ANALGESIA AFTER LAPAROSCOPIC CHOLECYSTECT OMY USING INTRAPERITONEAL BUPIVACAINE

Objectives: The aims of this study were to assess the analgesic effect of the intraperitoneal topical administration of 0.375% bupivacaine i n patients undergoing laparoscopic cholecystectomy and to carry out a pharmacokinetic study of bupivacaine administered topically by intrape ritoneal route. Study design: Randomized, double-blind controlled tria l. Patients and methods: Twenty-four patients of ASA physical status 1 or 2, undergoing elective laparoscopic cholecystectomy, were included . Anaesthesia technique was the same for all patients. At the end of s urgery, they were randomly assigned to one of two groups. Patients in group bupivacaine were administered 0.375% bupivacaine, 0.6 mL . kg(-1 ) intraperitoneally in both subdiaphragmatic areas and the cholecystec tomy wound, those of the control group were given tile same volume of NaCl 0.9%. Analgesia was provided by morphine PCA. Postoperative pain, assessed on a 100 mm visual analogue pain scale (VAS), and administer ed morphine were recorded 30 min after extubation, and 0.5, 1, 2, 3, 6 , 12, 24, 36 and 48 hours later. Blood samples were collected 2, 5, 15 , 30, 60, 90, 120, 180, 300 and 480 min after the intraperitoneal admi nistration of bupivacaine to measure bupivacaine plasma concentration. Statistics included Student ttest and Chi square test. P<0.05 was con sidered significant. Results: There was no significant difference betw een the two groups with regard to VAS scores during the first 48 posto perative hours. Morphine requirements (total and at each point) were a lso similar. Plasma bupivacaine concentrations reached a plateau at 10 -20 min, and then decreased slowly. The median plasma peak concentrati on was 0.94 +/- 0.47 mu g . mL(-1). In one patient toxic concentration s (> 1.6 mu g . mL(-1)) during the first 60 min after intraperitoneal administration were obtained, while in another patient a concentration of 1,58 mu g . mL(-1) was reached twice. Conclusions: Intraperitoneal administration of 0.6 mL . kg(-1) of 0.375% bupivacaine is ineffectiv e in reducing postoperative pain after laparoscopic cholecystectomy. F urthermore these high doses of bupivacaine may result in toxic plasma concentrations. This technique is not safe and cannot be recommended.