Postoperative pain after abdominal hysterectomy: a randomized, double-blind, controlled trial comparing continuous infusion vs patient-controlled intraperitoneal injection of local anaesthetic.

BACKGROUND: Local anaesthetics (LA) injected intraperitoneally have been found to decrease postoperative pain. This double-blind randomized study was performed comparing continuous infusion or patient-controlled intraperitoneal (i.p.) bolus injection of LA. The primary endpoint was supplemental opioid consumption during the first 24 postoperative hours. METHODS: Two multi-hole catheters were placed intraperitoneally at the end of the surgery in 40 patients undergoing elective abdominal hysterectomy. The patients were randomized into two groups: Group P: patients self-injected 10 ml of levobupivacaine 1.25 mg ml(-1) via the i.p. catheter as needed, maximum once per hour, and had continuous saline infusion 10 ml h(-1) into the second catheter. Group C: patients received a continuous infusion of 10 ml h(-1) of levobupivacaine 1.25 mg ml(-1) intraperitoneally through one catheter and 10 ml saline as bolus as needed via the other. Ketobemidone was administered intravenously as rescue medication. RESULTS: Total ketobemidone consumption during 0-24 h was lower in Group P compared with Group C (mean 23.1 vs 35.7 mg, P=0.04). No differences in the median pain scores were found between the groups. Earlier return of gastrointestinal (GI) function was found in Group P vs Group C (mean 1.5 vs 2.2 days, P<0.01), which also resulted in earlier home-readiness (mean 1.9 vs 2.7 days, P=0.04). CONCLUSIONS: A statistically significant opioid-sparing effect was found when patient-controlled levobupivacaine was administered intraperitoneally as needed compared with continuous infusion. This was associated with a faster return of GI function and home-readiness. There was, however, a wide confidence interval in the primary endpoint, opioid consumption.

A meta-analysis of the efficacy of wound catheters for post-operative pain management.

Local anesthetics (LA) are injected via catheters placed in surgical wounds for post-operative analgesia. The primary aim of this systematic review was to assess whether LA reduce pain intensity when injected via wound catheters. A literature search was performed from Medline via PubMed, EMBASE and the Cochrane database from 1966 until November 2009. The search strategy included the following key words: pain, postoperative, catheters and local anesthetics. Two co-authors independently read every article that was initially included and extracted data into a pre-defined study record form. A total of 753 studies primarily fit the search criteria and 163 were initially extracted. Of these, 32 studies were included in the meta-analysis. Wound catheters provided no significant analgesia at rest or on activity, except in patients undergoing gynecological and obstetric surgery at 48 h (P=0.03). The overall morphine consumption was lower (≈13 mg) during 0-24 h (P<0.001) in these patients. No significant differences in side effects were found, except for a lower risk of wound breakdown (P=0.048) and a shorter length of hospital stay (P=0.04) in patients receiving LA. A statistically significant heterogeneity was seen between the studies in most end-points. LA injected via wound catheters did not reduce pain intensity, except at 48 h in a subgroup of patients undergoing obstetric and gynecological surgery. Rescue analgesic consumption was also lower in this group at 0-24 h. The magnitude of these effects was small and compounded by pronounced heterogeneity.