Abstract 13786: Administration of β-Estradiol during Cardiac Resuscitation Fails to Improve Resuscitability and Survival in Male Sprague-Dawley Rats
Background: Administration of β-estradiol has been shown to improve left ventricle function yielding higher aortic pressure and cardiac index in rat models of trauma and hemorrhage. We hypothesized that similar effects could be elicited during resuscitation from cardiac arrest and investigated in a rat model of VF and closed chest resuscitation whether β-estradiol could improve resuscitability and survival.
Methods: VF was electrically induced in 18 male retired breeder Sprague-Dawley rats and left untreated for 8 minutes after which resuscitation was attempted by an 8 minute interval of chest compression and delivery of electrical shocks. Rats were randomized 1:1 to receive a bolus dose of β-estradiol 3,17-disulfate dipotassium salt (1 mg/kg) or 0.9% NaCl into the right atrium immediately before starting chest compression with the investigators blind to the assignment. Rats that restored spontaneous circulation were observed for a maximum of 180 minutes post-resuscitation.
Results: Cardiac activity - defined as the return of an organized electrical activity with an aortic pulse pressure >5 mmHg - was restored in 7 rats treated with β-estradiol but none of them survived the 180 minute post-resuscitation interval. In contrast, each of the 9 control rats restored cardiac activity and 3 survived the 180 minute post-resuscitation interval although the differences were not statistically significant (Figure). Myocardial and hemodynamic function measured at 60 minutes post-resuscitation in 3 remaining rats treated with β-estradiol and in 6 remaining controls was not different evidenced by comparable cardiac work index (18.2±3.1 vs 17.8±8.6 gm·m/kg; p=0.981), cardiac index (71±7 vs 70±30 l/min·kg-1; p=0.762), and mean aortic pressure (79±5 vs 77±18 mmHg; p=0.894).
Conclusions: β-estradiol failed to elicit favorable myocardial effects that could facilitate resuscitation and short-term survival in a male rat model of VF and closed chest resuscitation.
- © 2012 by American Heart Association, Inc.