Evaluation of bupivacaine nerve blocks in the modification of pain and pulmonary function changes after thoracotomy.

Thirty-one patients undergoing thoracotomy were prospectively randomized to receive (1) no nerve blocks (n = 12), (2) placement of percutaneous catheters for intermittent nerve blocks with bupivacaine (Marcaine) (n = 10), or (3) bupivacaine nerve blocks intraoperatively (n = 8). One patient refused postoperative evaluation and was not included in this study. All patients received similar preoperative, intraoperative, and postoperative medications. Comparison of preoperative and postoperative arterial blood gases, assessments of pain and alertness, and chest roentgenograms showed no statistical advantage for any group. Analgesic requirements and pulmonary functions (functional residual capacity, tidal volume, minute ventilation peak flow, or forced expiratory volume) did not differ among the groups. Statistically significant differences were seen in mean respiratory rate and forced vital capacity. These differences, however, indicate that bupivacaine either by intraoperative use or by intermittent percutaneous administration did not improve postoperative increases in respiratory rate or decreases in forced vital capacity.