Dose-dependent effects of isoflurane on cardiovascular function in rats

ObjectivesIsoflurane is a widely used anesthetic in clinical practice and animal experiments. It exerts cardioprotective effects by pre- and postconditioning but also has dose-dependent cardiovascular side effects. In this article, we aim to characterize the hemodynamic effects of isoflurane.Materials and methodsWe used a pressure–volume catheter to evaluate the hemodynamic changes in adult Sprague–Dawley rats (n = 6) given increasing concentrations of inhaled isoflurane anesthesia. The concentration was started at 0.5% (baseline) and gradually increased. Data on cardiovascular variables were recorded at each concentration.ResultsHeart rate, blood pressure, and left ventricular systolic and diastolic function decreased as isoflurane concentration increased. At a concentration of 3%, isoflurane significantly decreased myocardial contractility, blood pressure, and heart rate, and impaired left ventricular diastolic function.ConclusionHigh-dose isoflurane resulted in unfavorable hemodynamics. Old age and dehydration may predispose animals to the unfavorable hemodynamic effects of isoflurane. Determining the optimal isoflurane concentration for anesthesia or preconditioning is important. The effects of isoflurane anesthesia on aged and/or volume-depleted animals should be further investigated.