Effect of maintenance bolus on the recovery profile of a short-acting nondepolarizing muscle relaxant.

STUDY OBJECTIVE: To evaluate the effect of different maintenance boluses of a short-acting nondepolarizing neuromuscular blocking drug on its spontaneous recovery profile during anesthesia. DESIGN: Prospective, randomized, double-blind, dose-ranging study. SETTING: University-based medical center. PATIENTS: 69 ASA physical status I and II consenting adult outpatients undergoing general anesthesia with an anticipated duration of at least 2 hours. INTERVENTIONS: Patients were randomized to one of three study groups. Following induction of anesthesia with propofol and fentanyl, rapacuronium 1.5 mg x kg(-1) intravenously (i.v.), was administered to facilitate tracheal intubation. Anesthesia was maintained with desflurane 4% end-tidal in combination with nitrous oxide 67% in oxygen. When the first twitch (T(1)) in the train-of-four (TOF) returned to 25% of its baseline value, a maintenance dose of rapacuronium 0.25 mg x kg(-1) i.v. (Group 1), 0.5 mg. kg(-1) i.v. (Group 2), or 0.75 mg. kg(-1) i.v. (Group 3) was administered. The time course of neuromuscular block was monitored at the wrist using standard electromyography. MEASUREMENTS AND MAIN RESULTS: The times for recovery of the T(1) to 25% of the baseline value following different maintenance doses of rapacuronium were only 6.3 +/- 2.2, 7.5 +/- 2.3, and 9.6 +/- 2.5 minutes, in Groups 1, 2 and 3, respectively. However, the times for the TOF ratio to return to 0.7 were 44 +/- 15, 53 +/- 20, and 66 +/- 30 minutes in Groups 1, 2, and 3, respectively. Although recovery times were significantly longer after rapacuronium 0.75 mg x kg(-1) i.v. (Group 3), there were no significant differences in any of the recovery variables between Groups 1 and 2. CONCLUSIONS: Spontaneous recovery of the T(1) to 25% of the baseline value occurred 6 to 10 minutes after a maintenance bolus dose of rapacuronium 0.25 to 0.75 mg x kg(-1) i.v. However, recovery to a TOF>0.7 required 44 to 66 minutes during desflurane anesthesia.

Effect of parecoxib, a novel intravenous cyclooxygenase type-2 inhibitor, on the postoperative opioid requirement and quality of pain control.

BACKGROUND: The analgesic efficacy and side effect profile of intravenous parecoxib, a novel cyclooxygenase type-2 (COX-2) inhibitor, was assessed in a double-blinded, placebo-controlled study involving patients undergoing major gynecologic surgical procedures. METHODS: After Institutional Review Board approval, 60 consenting women, American Society of Anesthesiologists (ASA) physical status I-III, undergoing lower abdominal surgery with a standardized general anesthetic technique were randomly assigned to receive one of three study medications: group 1 (control) received normal saline; group 2 received intravenous parecoxib, 20 mg; and group 3 received intravenous parecoxib, 40 mg. The initial dose of study medication was administered when the patient first requested pain medication after surgery. All patients had access to patient-controlled analgesia (PCA) with intravenous morphine, 1 or 2 mg, with a 6-min lockout period. Subsequent doses of the same study medication were administered at 12-h and 24-h intervals after the initial dose. The postoperative opioid analgesic requirement (PCA morphine usage), pain scores, pain relief scores, side effects, and need for supplemental medications (e.g., antiemetics, antipruritics, laxatives) were recorded. RESULTS: Compared with saline, intravenous parecoxib, 20 mg and 40 mg every 12 h, significantly decreased the PCA morphine usage during the first 6 h postoperatively (group 1, 25 +/- 13 mg; group 2, 16 +/- 11 mg; group 3, 17 +/- 10 mg) and at 12 h (group 1, 34 +/- 18 mg; group 2, 24 +/- 14 mg; group 3, 23 +/- 13 mg) and 24 h (group 1, 51 +/- 27 mg; group 2, 34 +/- 20 mg; group 3, 33 +/- 21 mg) after surgery. However, there were no significant differences in the patients' global evaluation of the study medications at 12 h and 24 h between those who received intravenous parecoxib (20 or 40 mg) and saline. Moreover, the postoperative pain scores and side effect profiles were similar in the three treatment groups. CONCLUSION: Intravenous parecoxib (20 or 40 mg) was effective in decreasing the PCA opioid requirement after lower abdominal surgical procedures. However, it failed to improve pain management or reduce opioid-related side effects in the early postoperative period.