Anaesthesia
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Randomized Controlled Trial Comparative Study Clinical Trial
Dose-response and minimum time to satisfactory intubation conditions after mivacurium in children.
We assessed neuromuscular blocking effects and tracheal intubation conditions following mivacurium in 121 anaesthetised children aged 1-10 years. The study was conducted in three parts. Parts 1 and 2 were undertaken during thiopentone-alfentanil-nitrous oxide anaesthesia; neuromuscular blockade was evaluated by recording the force of contraction of the adductor pollicis in response to train-of-four stimulation at 0.1 Hz. ⋯ The times to 90% and 100% depression of control twitch were 1.3 (0.3) and 1.9 (0.5) min; times to 5%, 25%, 75% and 90% recovery were 6.4 (1.0), 8.4 (1.1), 12.5 (1.1) and 14.4 (1.9) min, respectively. Intubation conditions were rated satisfactory in 33/50 children (0.66, 95% confidence interval 0.51-0.79) at 60 s and in 49/50 children (0.98, 95% confidence interval 0.89-1.0) at 90 s (p = 0.0001). Intubation conditions 90 s after mivacurium 0.2 mg.kg-1 were significantly better than those obtained in 10 patients given anaesthetic drugs alone (p = 0.002).
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This review summarises evidence for immunomodulatory effect of drugs administered peri-operatively. The clinical significance of the balance of pro- and anti-inflammatory cytokines may be seen in certain disease states, for example, meningococcal meningitis and Lyme arthritis. This balance may be altered peri-operatively. ⋯ Natural killer cell activity, which is involved in immunity against tumour cells and virally infected cells is transiently depressed by volatile anaesthetic agents and opioids. In contrast catecholamines enhance natural killer cell activity. Whereas decrease in immunoglobulin levels occur peri-operatively, this is not thought to be as a result of drugs at clinically used concentrations but rather due to haemodilution.
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Randomized Controlled Trial Clinical Trial
The haemodynamic effects of propofol in combination with ephedrine.
Forty ASA1 patients presenting for minor gynaecological surgery were randomly allocated into four study groups to compare the haemodynamic effects of adding different doses of ephedrine to an induction dose of propofol. Heart rate, oxygen saturation and non-invasive arterial blood pressure were monitored before and for 5 min after induction. In those patients who received propofol alone, there was a significant decrease in both systolic (p < 0.001) and diastolic (p = 0.003) blood pressure. ⋯ The addition of ephedrine 10 mg was insufficient to prevent hypotension. There was no significant effect on either heart rate or oxygen saturation in any group. We conclude that ephedrine may be safely employed to reduce the degree of hypotension during induction with propofol in this patient group.
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Comparative Study
The importance of the expiratory pause. Comparison of the Mapleson A, C and D breathing systems using a lung model.
A physical lung model simulating spontaneous respiration was used to investigate the influence of the respiratory pattern on the efficiency of the Mapleson A, C and D breathing systems. It is shown that the Mapleson A system is always the most efficient breathing system and that its performance is relatively independent of the respiratory pattern. When the expiratory pause is minimal, the Mapleson C system is almost as efficient as the Mapleson A, but becomes ever less efficient as the expiratory pause increases. ⋯ With a longer expiratory pause, this system's efficiency approaches that of the Mapleson A. The experimental results are compared with predictions generated by a mathematical model. There is good agreement between the two, validating the mathematics used.