The postoperative analgesic efficacy of wound instillation with ropivacaine 0.1% versus ropivacaine 0.2%

Study Objectives: To assess the influence of ropivacaine concentration on wound. instillation-induced Postoperative analgesia following total abdominal hysterectomy with bilateral salpingo-oophorectomy. Design: Prospective, randomized. double-blind study. Setting: Large referral hospital. Patients: 40 ASA physical status I and II patients undergoing total abdominal hysterectomy with bilateral salpingo-oophorectomy. Interventions: A standard general anesthetic was administered. In all cases surgery was performed, via a Pfannenstiel incision. On completion of the surgery, a multi-orifice. 20-gauge epidural catheter was placed above the fascia such that the tip was sited at the point that demarcated 50% of the length of the surgical wound. Thereafter the cathether was connected to an electronic patient-controlled analgesia (PCA) device programmed to deliver 9 mL of drug with a lockout time of 60 minutes and no basal infusion. Patients were randomized to receive PCA with ropivocaine 0.1% (Group 0.1) or ropivacaine 0.2% (Group 0.2). During the first 6 postoperative hours. a co- investigator administered 16 rescue morphine (2 ma IV). Thereafter rescue meperidine 1 mg/kg was administered on patient request. Measurements and Main Results: The number of attempts to activate the PCA device and actual PCA instillations during the 24 hour shiny period were similar between the groups. The number of 2 mg rescue morphine dosages administered was 4.3 +/- 1.7 versus 4.4 +/- 2.5 for the Group 0.1 and Group 0.2. respectively. For Group 0.1 and Group 0.2, the total dose of rescue morphine administered during the first 6 postoperative hours was 8.7 mg +/- 3.6 versus 9.1 mg +/- 5 respectively. Rescue merperdine administration during the subsequent 18 hours was similar between the groups. Through-out the study period. pain scores were similar between the groups. Conclusion: With a pre-set volume. varying the concentration ropivacaine (0.1% versus 0.2 %) does not affect the analgesic efficacy of wound instillation following total abdominal hysterectomy with bilateral salpingo-oophorectomy. (C) 2004 by Elsevier Inc.