British journal of anaesthesia
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Randomized Controlled Trial
Changes in the effect of propofol in response to altered plasma protein binding during normothermic cardiopulmonary bypass.
During normothermic cardiopulmonary bypass (CPB), the effect on propofol pharmacokinetics of changes in its binding to plasma proteins is consistent with the predictions of the well-stirred model of hepatic elimination for nonrestrictively cleared drug. However, whether changes in binding lead to clinically significant changes in the drug effect remains unclear. The purpose of this study was to assess changes in the drug effect of propofol in response to altered plasma binding using quantitative EEG measurements. ⋯ The anaesthetic effect of propofol significantly increased during CPB without any alteration in the total drug concentration. The enhanced efficacy may be caused by a reduction in plasma binding of the drug.
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Comparative Study
Ephedrine and phenylephrine for the treatment of maternal hypotension in a chronic sheep model of increased placental vascular resistance.
We hypothesized that ephedrine and phenylephrine are equal with respect to uterine and placental haemodynamics and fetal acid-base status after exposure to maternal hypoxaemia and hypotension in a chronic sheep model of increased placental vascular resistance (R(UA)). ⋯ In a chronic sheep model of increased placental vascular resistance, compared with ephedrine administration, phenylephrine administration was associated with impaired uterine and placental haemodynamics and increased fetal lactate concentrations.