Featured Articles from March 2013

Society for Ambulatory Anesthesia Consensus Statement on Preoperative Selection of Adult Patients With Obstructive Sleep Apnea Scheduled for Ambulatory Surgery

The Society for Ambulatory Anesthesia task force on practice guidelines developed a consensus statement for the selection of patients with OSA scheduled for ambulatory surgery. A systematic review of the literature was conducted according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. Although the studies evaluating perioperative outcome in OSA patients undergoing ambulatory surgery are sparse and of limited quality, they do provide useful information that can guide clinical practice. Patients with a known diagnosis of OSA and optimized comorbid medical conditions can be considered for ambulatory surgery, if they are able to use a continuous positive airway pressure device in the postoperative period. Patients with a presumed diagnosis of OSA, based on screening tools such as the STOP-Bang questionnaire, and with optimized comorbid conditions, can be considered for ambulatory surgery, if postoperative pain can be managed predominantly with nonopioid analgesic techniques. On the other hand, OSA patients with nonoptimized comorbid medical conditions may not be good candidates for ambulatory surgery


Sleep and Antibody Response to the Hepatitis B Vaccination

Experimental evidence links poor sleep and susceptibility to infectious illness; however, it remains to be determined if naturally occurring sleep is associated with immune responses critical to protection against infection. This observational study investigated whether sleep, assessed in the natural environment via actigraphy and sleep diary, predicted the magnitude of antibody responses to a novel antigen (i.e., hepatitis B) in a sample of 125 healthy, community volunteers in midlife. Analyses revealed that shorter actigraphy-derived sleep duration was associated with lower secondary antibody responses to vaccination, independent of study covariates. Further shorter sleep duration, assessed by both diary and actigraphy, predicted decreased likelihood of being clinically protected (anti-hepatitis B surface antigen immunoglobin G ³ 10 mIU/ml) 6-months after the conclusion of the vaccination series. Measures of sleep efficiency and subjective quality were unrelated to vaccination response. This study provides intriguing preliminary evidence that short sleep duration in the natural environment negatively affects in vivo antibody responses to novel antigens, which may have important implications for immunologically vulnerable populations experiencing short sleep.


Experimental Pain and Opioid Analgesia in Volunteers at High Risk for Obstructive Sleep Apnea

Obstructive sleep apnea (OSA) is characterized by recurrent nocturnal hypoxia and sleep disruption, both of which have been shown to impact pain and /or analgesia behavior. Thresholds and tolerances for experimentally induced heat– and cold– related pain, were assessed in volunteers at risk for OSA, at baseline and during an opioid (remifentanil) infusion. Volunteers were also underwent over-night polysomnography and blood draw for determination of inflammatory and hypoxia markers. Mixed linear regression analysis showed that increased serum levels of inflammatory (tumor necrosis factor-a, interleukin-1b) and hypoxia (insulin growth factor binding protein-1) markers were associated with an enhanced sensitivity to the analgesic effect of remifentanil. Statistical model adjustment for the presence of inadequate /fragmented sleep in these subjects, support an independent association of hypoxia and inflammation with opioid analgesic pharmacology. Further studies in larger populations and different settings are required to establish the potential clinical significance of these findings.