OBJECTIVETo observe the effects of electroacupuncture (EA) pretreatment at different times for heart arrest induced by bupivacaine poisoning in rats.

METHODSWith a randomized, blind, control study, 24 SD rats were divided into a control group, a EA for 60 min (EA 60) group and a EA for 30 min (EA 30) group, 8 cases in each one. Rats in the EA 60 group and EA 30 groups were treated with EA at bilateral "Neiguan" (PC 6), "Zusanli" (ST 36) and "Fenglong" (ST 40) for 60 min and 30 min respectively. While no treatment was given in the control group. Then rats were monitored by leadⅡelectrocardiograph; catheters were inserted into the femoral vein to open the vein access and into the carotis to monitor the arterial pressure. Three hours after EA, 10 mg/kg bupivacaine was injected through femoral vein. The mean arterial pressure (MAP) and heart rate (HR) were automatically recorded by PowerLab system. The time points when QRS widened by 20 percent and cardiac arrest and the survival rates were observed.

RESULTSAfter the injection of bupivacaine, five rats in the EA 60 group caught cardiac arrest,while all the rats in the other two groups caught it. The survival rates were not statistically significant among the three groups (>0.05). The time of QRS widening by 20 percent in the EA 60 group was (87.4±14.8) s,which was longer than (63.6±14.2) s in the EA 30 group and (51.2±12.4) s in the control group (both<0.05). From injection of bupivacaine to cardiac arrest, the time of (375.3±23.7) s in the EA 60 group and that of (328.3±47.7)s in the EA 30 group were more than (235.5±91.5) s in the control group (both<0.05). After the injection, MAP and HR in the EA 60 group were higher than those in the EA 30 group and control group at most time points (all<0.05).

CONCLUSIONSEA pretreatment apparently decreases the vulnerability of bupivacaine-induced heart arrest, with better protective effect of 60 min pretreatment than that of 30 min.