Comparison of the hemodynamic response to induction and intubation during a target-controlled infusion of propofol with 2 different pharmacokinetic models. A prospective randomized trial

Abstract

ObjectiveTo determine the best propofol pharmacokinetic model that meets patient requirements and is devoid of major haemodynamic side effects. Material and methodsProspective, randomised, open-label, clinical trial was performed on an intention to treat basis. It included 280 patients with ASA physical status I–III, aged 18–80 years and a weight range between 45 and 100kg, scheduled for surgery under general anaesthesia. They were randomised into two groups according to the pharmacokinetic model: Modified Marsh group and Schnider group. The haemodynamic changes that occurred during the induction and intubation were analysed. A propofol target-controlled infusion was started to achieve and maintain a bispectral index value between 35 and 55. At minute 6, orotracheal intubation was performed and the study finished at minute 11.Heart rate, mean arterial pressure and their product (HR×MAP) were measured and recorded every minute throughout the study. Every HR×MAP value was compared to its baseline value to determine the minimum value before intubation, the maximum value after intubation, the maximum variation after intubation, and its final value. The GRADIENTE (MIN, MAX) variable (primary endpoint of this study) analyses the difference between maximal and minimal values related to intubation. Propofol doses and calculated concentrations and any hypotensive events were also recorded. ResultsNo differences were found between groups regarding haemodynamic performance. GRADIENTE (MIN, MAX) values and the percentage of hypotensive events were: Modified Marsh group median 77.41% vs. Schnider group 84.86% (p=0.821) and 17.3% vs. 12.8% (p=0.292), respectively. ConclusionThe study failed to demonstrate any haemodynamic difference between the two groups, even though the Modified Marsh group received a larger dose of propofol.