Remifentanil in Cardiac Surgery

Abstract

In response: We appreciate the opportunity to reply to the comments of Drs. Lehmann and Boldt regarding our article. Our study (1) differed from those published and quoted by them (2,3). The study involving patients with good left ventricular function scheduled for coronary artery bypass grafting analyzed data collected after induction of anesthesia with remifentanil and propofol and at various periods thereafter (2). Our study investigated the effect of boluses of remifentanil given to patients after they had achieved a steady state of anesthesia (with stable hemodynamics) and before any intervention such as endotracheal intubation. By starting data collection only after reaching the steady state, we suggest that the subsequent hemodynamic changes are as a result of the administration of remifentanil by bolus. Our study, therefore, investigated the effect of remifentanil boluses alone, without the confounding effects of other drugs (including premedicant drugs) or interventions and as such, it is difficult or impossible to compare the two studies. The second study quoted (3), performed in patients with poor left ventricular function, demonstrates the efficacy of a propofol-remifentanil technique in such difficult cases. However, the data presented in this study are not comparable to the data presented by us, as the study design and patient population are very different. Remifentanil infusions (without bolus administration) are used routinely and successfully in the authors’ unit as part of an anesthetic technique for patients undergoing all types of cardiac surgery and cardiac intervention, with the usual spectrum of left ventricular function. The findings of our study suggest that remifentanil should not, however, be given as a bolus dose at a rate greater than 0.33 μg · kg−1 · min−1 in such patients in the absence of surgical intervention. Peter Elliott MD, FRCA RK Mirakhur MD