Obstructive sleep apnoea and anaesthesia

Obstructive sleep apnoea (OSA) is a common condition affecting approximately 4% of middle-aged individuals. The condition is more common in men with a history of snoring. Patients experience fragmented sleep caused by repetitive obstruction of the upper airway during sleep. There is mounting evidence that OSA is associated with metabolic syndrome. Metabolic syndrome comprises hypertension and type 2 diabetes, with associated disturbances of lipid metabolism and central obesity that predisposes to cardiovascular disease. Sleep disruption causes excessive daytime sleepiness and patients may be a danger to themselves or others, especially when driving. Anaesthetists meet the condition frequently, and should have a high index of suspicion when assessing overweight middle-aged patients for surgery. Patients may present for ENT or maxillofacial surgery as part of the management of the condition, but the group at greatest risk comprises those who are unrecognized and therefore untreated, who present for surgery for an unrelated condition. Recent screening questionnaires have been developed to aid the anaesthetist in spotting at risk patients, and in predicting the likelihood of postoperative complications. Difficulty with intubation is common, and airway obstruction may occur under anaesthesia if opioid and sedative drugs are used without caution. Many patients also suffer from acid reflux, which may complicate induction of anaesthesia. A plan for difficult airway management is essential, and consideration should be given to carrying out an awake intubation under topical anaesthesia of the upper airway. Knowledge of treatment with nasal continuous positive airway pressure is necessary, and all staff involved should be experienced in the management of such patients during the perioperative period.