Ventilatory pattern and associated episodic hypoxaemia in the late postoperative period in the general surgical ward

Episodic oxygen desaturation is frequent in the late postoperative period and seems most pronounced on the second and third postoperative nights. However, the ventilatory pattern has not been described systematically during this period. We studied the ventilatory pattern and associated arterial oxygenation using the Edentrace II equipment (impedance pneumography and pulse oximetry) on the second and third postoperative nights in 28 patients undergoing major abdominal surgery. Ventilatory disturbances were common and included periods of hypopnoea, and obstructive, central and mixed apnoeas. Overall, the median (range) respiratory disturbance index (apnoeas + hypopnoeas per h) was 12 (0-121), with the patients spending 6% (0-65%) of the night in some kind of ventilatory disturbance. It was not possible from pre-operative snoring habits to predict patients who developed postoperative ventilatory disturbances. Overall, 23% (0-100) of the hypopnoeas and 7% (0-100) of the apnoeas were associated with episodic hypoxaemia. In conclusion, ventilatory disturbances were common in the late postoperative period in the general surgical ward and often associated with episodes of oxygen desaturation.