We analyzed the role of sleep position in obstructive sleep apnea syndrome (OSAS). The polysomnograms of 120 patients with sleep apnea syndrome were analyzed. We associated the apnea hypopnea index (AHI) of the supine position with the AHI of the other positions. Patients were stratified in a group of positional patients (PP) (AHI supine >or= 2 x AHI other positions) and a group of non-positional patients (NPP). In 55.8% of our patients, OSAS was position dependent. PP patients were significantly (6.7 years) younger. BMI and AHI were higher in the NPP group, but the difference was not significant. Level of obstruction in the upper airway (retropalatinal vs retrolingual vs both levels) as assessed by sleep endoscopy was not significantly different between the two groups. Total sleep time (TST) was equal in both groups, but the average time in supine position was 37 min longer in the PP group. This study confirms the finding that in more than 50% of patients, OSAS is position dependent. Apart from age, no patient characteristics were found indicating the position dependency. Overall AHI does not identify positional OSAS.

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This study demonstrates that HTP, in particular as primary treatment in cases of obstruction at tongue base level, is a valuable addition to the therapeutic armamentarium of moderate to severe OSAS. Selection criteria are moderate to severe OSAS with preferably a body mass index less than 27, multilevel obstruction with emphasis on the base of tongue, small tonsils, and normal uvula, without a floppy epiglottis or a palatal stenosis after UPPP.

No positive correlation exists between a large tongue and obstruction at tongue base level. In both groups, retropalatal obstruction occurred more often than retrolingual obstruction. Sleep endoscopy provides qualitative insight into important changes during sleep in patients with SUS and OSAS. In addition, anatomic aberrations are clearly visualized in a dynamic setting. Classification of the size of the tongue, as assessed by the MMS, may be of great importance as well.

Sleep is an integral part of human existence and is now, more than ever, the subject of clinical and research interest. Why do we spend approximately one third of our lives asleep? Sleep probably has a recovery function, especially for the brain. Throughout rapid eye movement sleep, neuronal connections in the catecholamine system are created, and this activity is essential to maintain cognitive function.w1 During rapid eye movement sleep in particular, the body is at its most relaxed state, and a three dimensional collapse of muscle (musculus genioglossus and musculus geniohyoideus) and fatty tissue around the upper airway may cause obstruction.1 When a pre-existent narrowing and slackening of the upper airway is also present, 2 apnoeas (complete cessation of breathing for 10 seconds or more) or hypopnoeas ( > 50% diminishing of airflow or oxygen desaturations > 3% for 10 seconds or more) may result. The prevalence of obstructive sleep apnoea in middle age is 2% for women and 4% for men.3 In practice, obstructive sleep apnoea seems to be under-reported; obstructive sleep apnoea is undiagnosed in an estimated 80% of patients. 4 Patients with obstructive sleep apnoea are particularly vulnerable during anaesthesia and sedation. w2This is not only the case for operations or other invasive interventions aiming at alleviation of obstructive sleep apnoea through reduction of the obstructive upper airway; even after surgery not related to obstructive sleep apnoea, such as hip and knee operations, patients with obstructive sleep apnoea are at risk of developing respiratory and cardiopulmonary complications postoperatively. Serious complications include reintubations and cardiac events.6 Anaesthetic management must focus on and deal with the increased likelihood of morphological alterations of the upper airway leading to an increased rate of difficulties in securing and maintaining a patent airway. 7In this review we discuss the various anaesthetic aspects of obstructive sleep apnoea, including preoperative, perioperative, and postoperative points of special interest. We also cover the various management options.