Anaesthesia
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Randomized Controlled Trial
Induction of general anaesthesia by effect-site target-controlled infusion of propofol: influence of pharmacokinetic model and ke0 value.
We studied the use of a new ke0 value (0.6 min(-1)) for the Marsh pharmacokinetic model for propofol. Speed of induction and side-effects produced were compared with three other target-controlled infusion systems. ⋯ The Schnider model in effect-site control produced induction times that were longer (298 (282-398 [58-513])s) than those observed with the Marsh model in blood control (p < 0.05), or either effect-site control mode (p < 0.001). There were no differences in the magnitude of blood pressure changes or frequency of apnoea between groups.
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Autonomic function tests require standardised test conditions. We compared testing under non-standardised and standardised conditions and investigated the agreement between heart and pulse rate variability in 30 subjects with diabetes mellitus. Deep breathing, Valsalva manoeuvre and quick standing tests showed non-standardised reproducibility intraclass correlations (95% CI) of 0.96 (0.82-0.99), 0.96 (0.81-0.99) and 0.75 (-0.98 to 0.94), respectively. ⋯ Reproducibility under standardised conditions was comparable. The mean difference (95% limits of agreement) between heart and pulse rate variability was 0.99 (0.80-1.22) for very low frequency, 1.03 (0.88-1.21) for low frequency and 1.35 (0.84-2.16) for high frequency, with a Spearman's correlation coefficient of 1.00, 0.99 and 0.98, respectively. We demonstrated a high agreement between heart and pulse rate variability and acceptable reproducibility with most autonomic function tests, heart and pulse rate variability.