AMINOPHYLLINE FAILS TO IMPROVE THE OUTCOME OF CARDIOPULMONARY-RESUSCITATION FROM PROLONGED VENTRICULAR-FIBRILLATION - A PLACEBO-CONTROLLED,RANDOMIZED, BLINDED EXPERIMENTAL-STUDY

Objectives. The purpose of this study was to evaluate systematically t he effects of the adenosine antagonist aminophylline on resuscitation outcome in a canine model of postcardioversion nonperfusing rhythm. Ba ckground. Theoretic considerations and experimental studies indicate t hat myocardial adenosine accumulation during prolonged ventricular fib rillation might play a significant role in postcardioversion asystole and electromechanical dissociation. A recent uncontrolled clinical tri al has suggested that the adenosine antagonist aminophylline might imp rove the outcome of cardiopulmonary resuscitation from refractory brad yasystolic cardiac arrest. Methods. Two placebo controlled, randomized , blinded experimental studies were performed. In protocol 1 (20 dogs) , ventricular fibrillation was induced and maintained for 7.5 min. Six ty seconds before cardioversion, dogs received 1 mg of epinephrine fol lowed by 250 mg of aminophylline or placebo. In protocol 2 (20 dogs), dogs were cardioverted to electromechanical dissociation after 5 min o f unsupported ventricular fibrillation. Sixty seconds later, all dogs received 1 mg of epinephrine followed by 250 mg of aminophylline or pl acebo. In both experiments, resuscitation efforts were continued until return of spontaneous circulation, of up to 30 min. The primary end p oint was survival to 1 h. Results. In protocol 1, 4 of 10 dogs survive d in the aminophylline group, whereas 7 of 10 dogs survived in the pla cebo group, a nonsignificant trend toward unfavorable outcome from ami nophylline. Pretreatment with aminophylline increased the number of ca rdioversion applications required to terminate ventricular fibrillatio n. In protocol 2, 5 of 10 and 6 of 10 dogs survived in the aminophylli ne and placebo groups, respectively. Conclusions. The results of this study suggest that aminophylline fails to improve the outcome of resus citation from prolonged ventricular fibrillation. It does not reverse established electrome chanical dissociation and may in fact increase t he number of cardioversion applications required to terminate ventricu lar fibrillation. The rationale for conducting clinical trials with am inophylline during cardiopulmonary resuscitation is questionable.