Abstract 320: Survival and Neurological Function With Rapid versus Delayed Automated Head-Up CPR in a Porcine Model of Prolonged Cardiac Arrest

Abstract

Background: Rapid Basic Life Support (BLS) treatment with controlled sequential elevation of the head and thorax, active compression-decompression CPR, and an impedance threshold device, collectively termed automated Head Up Position (AHUP)-CPR, is associated with better outcomes versus conventional CPR (C-CPR) in animal models and human observational studies. Hypothesis: Rapid AHUP-CPR should improve survival and neurological function vs rapid C-CPR followed by delayed AHUP-CPR. Aim: Determine if AHUP-CPR should be initiated as a BLS or ALS intervention. Methods: Male and female farm pigs (n=22) weighing~40kg were anesthetized and ventilated. Central venous and aortic pressures, as well as end-tidal CO2 (ETCO2) and cerebral oximetry (rSO2) were measured continuously. After 15 min of untreated VF, pigs were randomized to either rapid AHUP-CPR for 25 min or 10 min of C-CPR followed by 15 min of AHUP-CPR. Pigs received intravenous epinephrine and amiodarone after 24 min of CPR and were defibrillated 60 sec later. For the primary endpoint, 24-hour neurologic function, a veterinarian blinded to the CPR intervention assessed pigs using a Neurological Deficit Score (0 = normal and 260 = worst deficit score or death). Secondary outcomes included 24-hour survival rates and hemodynamic parameters. Data were expressed as mean ± SD. Statistical significance was determined by log-rank, Mann-Whitney-U and unpaired t-tests. Results: Sustained return of spontaneous circulation was achieved in 10/11 pigs with rapid AHUP-CPR vs 6/11 with delayed AHUP-CPR and cumulative 24-hour survival rates were 45.5% (5/11) vs 9.1% (1/11), respectively (p=0.01). Neurological Deficit Scores were 202.7 ± 80.3 with rapid AHUP-CPR vs 259.1 ± 3.0 with delayed AHUP-CPR group (p=0.04). Ten minutes after initiating CPR, ETCO2 (mmHg) was 45.0 ± 3.8 vs 26.9 ± 5.4 (p<0.001), and rSO2 (%) was 67.3 ± 3.9 vs 61.4 ± 6.3 (p=0.01) with rapid AHUP-CPR vs delayed AHUP, respectively. Conclusion: In a severe and prolonged model of porcine cardiac arrest, rapid AHUP-CPR, delivered as a BLS intervention, significantly improved the survival rate, neurological function and hemodynamics when compared with rapid C-CPR followed by delayed AHUP-CPR.