British journal of anaesthesia
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Comparative Study
Haemodynamic effects of a prolonged infusion of propofol as a supplement to nitrous oxide anaesthesia. Studies in association with peripheral arterial surgery.
The haemodynamic effects of propofol at two infusion rates (54-65 and 108-130 micrograms kg-1 min-1) have been studied during peripheral arterial surgery in eight elderly patients premedicated with morphine sulphate 0.15 mg kg-1. The haemodynamic response to laryngoscopy and intubation was partially suppressed: neither arterial pressure nor heart rate exceeded awake values. ⋯ During surgery, with either spontaneous (SV) or intermittent positive pressure (IPPV) ventilation, both infusion rates were associated with decreases in arterial pressures when compared with the awake state. Cardiac output was decreased (SV: -35%, IPPV: -36%) and SVR increased (SV: +22%, IPPV: +45%) at the lower infusion rate; similar changes were observed during the faster infusion rate.
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Randomized Controlled Trial Clinical Trial
Onset and recovery of atracurium and suxamethonium-induced neuromuscular blockade with simultaneous train-of-four and single twitch stimulation.
Single twitch and train-of-four stimulation were applied at 0.08 Hz to each ulnar nerve and the force of contraction of the adductor pollicis was recorded during onset of and recovery from neuromuscular blockade by suxamethonium 1 mg kg-1 or atracurium 0.4 mg kg-1. Times to 90% first twitch blockade of train-of-four were (mean +/- SEM) 0.82 +/- 0.08 and 1.98 +/- 0.18 min for suxamethonium and atracurium, respectively, compared with times to 90% single twitch blockade of 1.00 +/- 0.07 and 3.35 +/- 0.37 min, respectively (P less than 0.05 in both cases). ⋯ The mode of stimulation had little effect on time to 10% recovery. The results are consistent with stimulation-induced augmentation in muscle blood flow, which increased delivery of the drug to the neuromuscular junction.
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Randomized Controlled Trial Clinical Trial
Atracurium, vecuronium and pancuronium in end-stage renal failure. Dose-response properties and interactions with azathioprine.
Dose-response relations for atracurium, vecuronium and pancuronium were determined in patients in end-stage renal failure for the initial neuromuscular blockade (using three cumulative doses) and for the maintenance of stable 90% response (during continuous infusion). All measurements were during renal transplant surgery, and the interaction of azathioprine on neuromuscular blockade was estimated. Mean ED95 doses were (microgram kg-1): atracurium 375.6, vecuronium 67.2, pancuronium 86.6; the initial blockade required significantly larger doses than in normal patients (37%, 20% and 45%, respectively, using ED50 values). ⋯ The atracurium dose was not influenced by renal function, whereas vecuronium and pancuronium requirements were significantly reduced by 23.2% and 61.5%, respectively, compared with normal patients (previous study). Azathioprine was injected at the rate of 1 mg kg-1 min-1 for 3 min at stable 90% neuromuscular blockade with constant-rate infusion of the neuromuscular blocking drug. This produced a relatively small and transient antagonism of blockade--probably of negligible clinical significance.
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Six unpremedicated patients who had given their informed consent were given vecuronium 0.08 mg kg-1 before elective surgery. Recovery from neuromuscular blockade was measured electrically and mechanically. Neuromuscular blockade was antagonized 1 h after the administration of vecuronium with two doses of neostigmine 2.5 mg (three patients) or edrophonium 0.5 mg kg-1 (three patients). ⋯ Recovery appeared to be faster in younger patients. Reintroduction of neuromuscular blockade occurred after the second dose of neostigmine 2.5 mg, given to antagonize the block. This did not occur after either dose of edrophonium 0.5 mg kg-1.