Anesthesia and analgesia
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Anesthesia and analgesia · Jun 2003
Comparative StudyThe effects of enflurane, isoflurane, and intravenous anesthetics on rat diaphragmatic function and fatigability.
We examined the effect of isoflurane, enflurane, midazolam, ketamine, propofol, and thiopental on diaphragmatic functions under unfatigued and fatigued conditions in 228 rat isolated muscle strips. Diaphragmatic twitch characteristics and tetanic contractions were measured before and after muscle fatigue, which was induced by repetitive tetanic contraction with or without exposure to one of the anesthetics at clinically relevant plasma concentrations, and at 10 and 100 times this concentration, or at 1, 2, and 3 minimum alveolar anesthetic concentration (MAC). Isoflurane, midazolam, ketamine, propofol, and thiopental did not induce a direct inotropic or lusitropic effect under unfatigued and fatigued conditions. Enflurane did not change contraction or relaxation in fresh isolated diaphragm, but enflurane at 2-3 MAC enhanced diaphragmatic fatigability itself and fatigue-induced impairment of twitch characteristics and tetanic tensions. These effects were greater at 3 MAC than at 2 MAC. Our findings suggest that the reduction of diaphragm function previously reported in in vivo experiments using propofol, midazolam, and isoflurane is not related to a direct effect on intrinsic diaphragmatic contractility. Our results also indicate that large concentrations of enflurane may impair the diaphragmatic function at sites other than excitation-contraction coupling. ⋯ Enflurane did not change contraction or relaxation in fresh isolated rat diaphragm, but enhanced diaphragmatic fatigability itself and fatigue-induced impairment of twitch characteristics and tetanic tensions. Isoflurane, midazolam, ketamine, propofol, and thiopental had no direct effects on diaphragmatic functions under unfatigued and fatigued conditions. Isoflurane and these i.v. anesthetics may be advantageous over enflurane to anesthetize and/or sedate patients who are predisposed to diaphragmatic fatigue.
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Anesthesia and analgesia · Jun 2003
Comment Letter Case ReportsWas case report a case of unrecognized local anesthetic toxicity?
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Anesthesia and analgesia · Jun 2003
Randomized Controlled Trial Comparative Study Clinical TrialNalbuphine versus ondansetron for prevention of intrathecal morphine-induced pruritus after cesarean delivery.
In this prospective, randomized, double-blinded study, we compared the prophylactic efficacy of nalbuphine and ondansetron for the prevention of intrathecal morphine-induced pruritus after cesarean delivery. Two-hundred-forty parturients were randomly allocated into four groups. The N-4 group, O-4 group, O-8 group, and placebo group received IV 4 mg of nalbuphine, 4 mg of ondansetron, 8 mg of ondansetron, and 4 mL of normal saline, respectively, immediately after the baby was delivered. In the postanesthesia care unit, we found that the severity of pruritus score in the four groups was significantly different (P < 0.001). The prophylactic success rate for pruritus of the N-4, O-4, O-8, and placebo groups was 20%, 13%, 12%, and 6%, respectively (P < 0.001). The pruritus score between N-4 and placebo and O-4 and placebo was significantly different (P < 0.001 and P = 0.006, respectively). Treatment for pruritus was requested by patients in 25%, 47%, 51%, and 72% of patients in the N-4, O-4, O-8, and placebo groups, respectively (P < 0.001). There were no differences among groups in nausea/vomiting score, pain score, sedation score, or shivering score at 4, 8, and 24 h after surgery. Nalbuphine and ondansetron are more effective than placebo for the prevention of intrathecal morphine-induced pruritus after cesarean delivery. ⋯ Nalbuphine and ondansetron are more effective than placebo for the prevention of intrathecal morphine-induced pruritus after cesarean delivery.