Canadian journal of anaesthesia = Journal canadien d'anesthésie
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Two case reports have cited the recreational use of cocaine as possible trigger of a malignant hyperthermia (MH) crisis. We evaluated whether toxic concentrations of cocaine altered the in vitro muscle response to halothane during contracture tests for MH. Twenty-two patients were studied. ⋯ In contrast, in the presence of 1% halothane, MH-susceptible muscle showed either no change in contracture (six patients), an increase (two patients), or a decrease (two patients) when exposed to cocaine. However, the overall effect of cocaine on muscle contracture in the presence of 1% halothane was insignificant in both groups. We conclude that cocaine, even at toxic levels, does not have a direct effect on skeletal muscle contractility and thus is safe for MH-susceptible patients.
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Randomized Controlled Trial Clinical Trial
Preemptive opioid analgesia does not influence pain after abdominal hysterectomy.
Opioid administration before surgical stimulus may reduce or prevent subsequent pain. We studied the effect of timing of opioid administration on the pain-related behaviour after abdominal hysterectomy. Eighty-five patients scheduled for abdominal hysterectomy were blindly randomized to receive fentanyl 10 micrograms.kg-1 before induction of anaesthesia (FA), after peritoneal incision (FB) or after removal of the uterus (FC), or sufentanil 1 micrograms.kg-1 before induction of anaesthesia (SA) or after peritoneal incision (SB) respectively. ⋯ The times from skin closure to the first analgesic request did not differ among the five groups. The VAS scores using the two-way ANOVA with repeated measurements differed among the five groups (F = 4.046, df = 4, 213, P < 0.005). The VAS scores with one-way ANOVA differed among the five groups 30 min postoperatively (F = 4.542, df = 4, 58, P < 0.003), being higher in the FA (6.5 +/- 1.8) and SA (5.9 +/- 2.1) groups than in the FC (3.2 +/- 2.5) group, and at 120 min postoperatively (F = 3.217, df = 4, 18, P < 0.05), being higher in the FA than in the FB group (6.1 +/- 1.5 and 2.6 +/- 1.9 respectively).(ABSTRACT TRUNCATED AT 250 WORDS)
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Randomized Controlled Trial Clinical Trial
Quantifying the effect of enflurane on atracurium infusion requirements.
The present study was designed to evaluate the interaction between atracurium and enflurane in 40 adult surgical patients using closed-loop feedback control of infusions of atracurium. Anaesthesia was induced with thiopentone and fentanyl and intubation was facilitated with atracurium 0.5 mg.kg-1 lean body mass. During the first 90 min, anaesthesia was maintained with nitrous oxide in oxygen (2:1) and fentanyl. ⋯ Patient characteristics and controller performance, i.e., the ability of the controller to maintain the neuromuscular blockade constant at the setpoint, did not differ among groups. In Group II ISS decreased from 0.33 +/- 0.12 to 0.26 +/- 0.08 mg.kg-1.hr-1 (P < 0.01), in Group III from 0.32 +/- to 0.12 to 0.24 +/- 0.08 mg.kg-1.hr-1 (P < 0.001) and in Group IV from 0.29 +/- 0.09 to 0.21 +/- 0.09 mg.kg-1.hr-1 (P < 0.001). In the control group atracurium requirements remained unchanged throughout the study.(ABSTRACT TRUNCATED AT 250 WORDS)
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We have compared the dose requirements and recovery characteristics of a continuous mivacurium infusion given by the anaesthetist to maintain 95-100% block at the hand muscles with that of a surgeon-controlled, on-demand dosing technique based on the direct assessment of abdominal muscle tone during elective Caesarean section. Twenty-four full term pregnant patients were included. A rapid-sequence induction using thiopentone 3-5 mg.kg-1 and succinylcholine 1 mg.kg-1 was used. ⋯ The total doses of mivacurium (mean +/- SD) were 23.2 +/- 10.4 and 12.4 +/- 3.5 mg in the infusion and SCR groups, P < 0.01. On-demand, surgeon-controlled doses of mivacurium were injected at a mean of T1 42.3 +/- 36%. At the end of surgery, T1 and TOF ratio were respectively 16.7 +/- 13%, 5 +/- 10% and 48 +/- 37%, 30 +/- 24% in the infusion and SCR groups.(ABSTRACT TRUNCATED AT 250 WORDS)
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The influence of the level of experience of the laryngoscopist on the duration of laryngoscopy, the forces exerted on the tongue and on the maxillary incisors during laryngoscopy, were investigated. Five groups (anaesthetists, residents in anaesthesia, nurse anaesthetists, surgeons and medical students), each consisting of 15 individuals, participated in the study. An intubation manikin was used with a laryngoscope modified so that the forces applied during laryngoscopy could be measured. ⋯ The maximally applied forces on the tongue were 71.7 N, 60.5 N, 65.9 N, 74.2 N and 69.7 N, respectively. The maximally applied forces on the maxillary incisors were 49.9 N, 36.3 N, 41.1 N, 58.3 N and 53.9 N, respectively. These results indicate the level of experience has a significant influence on the duration of laryngoscopy but seems to have little influence on the forces applied to the tongue and the maxillary incisors.