27.9) mm on a 0-100 mm visual analogue scale. High risk for obstructive sleep apnoea was not associated with postoperative pain severity (ß-coefficient 2.82; 95%CI, -2.34-7.97; p = 0.28). These findings suggest that obstructive sleep apnoea is unlikely to be a strong risk factor for postoperative delirium or acute postoperative pain severity.

Review of perioperative falls.

Falls are a known public health problem, and there is increasing recognition of the importance of perioperative falls for risk prediction and quality assessment. Our objective was to review existing literature regarding the occurrence, injuries, and risk factors of preoperative and postoperative falls. A systematized search of PubMed entries between 1947 and November 2015 produced 24 articles that met inclusion criteria. Most studied orthopaedic surgery patients older than 65 yr. Four were rated 'good' quality. Interrater reliability for the quality assessment was moderate (κ = 0.77). In the 3-12 months before surgery, the proportion of preoperative patients who fell ranged from 24 to 48%. Injuries were common (70%). The rate of postoperative falls ranged from 0.8 to 16.3 per 1000 person-days, with a gradual decline in the months after surgery. Injuries from postoperative falls occurred in 10-70% of fallers, and 5-20% experienced a severe injury. Risk factors were not well studied. Prospective studies reported a higher percentage of falls and fall-related injuries than retrospective studies, suggesting that there may be underdetection of falls and injuries with retrospective studies. Perioperative falls were more common than falls reported in the general community, even up to 12 months after surgery. Surgery-related falls may therefore occur beyond the hospitalization period. Future studies should use a prospective design, validated definitions, and broader populations to study perioperative falls. In particular, investigations of risk factors and follow-up after hospitalization are needed. REGISTRY NUMBER: PROSPERO registration number CRD42015029971.