Sleep apnoea syndrome and surgery

Abstract

Obstructive sleep apnoea syndrome is essentially a functional disorder with underlying anatomical predisposing risk factors. Abnormal control of breathing and, in particular, the control of upper airway muscle tone, is the crux of obstructive sleep apnoea syndrome. It is manifested as increased tendency to the collapse of the upper airway. Special considerations should therefore be taken when a sleep apnoeic patient is to be anaesthetized. Unfortunately, the vast majority of patients with obstructive sleep apnoea syndrome submitted to any surgical procedure probably have not had their obstructive sleep apnoea syndrome diagnosed. Patients' evaluation for surgery, especially in middle-aged, overweight men, should include questions about snoring and daytime somnolence and possibly polysomnography if obstructive sleep apnoea syndrome is suspected. Various anaesthetic agents have been shown selectively to decrease the activity of the upper airway muscle. The muscle most susceptible to this effect is the genioglossus, which makes the tongue liable to prolapse into the throat, resulting in obstruction to air flow. Thus, patients with obstructive sleep apnoea syndrome are at high risk of upper airway obstruction after administration of anaesthetics, particularly when they are given as premedication or after extubation, until the anaesthetic is metabolized and eliminated. Several surgical procedures have been specifically developed for the treatment of obstructive sleep apnoea syndrome including nasal, uvulopalatopharyngeal and head and neck surgery, weight reduction surgery and tracheostomy. There remains a lack of consensus regarding the indications, success rate, complications and long-term prognosis associated with these procedures. The current status of these surgical procedures, as well as special anaesthetic considerations in obstructive sleep apnoea syndrome, are reviewed.