Abstract 305: Effect Of Initial Epinephrine Administration Time On Cerebral Perfusion In A Porcine Experimental Model Of Cardiac Arrest

Background: The effect of initial epinephrine administration time from cardiac arrest on cerebral perfusion pressure (CePP) during CPR is controversial. The purpose of this study was to evaluate the association between initial epinephrine administration time and CePP in a porcine cardiac arrest model. Methods: Initial administration time of epinephrine was divided into 3 groups based on time after inducing ventricular fibrillation (VF): 5 minutes (early group), 10 minutes (intermediate group), and 15 minutes (delayed group). Twenty-four pigs were randomly assigned to each group. After 4 minutes of untreated ventricular fibrillation, 2 cycles of BLS (BLS1 and BLS2 phase) and 10 cycles of ACLS (ACLS1~10 phase) were conducted. Macrovascular circulation (CePP) and microvascular circulation using laser doppler flowmetry presented as a fraction of the baseline flow (f-LDF) were measured. Linear mixed model was used to measure median difference in CePP and f-LDF between groups. Results: A total of 22 pigs were analyzed. Early group showed higher and earlier peak of CePP and f-LDF compared to those of intermediate or delayed groups. There was a significant group by phase interaction in CePP where the early group showed a higher CePP on earlier phase. (Early group: median 38.2 [95% confidence intervals 30.7-50.5] mmHg at BLS 2 phase, intermediate group: 27.1 [14.1-35.7] mmHg at ACLS1 phase, late group: 12.2 [2.2-34.9] mmHg at ACLS 4 phase), p< 0.001). There was no significant group by phase interaction in f-LDF; however, there was a tendency of decreased peak and delayed reach to peak with time. (Early group: median 5.7 [95% confidence interval 3.5-7.8] at ACLS 2 phase, intermediate group: 3.6 [1.5-5.1] at ACLS 4 phase, late group: 2.2 [0.9-3.3] at ACLS 6 phase, p =0.93). Conclusion: In this VF cardiac arrest porcine study, the early administration of epinephrine group showed higher and earlier peak of CePP and f-LDF compared to those of the intermediate and delayed groups.