Abstract 210: Goal-Directed CPR is Less Effective With an Increased Interval From Cardiac Arrest Onset to Initiation of Chest Compressions

Abstract

Introduction: The interval from cardiac arrest (CA) to initiation of chest compressions (no-flow time) plays an important role in outcome of CA. The purpose of this study was to evaluate impact of no-flow time on the effectiveness of a goal-direct CPR strategy during prolonged cardiac arrest. Hypothesis: The effectiveness of goal-directed CPR declines with increased no-flow time. Methods: Porcine model of CA was utilized with a period of untreated ventricular fibrillation of 4 or 8 min (groups CA-4, CA-8, n=5/group) followed by a goal-directed CPR protocol for up to 40 minutes. Manual and mechanical chest compressions with impedance threshold device were used sequentially to achieve PetCO2 goal >20 mmHg. Epinephrine infusion and boluses were adjusted with the goal of achieving an arterial diastolic blood pressure >35 mmHg. Hemodynamic parameters were collected throughout the protocol, averaged in 5-minute intervals and compared between groups by an unpaired t-test. Results: A higher average DBP was achieved in the CA-4 vs. CA-8 group during CPR (19 ± 11 mmHg vs. 12 ± 9 mmHg: p<0.04) with stronger responses to epinephrine boluses (max increase 23 vs. 11 mmHg). Brain perfusion through internal carotid artery during CPR relative to baseline averaged 24 ± 34 % vs. 10 ± 12 % in the CA-4 vs. CA-8 group respectively (p<0.006). PetCO2 remained above 20 mmHg 71 ± 35 % vs. 31 ± 13 % of time during CPR in the CA-4 vs. CA-8 group respectively (p<0.001). Conclusion: In this swine model of prolonged VF cardiac arrest, increased no-flow time limits the effectiveness of a goal-directed CPR strategy. Moreover, the response to standard dose of epinephrine was higher after shorter no-flow time.