In a randomized, double-blind, placebo-controlled trial, we evaluated the use of preoperative local anesthesia with regard to postoperative pain. Before surgery in 66 patients scheduled for cholecystectomy, the abdominal wall along the proposed line of incision was infiltrated with 70 mL of 0.25% ropivacaine, 70 mL of 0.125% ropivacaine, or 70 mL of saline. Wound pain at rest, wound pain during mobilization, and pressure exerted to reach maximum pain tolerance were assessed after 6,26, 50, and 74 h and after 7 days. Consumption of analgesics was recorded. At the 6-h assessment, there was a statistically significant dose-related decrease in wound pain during mobilization (P = 0.001) and an increase of pressure exerted to reach maximum pain tolerance (P < 0.001). The tests were two-tailed and performed at a significance level of P < 0.05. There were no significant differences between the groups at later pain control assessments. The median time to first request for postoperative analgesics was significantly shorter (P = 0.014) in the saline group than in the ropivacaine 0.25% group. These effects are suggested to be a residual anesthetic effect of ropivacaine. The study gives no support to the hypothesis that preoperative local anesthetics dampen the inflammatory response and ensuing hyperalgesia.
Accepted for publication September 23, 1993.
© 1994 International Anesthesia Research Society