[The effect of ventricular fibrillation time and NYHA classification on defibrillation in intensive care unit patients].

OBJECTIVE

To investigate whether the sequence of defibrillation (DF) and cardiopulmonary resuscitation (CPR), duration of ventricular fibrillation (VF), and New York Heart Association (NYHA) classification would affect DF result in intensive care unit.

METHODS

Ninety-three cases needing instantaneous DF were divided into three groups according to VF lasting time: <4 minute group (n=53), 4 - 8 minute group (n=24), >8 minute group (n=16), and each group was randomly divided into two sub-groups according to time sequence: the prior DF group or the prior CPR for five cycles followed by DF group (prior CPR group). The effect of VF time, the sequence of DF and CPR, and NYHA classification on success rate of DF were observed.

RESULTS

With prolonging VF time, success rate of DF obviously lowered [success rate of DF for VF<4 minute, 4 - 8 minute, and >8 minute groups were 83.0% (44/53), 62.5% (15/24), and 25.0% (4/16), respectively, all P<0.01]. When VF time lasted less than 4 minutes, success rate of DF in the prior DF group was obviously higher than that in the prior CPR group [88.9% (24/27) vs. 76.9% (20/26), P<0.05]. When VF time lasted for 4 - 8 minutes, the prior DF group had slightly higher success rate of DF compared with the prior CPR group [66.7% (8/12) vs. 58.3% (7/12), P=0.09]. When VF time lasted longer than 8 minutes, the success rate of DF in the prior CPR group was obviously higher than that in the prior DF group [37.5% (3/8) vs. 12.5% (1/8), P<0.01]. The success rate of DF was lowered in higher NYHA classification [success rate of DF for NYHA classification I-IV was 96.4% (27/28), 80.0% (20/25), 47.8% (11/23), 29.4% (5/17), respectively, P<0.05 or P<0.01].

CONCLUSIONS

VF lasting time and NYHA classification are key factors to success rate of DF, and the choice of sequence of DF and CPR depends on the lasting time of VF. For cases with the high NYHA classification, we should make some judgement beforehand and prepare some preventive measures.