[Late episodic hypoxemia and variation in heart rate following major abdominal surgery]

In thirteen patients who were submitted to elective major abdominal surgery, the heart rate and arterial oxygen saturation were monitored continuously on the preoperative night-to-day prior to operation and the first and second postoperative nights (from 11 pm till 7.30 am). The heart rate increased by an average of approximately 22 beats/minute (p less than 0.005) and the oxygen saturation decreased approximately 4.5% (median) (p less than 0.003) after the operation. During the second postoperative night, two patients had 120 and 372 episodes respectively of sudden decrease in saturation to less than 80%. On the morning of the third day, the second of these patients developed cardiac arrhythmia requiring treatment. In one of these patients, the episodes were closely correlated with increase in the heart rate. No connection was observed between administration of opiates and disturbances in oxygen saturation or heart rate. The clinical relevance of episodic decrease in saturation in the late postoperative phase is still unknown but may be of significance for the development of cardiac and cerebral dysfunctions.