COMPARISON OF THE EFFECTS OF INTRAPLEURAL BUPIVACAINE AND MORPHINE ON POST-THORACOTOMY PAIN.

BACKGROUND: Post-thoracotomy pain is the most severe types of postoperative pain. This study compares the effects of intrapleural bupivacaine and morphine on post-thoracotomy pain. METHODS: In a double blind clinical trial study, 30 patients candidate for unilateral thoracotomy were randomly divided into bupivacaine and morphine groups. Patients in the morphine group received 0.2 mg/kg morphine and those in the bupivacaine group received 1 mg/kg bupivacaine by an intrapleural catheter placed at the end of surgery by direct vision. Intrarpleural morphine and bupivacaine continued every 4 hours for the next 24 hours. If required, systemic analgesia with morphine (patient-controlled analgesia, PCA) also used as a postoperative analgesic. The amount of morphine consumption and level of postoperative pain at 2, 6, 12 and 24 hours after surgery were recorded. RESULTS: Patients did not differ significantly in terms of age, gender and duration of surgery. There were no significant differences between the two groups with regard to their mean score of pain at 2 and 6 hours of the surgery; however, the level of pain was significantly lower in the bupivacaine group compared to the morphine group at 12 and 24 hours of the surgery. In the bupivacaine group, the mean level of intravenous opioid used over the 24 hours following surgery was significantly lower than in the morphine group. DISCUSSION: Intrapleural injection of bupivacaine can be more effective in reducing post-thoracotomy pain compared to intrapleural morphine.

Preemptive analgesic effect of ketamine in patients undergoing elective cesarean section.

OBJECTIVES: In this study, the preemptive effect of a small dose of ketamine on postoperative wound pain and morphine consumption in patients undergoing elective cesarean section was evaluated. METHODS: In a randomized, double-blind clinical trial, 60 women with American Society of Anesthesiologists class I and II identification undergoing elective cesarean section were enrolled. In the case group, the patients received 0.5 mg/kg ketamine, and in the control group, they received isotonic saline, 5 minutes before the induction of anesthesia. Anesthesia was induced with 4 mg/kg thiopental followed by 1.5 mg/kg succinylcholine. A further neuromuscular block was achieved by using 0.2 mg/kg of atracurium. Anesthesia was maintained with nitrous oxide 50% and halothane in oxygen. The lungs were mechanically ventilated. After fetus delivery, fentanyl (2 microg/kg) and morphine (0.15 mg/kg) were given intravenously. In the postanesthesia care unit and in the ward, all patients received morphine. Pain was assessed by the Visual Analog Scales at 2, 6, 12, and 24 hours postoperatively; the amount of morphine used and side effects were recorded. RESULTS: There was no significant difference between the patients considering their operative details, homodynamic variables, side effects, and Apgar scores of their babies at first and fifth minutes. Significantly, lower amounts of morphine were used in the case group (4.8 mg+/-2.5 mg vs. 8.1 mg+/-4.2 mg) during the first 2 hours after surgery (P=0.01), but the difference was not significant during 2 to 24 hours (3.2+/-2.2 vs. 3.1+/-2.3). There were no statistical differences between the groups in pain 2, 6, 12, and 24 hours postoperatively. DISCUSSION: Intraoperative low-dose ketamine had no effect on morphine consumption during 2 to 24 hours after surgery. No significant differences were seen in the pain scores of the 2 groups during the study period. The preoperative administration of 0.5 mg/kg ketamine in patients undergoing cesarean section did not elicit a preemptive analgesic effect.