Intraoperative infusion of dexmedetomidine reduces perioperative analgesic requirements.

PURPOSE: This prospective, randomized, double-blind study was designed to assess whether intraoperative infusion of dexmedetomidine provides effective postoperative analgesia. Postoperative pain scores and morphine consumption were compared in a treated group and a placebo group, both of which received patient-controlled morphine after total abdominal hysterectomy. METHODS: Fifty women were randomly assigned to two groups. Group D (n = 25) received a loading dose of dexmedetomidine 1 mug.kg(-1) iv during induction of anesthesia, followed by a continuous infusion at a rate of 0.5 mug.kg(-1).hr(-1) throughout the operation. Group P (n = 25) received a volume-matched bolus and infusion of placebo (0.9% saline). For each case, heart rate, peripheral oxygen saturation, and systolic and diastolic blood pressure were recorded intraoperatively and for 48 hr postoperatively. Patients used a patient-controlled analgesia device to receive bolus doses of morphine after surgery. Total morphine consumption, pain scores, and sedation scores were recorded for the first 48 hr (two hours in the postanesthesia care unit and 46 hr on the ward). RESULTS: The groups were similar with respect to mean times to extubation of the trachea. Pain and sedation scores were also similar between groups at all corresponding times throughout the 48-hr period of observation. Group D patients consumed significantly less morphine in the postanesthesia care unit and on the ward (P < 0.05 and P < 0.01, respectively). Fewer patients in Group D experienced itching or nausea/vomiting (P < 0.05). CONCLUSION: Continuous iv dexmedetomidine during abdominal surgery provides effective postoperative analgesia, and reduces postoperative morphine requirements without increasing the incidence of side effects.

Epidural neostigmine produces analgesia but also sedation in women after cesarean delivery.

BACKGROUND: Intrathecal neostigmine produces analgesia but also nausea, limiting its utility. In contrast, epidural administration of neostigmine has been suggested to produce postoperative analgesia without nausea in nonpregnant patients. The purpose of this study was to examine the dose range for efficacy and side effects of epidural neostigmine in women at cesarean delivery receiving combined spinal-epidural anesthesia. METHODS: After institutional approval and informed consent, 80 patients for elective cesarean delivery were given combined spinal-epidural anesthesia with 8 mg hyperbaric bupivacaine plus 10 microg fentanyl. Patients were randomized to receive either saline or 75, 150, or 300 microg neostigmine (n = 20 per group) in 10 ml saline after cord clamping. Pain, morphine consumption, and side effects were monitored for 24 h. RESULTS: Global pain assessment for the first 24 h was reduced from 5.4 +/- 0.2 in the saline group to 3.0-3.5 +/- 0.3 in the neostigmine groups, dose independently. Correspondingly, global satisfaction with neostigmine was also improved (P < 0.05). Nausea and morphine consumption were similar among groups. Intraoperative shivering and sedation were increased in the 300-microg neostigmine group only (P < 0.05), and postoperative sedation was increased by neostigmine in a dose-independent fashion (P < 0.05). CONCLUSIONS: Epidural neostigmine produced modest analgesia in women after cesarean delivery. In contrast with previous reports, which focused primarily on nausea, these data suggest that epidural neostigmine can also produce mild sedation for several hours. These data suggest a limited role for single bolus-administration epidural neostigmine for analgesia after cesarean delivery. They also support future study of epidural neostigmine for obstetric analgesia.