Comparisons of Myocardial Protective Effects of Sevoflurane at Different Concentrations against Ischemia in Isolated Rat Heart

Background: Sevoflurane, a newly developed halogenated inhalation anesthetic agent shows myocardial protective effects against global ischemia like other inhalation agents. We investigated differences between pharmacologic preconditioning effects at various concentrations of sevoflurane. Methods: Forty male Sprague-Dawley rats were subdivided into 4 groups (each n = 10). All groups underwent the same procedure (Langendorff preparation, 30 minutes ischemia and 60 minutes reperfusion) except for the concentrations of sevoflurane. The control group received no sevoflurane treatment. The sevo 1.6% group was given 1.6% sevoflurane before ischemia, the sevo 2.05% group was given 2.05% sevoflurane before ischemia, and the sevo 2.5% group was given 2.5% sevoflurane before ischemia. Hemodynamic parameters of all groups were recorded through a thin, saline-filled latex balloon and a transducer. Coronary flows were also measured. All hearts were stained by triphenyl tetrazolium to measure infarct size. Results: The sevoflurane administered groups showed higher left ventricular end systolic pressures and lower left ventricular end diastolic pressures than the control group after ischemia and reperfusion. The dP/ of the sevoflurane administration groups showed a more rapid recovery pattern after ischemia than the control. But no differences were found between the sevoflurane administered groups. Infarct sizes in the sevoflurane administered groups were smaller than those in the control group, and there were no significant differences between the sevoflurane administered groups. Conclusions: Sevoflurane (even below one MAC) administration before myocardial ischemia has a superb cardioprotective effects, i.e., rapid recovery of left ventricular fuctions, less stiffness development, and a reduced infarct size. There were no significant differences between the sevoflurane administered groups.