Postoperative obstructive sleep apnoea. Haemodynamic effects of treatment with nasal CPAP

A 74-year-old man presenting for aortic reconstructive surgery showed severe, previously undiagnosed obstructive sleep apnoea during overnight oximetry monitoring before operation. Postoperatively, in the first 4 hours following extubation, he suffered 238 episodes of respiratory obstruction. These events were associated with frequent arousals, large fluctuations in systolic and diastolic blood pressure. Administration of nasal continuous positive airways pressure abolished the obstructions and allowed an uninterrupted night's sleep, with a significantly reduced blood pressure. Subsequent dips in oxygen saturation as a result of respiratory obstruction recurred on the fifth postoperative night. We conclude that pre-operative overnight oximetry may be useful in identifying those patients at risk of postoperative upper airway obstruction. Use of nasal continuous positive airway pressure may prevent the occurrence of early postoperative obstruction and the associated haemodynamic changes.