Prolonged continuous wound infusion of local anesthetic and steroid after major abdominal surgery to reduce opioid consumption: a randomized, double-blind trial

Background: Continuous wound infusion (CWI) is effective for post-operative pain management, but the effect of prolonged infusions and the use of steroids in the infused mixture have never been addressed. We investigate the effect of prolonged CWI with ropivacaine 0.2% (R) over 7 days and methylprednisolone (Mp) 1 mg/kg infused in the wound in the first 24 hours. Methods: This is a randomized, double blind, phase III trial (RCT) in major abdominal surgery with laparotomy. After a 24-hours pre-peritoneal CWI of R-Mp, patients were randomized to receive either R-Mp or placebo for the next 24 hours. Then, patient-controlled CWI with only ropivacaine 0.2% or placebo (according to the randomization group) was planned between 48 hours and 7 days after surgery. Morphine equivalents at 7 days were analyzed, together with any catheter- or drug-related side effect and PPSP at 3 months. Results: We enrolled 120 patients (63 in the CWI group, 57 in the placebo group). Prolonged CWI did not reduce opioid consumption in the first 7 postoperative days (P=0.08). CWI was associated with reduced consumption of non-opioid analgesics (P=0.03). Most of the patients continued to require bolus in the surgical wound beyond 48 hours. PPSP prevalence was not different between groups. Conclusions: Prolonged infusion with R-Mp is safe and effective but did not reduce opioid consumption in the 7 days after surgery or PPSP prevalence.