The comparison of pretreatment effect of 1% propofol and 20% ıntralipid on cardiotoxicity causing levobupivacaine plasma concentration ın rats

In this study, we aimed to investigate the effects of pretreatment with 1% Propofol and 20% Intralipid on levobupivacane plasma concentrations and cardiotoxicity in rats.Eighteen male Sprague-Dawley rats were divided into 3 groups in this controlled experimental study as; control (Group C, n=6), 1% Propofol (Group P, n=6) and 20% Intralipid (Group I, n=6).Control heart rate (HR) values of all animals were recorded after administrating im ketamine. Mechanical ventilation was started after performing tracheostomy. Baseline values of mean arterial pressure (MAP) and HR were recorded after cannulating abdominal artery for invasive monitorization. Femoral and tail veins were also cannulated for levobupivacaine infusion and fluid replacement, respectively. MAP and HR of all animals were recorded every 5 minutes during 20 minutes of intralipid and propofol pretreatment period. After 20 minutes of pretreatment period, infusion of 2 mg/kg/min levobupivacaine was started and maintained until asystole was observed. The following parameters were also recorded during levobupivacaine infusion: asystoly time, occurance of first dysryhtmia, the time of 25% and 50% reduction of HR and MAP and total levobupivacine dose. Intracardiac blood samples were collected and plasma levels of levobupivacaine was assessed. Kruskal-Wallis, Mann-Whitney U, Student?s t tests were used.Baseline values of HR and MAP were similar among the groups. The time to 50% decrease in HR and MAP, and the first dysrythmia time were significantly longer in Group I than in Groups P and C. As parallel to these findings, levobupivacaine doses which caused dysrtythmia and bradycardia were significantly higher in Group I than Groups P and C. Asystole time was significantly longer in Groups I and P than in Group C, while the total levobupivacaine dose was similar in Groups I and P. The plasma levobupivacaine levels were significantly lower in Groups I and P than in Group C.These findings showed that even though it is not as potent as 20% Intralipid, 10% intralipid containing propofol may delay the occurence of the cardiodepresive effects of levobupivacaine. Therefore, we believe that the protective effects of propofol in addition to its anesthetic effects may be beneficial during procedures having high risk for local anesthetic systemic toxicity such as regional anesthesia. Further investigations are also needed to support this hypothesis.Key words: levobupivacaine, 20% Intralipid, 1% Propofol, pretreatment, cardiotoxicity.