22

Abstract

Introduction: Advances in cardiopulmonary resuscitation (CPR) have focused on the generation and maintenance of adequate myocardial blood flow to optimize the return of spontaneous circulation and survival. Much of the morbidity associated with cardiac arrest survivors can be attributed to global brain hypoxic-ischemic injury. Methods: Fiber-optic intracranial pressure and brain tissue oxygen tension (PbtO2) probes were placed in the left frontal cortex prior to induction of VF. After 7 minutes of untreated VF, 3 month old female swine were randomized to receive one of three resuscitation strategies (N = 7 for each group): 1) Hemodynamic Directed Care (CPP-20): chest compressions (CCs) with depth titrated to a target systolic blood pressure of 100 mmHg and titration of vasopressors to maintain coronary perfusion pressures (CPP) > 20 mmHg; 2) Depth 33mm(D33): target CC depth of 33mm with standard ACLS epinephrine dosing; or 3) Depth 51mm(D51 – American Heart Association (AHA) optimal care): target CC depth of 51mm with standard ACLS epinephrine dosing. All animals received manual CPR guided by audiovisual feedback for 10 minutes before first shock. Differences in cerebral perfusion pressures (CerePP) and PbtO2 over time and between groups were evaluated using generalized estimating equations. Results: CerePPs were significantly higher in the CPP-20 group compared to both D33 (p<0.01) and D51 (p=0.046), and higher in survivors compared to non-survivors irrespective of treatment group (p<0.01). Only the CPP-20 group was able to consistently generate CerePPs above 30 mm Hg. PbtO2 was also higher in the CPP-20 group compared to both D33 (p<0.01) and D51 (p=0.013), and higher in survivors compared to non-survivors irrespective of treatment group (p<0.01). CPP and CerePP in the minute epoch immediately prior to defibrillation were well correlated across treatment groups and survival status (R2= 0.66). Conclusions: Hemodynamic directed resuscitation targeting CPPs > 20 mmHg following VF arrest produced cerebral perfusion pressures > 30 mm Hg and improved brain tissue oxygen tension compared to optimal AHA care