Respiratory effects of extradural nerve block in the postoperative period.

The effects of continuous extradural block in the postoperative period on arterial hypoxaemia are discussed. Comparing two matched groups of patients following upper abdominal surgery, one receiving continuous extradural analgesia and one narcotic analgesia, there were small but statistically insignificant improvements in PaO2 in the former group. It was concluded that abdominal muscle spasm is not an important cause of postoperative arterial hypoxaemia.