Hemodynamic effects of five different intravenous anesthetic agents during anesthesia induction. [Greek]
Authors: Dalakakis I, Fyntanidou B, Amaniti A, Kapanidis K, Lolakos K, ProvitsakiCh, Tsakiridou Ch, Grosomanidis V..
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Induction of anesthesia can be accomplished with intravenous or inhalational anesthetic agents, which have both desired and side effects. The aim of this study was to record, investigate and compare the hemodynamic profile of five different induction anesthetic agents in patients undergoing major vascular surgery. One hundred and fifty patients, who were scheduled for major vascular surgery, were randomly assigned into five groups according to the anesthetic agent that was used for anesthesia induction. The five agents used for anesthesia induction were: propofol [2mg/kg], thiopental [3mg/kg], etomidate [0.3mg/kg], midazolam [0.2mg/kg] and diazepam [0.3mg/kg]. Before induction of anesthesia patients were administered Ringer lactate to replace volume deficit due to preoperative fasting. Besides standard intraoperative monitoring, an arterial catheter and a pulmonary artery catheter were placed in all patients before anesthesia induction. Study parameters were either measured or calculated via algorithms and included: heart rate [HR], systolic, diastolic and mean systemic arterial blood pressure [SAPs, SAPd, SAPm], central venous pressure [CVP], right ventricle systolic and diastolic pressure [RVPs, RVPd], systolic, diastolic and mean pulmonary arterial pressure [PAPs, PAPd, PAPm], pulmonary artery occlusion pressure [PAOP], stroke volume [SV], cardiac output [CO], systemic and pulmonary vascular resistance [SVR, PVR]. Data were recorded before induction of anesthesia and 10min after intubation and initiation of mechanical ventilation. Data were compared both between groups and within groups for the two different phases of the study. There was no statistically significant difference between the groups in any of the recorded parameters at any phase of the study. On the contrary, comparison of the two study phases within groups revealed statistically significant differences in most of the recorded study parameters without any relation to the used anesthetic induction agent. HR, SAPs, SAPd, SAPm, SV and CO decreased statistically significant after anesthesia induction in all five groups. In contrast to that, CVP, RVPs, RVPd, PAPs, PAPd, PAPm and PAOP increased after anesthesia induction and initiation of mechanical ventilation. Administration of induction anesthetic agents and increase of intrathoracic pressures caused by initiation of mechanical ventilation had negative effects on patients hemodynamics, which however were not detrimental and cardiovascular stability was maintained in all patients during the study. Despite contradictory literature data, our study did not reveal any statistically significant difference between the five different anesthetic agents used for induction with regard to their hemodynamic effects. Replacement of volume deficit before induction of anesthesia, application of small tidal volumes and avoidance of high PEEP levels decreased any of the negative hemodynamic effects of anesthesia medications and mechanical ventilation. Based on the results of this study, it seems that in normovolemic patients, induction of anesthesia can be safe and without any significant hemodynamic effects regardless of the anesthetic agent used.