[Pain Management, Local Infection, Satisfaction, Adverse Effects and Residual Pain after Major Open Abdominal Surgery: Epidural versus Continuous Wound Infusion (PAMA Trial)].

Introduction: The Management of postoperative pain after abdominal surgery is a major challenge to the anesthesiologist. The optimization of postoperative analgesia improves prognosis contributing also to patient satisfaction and reducing morbidity and mortality. The aim of this randomized control study is to perform the comparative analysis in terms of effectiveness of an unconventional and still poorly technique implemented, continuous wound infusion, and the currently most applied and gold standard technique, epidural analgesia, in the postoperative period after abdominal surgery.

Material And Methods: Fifty patients, previously subjected to abdominal surgery by median laparotomy with xifo-pubic incision were randomized to receive postoperative analgesia via epidural (n = 25) or via continuous wound infusion (n = 25) during 48 hours. The primary outcome was analysis of pain at rest (< 4/10 numerical pain scale) after 24 hours postoperatively. Scores of pain at six, 12 and 48 hours and three months after surgery were also evaluated, as well as the incidence of adverse effects 48 hours postoperatively.

Results: The proportion of patients with successful control of postoperative pain was 84% against 60% with epidural analgesia and continuous wound infusion, respectively. Within the continuous wound infusion group with uncontrolled pain, all patients rated the pain below 6/10 24 hours postoperatively. The incidence of nausea, vomiting, pruritus or íleus was lower in the continuous wound infusion group, with statistically significant results for recovery of intestinal function. There was one case of systemic local anesthetic toxicity with an episode of frequent ventricular extrasystoles without hemodynamic instability, which ceased after suspension of continuous epidural infusion of local anesthetic.

Discussion: This study suggests that continuous wound infusion is the technique with most efficacy and safety, being even better than epidural analgesia in postoperative pain control after major abdominal surgery. This technique is associated with better analgesia, lower incidence of side effects, high level of satisfaction and no residual pain, contributing to enhanced recovery.

Conclusion: Continuous wound infusion is an effective technique, which should be implemented for analgesia after major abdominal surgery, with advantages when compared with epidural analgesia, especially low incidence of adverse effects. Registration: Trial not registered.