Extradural analgesia and the prevention of postoperative respiratory complications.

IN 1902 Campiche, of Lausanne, observed that chest complications are likely to occur after "operations an effect of which is to cause pain on coughing . . . and to upset expectoration and the free functioning of the abdominal pressure". Lawen, in 1912, further remarked: "if we were in a position to produce prolonged anaesthesia, lasting for several days, it is likely that the incidence of bronchitis and pneumonia following laparotomy would be decisively reduced". § Since this time it has become widely recognized that of all operations those within the abdomen, and particularly the upper abdomen, are most likely to be followed by severe pain and respiratory disturbance (King, 1933; Cutler and Hoerr, 1941; Mimpriss and Etheridge, 1944; Blodgett and Beattie, 1946; Pooler, 1949). Intra-abdominal surgery involves cutting of the skin and subcutaneous tissues, division or stretching of the muscles of the body wall, opening of the peritoneum, and interference with the viscera. Thus, with the exception of bone involvement, every possible factor in the production of postoperative pain is brought into operation. After surgery the patient must use his anterior abdominal muscles for almost every movement he wishes to make; active participation of these muscles is also required for deep breathing and even more so for coughing. It is not surprising, therefore, that the patient, when left undisturbed, lies still and breathes as quietly as possible.