Abstract 95: Early Administration of Epinephrine During Closed-Chest Resuscitation Fails to Improve Return of Spontaneous Circulation or Short-Term Survival
Introduction: Administration of epinephrine (EPI) during resuscitation from out-of-hospital VF is typically deferred until initial resuscitation efforts have failed.
Hypotheses: We hypothesized that early administration of EPI would favor higher return of spontaneous circulation (ROSC) and improve short-term survival (240 mins) as a result of promoting earlier increases in coronary perfusion pressure (CPP).
Methods: Three groups of 12 rats each underwent 10 mins of untreated VF followed by 8 mins of chest compression (CC) before attempting defibrillation. Rats were randomized to receive a bolus of EPI (0.02 mg/kg) into the right atrium immediately before CC (EPI0-min), at 3 mins of CC (EPI3-min), or at 6 mins of CC (EPI6-min). Depth of CC was titrated to maintain an aortic diastolic pressure between 26–28 mmHg in the absence of EPI and between 34–36 mmHg in the presence of EPI.
Results: The number of rats that achieved ROSC numerically decreased as the delay in EPI administration increased but the differences were not significant (EPI0-min, 11/12, 92%; EPI3-min, 10/12, 83%; EPI6-min, 8/12, 67%) despite succeeding in promoting early increases in CPP (Figure⇓). Likewise, no differences in short-term survival were observed.
Conclusions: Early administration of EPI failed to improve ROSC and short-term survival despite earlier increases in coronary perfusion pressure. These results suggest that favorable hemodynamic effects of early EPI administration (increases in CPP) could have been overshadowed by previously reported adverse effects of EPI on myocardial energy metabolism.