Canadian journal of anaesthesia = Journal canadien d'anesthésie
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The effect of increasing the concentration of sevoflurane anaesthesia on diaphragmatic function was investigated in six mechanically ventilated dogs. Diaphragmatic function was assessed by measuring the transdiaphragmatic pressure (Pdi) generated during bilateral supramaximal stimulation of the cervical phrenic nerves at frequencies of 0.5, 10, 20, 50, and 100 Hz under quasi-isometric conditions. Measurements were performed at 1, 1.5 and 2 MAC concentrations after maintaining stable conditions for one hour. ⋯ In addition, no change in Pdi during 10, 20, 50 Hz stimulation was noted at any of the three levels of anaesthesia. By contrast, Pdi with 100 Hz stimulation during 2 MAC sevoflurane exposure (28.1 +/- 5.0 cmH2O) decreased below Pdi levels seen at 1 and 1.5 MAC (35.3 +/- 4.3 cmH2O and 31.5 +/- 4.3 cmH2O, respectively) (P less than 0.05). From these results, we conclude that sevoflurane impairs diaphragmatic function in deep anaesthesia.
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Randomized Controlled Trial Comparative Study Clinical Trial
Post-caesarean section analgesia: a comparison of epidural butorphanol and morphine.
Epidural butorphanol 1, 2 and 4 mg were compared with morphine, 5 mg, for postoperative analgesia in 92 consenting, healthy, term parturients who had undergone Caesarean section under epidural lidocaine anaesthesia in a randomized double-blind study. Postoperative pain was assessed using a visual analogue scale and recorded with heart rate, blood pressure and respiratory rate. The demographic characteristics, and the incidences of primary and repeat Caesarean sections, were not different among the four treatment groups. ⋯ One of 69 patients (1.4 per cent) who received butorphanol developed pruritus compared with ten (43 per cent) of 23 patients who received morphine. The global assessments of the adequacy of analgesia were indistinguishable between morphine and butorphanol. Epidural butorphanol provides safe, effective postoperative analgesia, has a prompt onset, and a limited duration.
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Randomized Controlled Trial Clinical Trial
Antiemetic prophylaxis with promethazine or droperidol in paediatric outpatient strabismus surgery.
This randomized, double-blind study evaluated the antiemetic efficacy and the side-effects of promethazine pretreatment (0.5 mg.kg-1 IV + 0.5 mg.kg-1 IM) versus droperidol + placebo pretreatment (droperidol, 0.075 mg.kg-1 IV + physiological saline, 0.02 ml.kg-1 IM). One hundred unpremedicated ASA physical status I children ranging from two to ten years, and undergoing outpatient strabismus surgery were studied. All children received inhalational anaesthesia with halothane, nitrous oxide and oxygen. ⋯ Promethazine pretreatment is much less expensive than droperidol pretreatment. The incidence of restlessness was significantly less with droperidol (eight per cent) than with promethazine (36 per cent) (P less than 0.001). Promethazine pretreatment demands the use of an analgesic like acetaminophen in order to reduce the incidence of postoperative pain and restlessness.(ABSTRACT TRUNCATED AT 250 WORDS)
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The disposition of propofol was studied in women undergoing elective Caesarean section. Indices of maternal recovery and neonatal assessment were correlated with venous concentrations of propofol. After induction of anaesthesia with propofol 2.0 mg.kg-1, ten patients received propofol 6 mg.kg-1.hr-1 with nitrous oxide 50 per cent in oxygen (low group) and nine were given propofol 9 mg.kg-1.hr-1 with oxygen 100 per cent (high group). ⋯ The concentrations of propofol were similar between groups during the infusion but they declined at a faster rate in the low group postoperatively. Maternal recovery times did not depend on the total dose of propofol but the concentration of propofol at the time of eye opening was greater in the high group than the low group (1.74 +/- 0.51 vs 1.24 +/- 0.32 micrograms.ml-1, P less than 0.01). The rapid placental transfer of propofol during Caesarean section requires propofol infusions to be given cautiously, especially when induction to delivery times are long.
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The pharmacokinetics of alfentanil, 300 micrograms.kg-1 IV, were determined in patients undergoing elective abdominal aortic reconstruction. The mean age (+/- SD) of the patients was 64.3 +/- 7.4 yr; their mean weight was 74.7 +/- 13.8 kg. Five patients underwent aneurysm repair and six had aortobifemoral grafting. ⋯ There were no significant correlations between the pharmacokinetic variables and the duration of aortic cross-clamping, the duration of surgery, or the rate or total volume of IV fluids infused intraoperatively. In general surgical patients, the elimination half-time of alfentanil has been reported to be 1.2-2.0 hr. Although the elimination half-time of alfentanil was longer in patients undergoing abdominal aortic surgery, alfentanil was eliminated much faster than either fentanyl or sufentanil in this patient population.