Shenfu injectio pretreatment reduces systemic toxicity of bupivacaine in pregnant rats / 中华麻醉学杂志

ABSTRACT

Objective To determine if pregnancy affects the toxicity of bupivacaine and to investigate the effect of Shenfu injectio,a preparation of Chinese herbal medicine,on central nervous system and cardiac toxicity of bupivacaine in pregnant rats.Methods Twenty-four SD rats weighing 320-360 g were assigned to 3 groups(n =8 each)Ⅰ non-pregnant control group,Ⅱ pregnant control group and Ⅲ Shenfu injectio pretreatment group. The animals were anesthetized with isoflorane(2%-4%)-O_2 inhalation which was stopped before bupivacaine infusion was started.Femoral artery was canunlated for MAP monitoring and blood sampling and femoral vein was cannulated for bupivacaine infusion.MAP,HR and ECG were continuously monitored.All animals in the 3 groups received continuous infusion of 5% bupivacaine at 2 mg?kg~(-1).min~(-1).In group Ⅲ Shenfu injectio 10 ml?kg~(-1) was injected intraperitoneally(IP)30 min before bupivacaine infusion whereas in the two control groups(group Ⅰ and Ⅱ)equal volume of normal saline was injected IP instead of Shenfu injectio.The duration between the beginning of bupivacaine infusion and onset of convulsion/arrhythmia(QRS≥90 ms)/asystol was recorded and the amount of bupivacaine infused was calculated.Results There was no significant difference in the amount of bupivacaine causing convulsion and asystol between group Ⅰ and Ⅱ but the amount of bupivacaine causing arrhythmia was significantly larger in group Ⅰ(non-pregnant) than in group Ⅱ(pregnant control group)(P＜0.05).The amount of bupivacaine causing convulsion,arrhythmia and asystole was significantly larger in Shenfu injectio pretreatment group(group Ⅲ)than in pregnant control group(group Ⅱ)(P＜0.05 or 0.01).Conclusion Bupivacaine- induced cardiotoxicity is increased in pregnant rats and Shenfu injectio pretreatment can reduce the systemic toxicity of bupivacaine in pregnant rats.