Postoperative hypoxaemia and oxygen therapy.

To observe the duration of hypoxaemia 8 patients were monitored every day for the first 7 days following upper abdominal surgery. Three of these patients who had failed to regain their preoperative PO2 value by the seventh postoperative day were further monitored on alternate days until the fourteenth postoperative day. A further 3 patients were similarly monitored on alternate days for 14 days. In another group of 10 patients blood gases were monitored every 4 h for the first 48 h following major abdominal surgery, during which time the patients were given 35 per cent oxygen for the first 24 h after operation. (All patients in this group had a diminished respiratory reserve preoperatively to a sufficient degree to warrant admission to the intensive therapy unit postoperatively, and these patients were treated with oxygen for 24 h, as is the practice in our unit and in other surgical units.) Oxygen was administered using a Ventimask at 8 l/min (British Medical Journal, 1972). Nine of the 10 patients did not show postoperative hypoxaemia while being treated with 35 per cent oxygen, although the PO2 value attained were lower than expected. On withdrawal of oxygen after 24 h, the PO2 decreased below preoperative levels in all patients. The PO2 of 7 patients in this group decreased below 8 kPa during the second 24 postoperative hours, in 4 of whom the level fell below 6-7 kPa. Some recommendations to improve the respiratory care of the surgical patient are presented.