Resuscitation of bupivacaine-induced cardiac arrest with lipid emulsion combined with epinephrine in rabbits

Objective To investigate the resuscitation of bupivacaine-induced cardiac arrest with lipid emulsion(LE)combined with epinephrine(EP)in rabbits.Methods Twenty-four male New Zealand rabbits weighing 2.0-2.5 kg were randomly divided into 4 groups(n = 6 each): group Ⅰ lactated Ringer's solution(LR); group Ⅱ LE; group Ⅲ LR+EP and group Ⅳ LE+EP.The animals were anesthetized with 20%urethane 1.0-1.2 g/kg,tracheostomized and mechanically ventilated(V_T 15-18 ml/kg,RR 40 bpm,FiO_2 100%).Right femoral artery was cannulated.ECG,MAP and P_(ET) CO_2 were continuously monitored.Thoracotomy was performed and heart was exposed.0.75% bupivacaine 10 mg/kg was infused iv over 6 min.At the end of bupivacaine infusion,LR and LE 8 ml/kg were infused over 10 min in group Ⅰ and Ⅱ respectively.A bolus of0.1% epinephrine 25 μg/kg was given iv followed by 0.1% EP infusion to maintain MAP at 80-90 mm Hg in addition to LR or LE infusion in group Ⅲ and Ⅳ.The amount of EP(in group Ⅲ and Ⅳ)and the outcome of resuscitation were recorded.Results Resuscitation failed in all animals in group Ⅰ and Ⅱ.Survival rate was significantly higher,survival time longer while the amount of EP was significantly lower in group Ⅳ than in groupⅢ.Conclusion Lipid emulsion increases the survival rate of resuscitation of bupivacaine-induced cardiac arrest in rabbits and reduces the amount of epinephrine needed. Key words: Fat emulsions,intravenous;  Epinephrine;  Bupivacaine;  Heart arrest;  Cardio-pulmonary resuscitation