Abstract
The mechanisms and effects of severe hypoxemia in the early postoperative period have been well documented and intensive care is routinely extended to the first to second postoperative days with adequate monitoring. Less well recognized and consequently less appreciated, however, are the effects of severe oxygen desaturation in the late postoperative period which is called episodic hypoxemia because of its on and off nature. Episodic hypoxemia occurs in association with an abnormal sleep pattern in which intense REM sleep or"REM rebound", reappears and is often accompanied with apnea in the second to fourth postoperative nights following the disappearance in the first night. Although the desatura-tion usually lasts less than two minutes, it frequently repeats and the total time of oxygen desaturation may occupy 80% of night sleep. This new type of hypoxemia has been implicated in severe postoperative complications such as myocardial infarction and delir-ium. All clinicians involved in postoperative care need to recognize the problem and should try to identify the patients at risk for whom appropriate monitoring and oxygen therapy may well be provided.
