SEVOFLURANE DEPRESSES MYOCARDIAL-CONTRACTILITY LESS-THAN HALOTHANE DURING INDUCTION OF ANESTHESIA IN CHILDREN

Background: Cardiovascular stability is an important prerequisite for any new volatile anesthetic, We compared echocardiographically derived indices of myocardial contractility during inhalation induction with sevoflurane and halothane in children. Methods: Twenty children were r andomized to receive either halothane or sevoflurane for inhalation in duction of anesthesia. No preoperative medications mere given, Myocard ial contractility was evaluated at baseline and at sevoflurane and hal othane end-tidal concentrations of 1.0 minimum alveolar concentration (MAC) and 1.5 MAC. Results: There were no differences between groups i n patient age, sex, physical status, weight, or height. Equilibration times and MAC multiples of sevoflurane and halothane were comparable. Vital signs remained stable throughout the study. Left ventricular end -systolic meridional wall stress increased with halothane but remained unchanged with sevoflurane. Systemic vascular resistance decreased fr om baseline to 1 MAC and 1.5 MAC with sevoflurane. Halothane depressed contractility as assessed by the stress-velocity index and stress-sho rtening index, whereas contractility remained within normal limits wit h sevoflurane. Total minute stress and normalized total mechanical ene rgy expenditure, measures of myocardial oxygen consumption, did not ch ange with either agent. Conclusions: Myocardial contractility was decr eased less during inhalation induction of anesthesia with sevoflurane compared with halothane in children. Although the induction of anesthe sia with sevoflurane or halothane mas equally well tolerated, the pres ervation of myocardial contractility with sevoflurane makes it an attr active alternative for inducing anesthesia in children.