Changes in pulmonary function during continuous epidural bupivacaine with or without morphine following upper abdominal surgery.

To assess the effect of postoperative continuous thoracic epidural infusion of bupivacaine on pulmonary function, a prospective randomized study was conducted in patients undergoing upper abdominal surgery (UAS). Sixteen patients, divided into two treatment groups, received continuous epidural infusion of 0.25% bupivacaine at a rate of 2-5 ml.hr(-1), or that of a combination of 0.125% or 0.25% bupivacaine and 0.0025% or 0.005% morphine at a rate of 2-4 ml.hr(-1). One, 4, 10, 16, 24 and 40 hr postoperatively, the following indices were measured: visual analogue scale score, modified Prince Henry pain scale score, arterial Pa(O)(2) and Pa(CO)(2), functional residual capacity (FRC), and tidal volume (TV). There was no difference in pain scores between the two groups except for significantly less pain at 40 hr in the combination group. Postoperative measurements of pulmonary function revealed a significant fall in Pa(O)(2), FRC and TV, indicating a reduction of 15-25% as compared with the preoperative values, and no significant differences between the two groups. The authors conclude that postoperative continuous epidural infusion of bupivacaine combined with morphine is highly effective in alleviating pain and improving pulmonary function in patients following USA.