British journal of anaesthesia
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Randomized Controlled Trial Clinical Trial
Interaction of magnesium sulphate with vecuronium-induced neuromuscular block.
We have investigated the interaction between magnesium sulphate 40 mg kg-1 i.v. and vecuronium. First, we determined the effect of pretreatment with magnesium on the potency of vecuronium using a single bolus dose-response technique. In addition, we compared the time course of vecuronium-induced neuromuscular block (vecuronium 100 micrograms kg-1) with and without magnesium pretreatment. ⋯ This was also true for the recovery index (20.1 (6.6) min vs 10.6 (3.4) min; P < 0.05) and duration to 75% recovery (63.4 (9.9) min vs 35.8 (6.9) min; P < 0.05). In the context of rapid sequence induction, pretreatment with MgSO4 improved the intubating score of vecuronium compared with vecuronium without MgSO4, reaching the same quality as that with suxamethonium 1 mg kg-1. We conclude that magnesium pretreatment increased the neuromuscular potency of vecuronium, in addition to modifying the time course of its neuromuscular block.
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We have studied the effect of renal function on the pharmacodynamics of mivacurium. Sixty patients were allocated to three groups according to creatinine clearance: group C (control), creatinine clearance > 50 ml min-1; group P (preterminal renal failure), creatinine clearance < 50 ml min-1 > 20 ml min-1; group T(terminal renal failure), creatinine clearance < 20 ml min-1. Neuromuscular transmission (train-of-four) was monitored using electromyography from the hypothenar muscle with stimulation of the ulnar nerve. ⋯ The dose of mivacurium necessary to maintain 95% neuromuscular block was similar in patients with normal renal function and patients with different levels of renal impairment. Recovery from neuromuscular block after ceasing mivacurium infusion was significantly prolonged in patients with preterminal renal impairment. There was a close correlation between mivacurium pharmacodynamics and pseudocholinesterase activity, but not creatinine clearance.
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Randomized Controlled Trial Comparative Study Clinical Trial
IV compared with brachial plexus infusion of butorphanol for postoperative analgesia.
In a randomized, double-blind, controlled study, we have compared two groups of patients receiving either continuous systemic i.v. or continuous brachial plexus infusion of butorphanol for analgesia after operations on the upper extremities. Twenty-two patients undergoing elective upper extremity surgery were allocated randomly to one of two groups to receive either butorphanol i.v. and saline injected into the brachial plexus sheath (i.v. group) or butorphanol injected into the brachial plexus sheath and saline i.v. (brachial plexus group). After surgery on the upper extremity under continuous axillary brachial plexus block, each patient received a continuous infusion of butorphanol either i.v. or into the brachial plexus sheath at a dose of 83.3 micrograms h-1. ⋯ From 9 h until 24 h after operation, pain scores were significantly higher in the i.v. group than in the brachial plexus group. The VAS score 9 h after operation was 3.3 (SD 2.7) in the i.v. group and 0.6 (0.9) in the brachial plexus group (P < 0.01); 12 h after operation 2.7 (1.8) in the i.v. group and 0.6 (0.9) in the brachial plexus group (P < 0.01); 18 h after operation 1.7 (1.0) in the i.v. group and 0.7 (1.0) in the brachial plexus group (P < 0.05); and 24 h after operation 3.2 (2.4) in the i.v. group and 0.7 (1.2) in the brachial plexus group (P < 0.01). We conclude that continuous injection of butorphanol into the brachial plexus sheath provided superior analgesia compared with continuous i.v. injection.
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Randomized Controlled Trial Clinical Trial
Is there any clinical advantage of increasing the pre-emptive dose of morphine or combining pre-incisional with postoperative morphine administration?
Pre-emptive treatment with an i.v. infusion of morphine 10 mg at induction reduces postoperative analgesic requirement and wound hypersensitivity compared with the same dose administered at the end of operation. Increasing the dose of preemptive morphine may potentially reduce postoperative pain further, while administering morphine at the end of operation, in addition to the beginning, may reduce pain generated by the sensory activity elicited from the wound in the immediate postoperative period. To examine this we have conducted a randomized, double-blind study in patients undergoing abdominal hysterectomy to compare the effect of morphine 20 mg administered before operation with 10 mg at induction and 10 mg on closure of the peritoneum. ⋯ Nausea and vomiting scores were higher in the 20-mg group. There was no significant difference between the two groups and neither regimen appeared to offer obvious clinical advantages compared with a lower dose (10 mg) morphine analgesic strategy. Therefore, there may be a ceiling effect to the production of pre-emptive analgesia by morphine.
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Randomized Controlled Trial Clinical Trial
Uptake of halothane and isoflurane by mother and baby during caesarean section.
Twenty-three patients undergoing Caesarean section received either 0.5% halothane or 0.8% isoflurane to supplement nitrous oxide-oxygen anaesthesia. We studied the rate of uptake of the agents by the mother and fetus by measuring partial pressures in maternal arterial (Pa) and fetal umbilical venous (Puv) blood. Mean induction-delivery interval did not differ between the halothane (10.8 min) and isoflurane (11.7 min) groups. ⋯ We conclude that both halothane and isoflurane are suitable agents for general anaesthesia for Caesarean section. The rate of uptake of isoflurane by the mother during Caesarean section was more rapid than halothane. The rate of uptake by the fetus from the mother was the same for halothane and isoflurane, so that fetal partial pressure as a fraction of the inspired partial pressure was greater for isoflurane than halothane.