British journal of anaesthesia
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Comparative Study
Somatosensory and auditory evoked responses recorded simultaneously: differential effects of nitrous oxide and isoflurane.
Auditory (AER) and somatosensory evoked responses (SSER) were recorded simultaneously in eight patients under anaesthesia before surgery. We studied the effects of equi-MAC end-expiratory concentrations of isoflurane (0.65-0.75%) and nitrous oxide (60-65%). The anaesthetics were changed at random in three consecutive 10-min periods so that each patient received both drugs. ⋯ We were unable to demonstrate significant differences in Pa and Nb amplitude between isoflurane and nitrous oxide that we had seen previously. However, the amplitude of the SSER wave N20 was reduced significantly by nitrous oxide compared with isoflurane (P = 0.0004). This wave (N20) is thought to emanate from the thalamo-cortical radiations, and our findings may be explained by an analgesic effect of nitrous oxide mediated by endogenous opioids.
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Comparative Study
Effect of doxapram on the rate of recovery from atracurium and vecuronium neuromuscular block.
We have studied the effect of doxapram on the rates of spontaneous and neostigmine-induced recovery from neuromuscular block with atracurium and vecuronium, by measurement of the time to recovery of T1 (first twitch in the train-of-four) from 25 to 75% of control (recovery index, RI). After each neuromuscular blocking drug, RI was measured without administering either doxapram or neostigmine (control group), or after administration of doxapram 1 mg kg-1, neostigmine 50 micrograms kg-1 or a combination of doxapram and neostigmine, in groups of 10 patients. RI was significantly longer after vecuronium in the presence of doxapram compared with control (20.1 min vs 14.6 min). There was no significant difference in the RI after atracurium in the presence of doxapram compared with control (12.5 min vs 11.8 min) or when neostigmine was administered with or without doxapram (2.4 min vs 2.4 min, respectively after vecuronium; 3.3 min vs 2.9 min, respectively, after atracurium).
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Randomized Controlled Trial Multicenter Study Comparative Study Clinical Trial
Efficacy of orally administered ondansetron in the prevention of postoperative nausea and vomiting: a dose ranging study.
In a placebo-controlled, double-blind study, we have compared the efficacy of ondansetron 16 mg, 8 mg and 1 mg administered 8-hourly for prevention of postoperative nausea and vomiting. We studied 995 patients undergoing major gynaecological surgery; 982 were included in the analysis. ⋯ The frequency of nausea was 75%, 70%, 56% and 55% after placebo and ondansetron 1 mg, 8 mg and 16 mg, respectively; the corresponding frequencies of vomiting were 60%, 55%, 37% and 37%. Ondansetron 8 mg was as effective as 16 mg and both resulted in significant reductions in nausea and vomiting compared with placebo and ondansetron 1 mg (P less than 0.001).
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Randomized Controlled Trial Comparative Study Clinical Trial
Esmolol hydrochloride for management of the cardiovascular stress responses to laryngoscopy and tracheal intubation.
In a double-blind, randomized, controlled prospective study, 30 grade ASA I/II patients received a continuous i.v. infusion of normal saline or esmolol hydrochloride before induction of anaesthesia and tracheal intubation. Arterial pressure and heart rate were measured to assess the pressor response to laryngoscopy and intubation. The heart rate decreased in the esmolol group before induction of anaesthesia. The pressor response to laryngoscopy was significantly less marked in the esmolol group.