Evaluation of early stage hemodynamic effect of levosimendan and dobutamine in rats with bupivacaine cardiotoxicity

Accidental intravasculer (IV) enjektion of local anesthetics may cause ventriculer tacikardi, ventriculer fibrilation, complete heatr block, asystolia and even death. Case reports of cardiac arrest resistant to cardiopulmoner resusitation after accidental IV enjection of local anesthetics has been reported the additive effect of levosimendan combined with dobutamine in a bupivacaine cardiotoxicity model.In the present study 28 Wistar Albino rat (250-300 gr) were used. Anesthesia was performed with intraperitoneal (İP) ürethane. Rats were ventilated with mechanical ventilator and arter canulations were performed for hemodynamic monitorisation. Intravenous 3 mg/kg/min bupivacaine infusion was started and when the symptoms of cardiotoxicity was observed the rats were divided into 4 groups. Grup B (Control group n:7): only 3 mg/kg/min IV bupivacaine infusion; Grup BL (n:7): after 12 microg/kg/min IV levosimendan in 10 minutes 0.3 microg/kg/min IV levosimendan infusion; Grup BD (n:7): levosimendan 3mcg/kg/min IV infusion after 12 microg/kg/min IV bolus combined with 3 microg/kg/min dobutamine infusion were administered. Bupivacaine infusion continued until asystolia occured. The duration of the study was limited to 120 minutes.There were no statistically significant difference between Group B and other study groups when first QRS change time, first arrhytmia time, arterial pH, pO2, pCO2 levels during the period of %50 decrease in mean arterial pressure and arterial pH and pCO2 levels during the period of %75 decrease in mean arterial pressure were assessed (p>0.05). Time to %50 and %75 decrease in mean arterial pressure was langer in Group BLD than the other groups; and there was statistically significant difference between Group B and Group BL, Group BD and Group BLD (p>0.05). Also time to %50 and %75 increase in heart rate was langer in Group BLD than the other groups. There was statistically significant difference when Group B was compared with Group BL, Group BD and Group BLD (p<0.05). In Group BLD where levosimendan was combined with dobutamine asystolia has not been observed in three rats.In conclusion this study showed that for bupivacaine induced myocardial depression treatment dobutamine was more effective than levosimendan nonetheless their combination has beter cardioprotective effects than these drugs solitory use.Key words: bupivacaine, cardiotoxicity, levosimendan,dobutamin, rat.