Abstract P115: Higher Threshold and Dose of Coronary Perfusion Pressure are Associated with ROSC in Prolonged Swine Cardiac Arrest
Introduction: The amount of myocardial perfusion required for successful defibrillation after prolonged cardiac arrest is not known. Coronary perfusion pressure (CPP) is a surrogate for myocardial perfusion. One limited clinical study reported that a threshold of 15mmHg was necessary for return of spontaneous circulation (ROSC), and that CPP was predictive of ROSC. A distinction between threshold and dose of CPP has not been reported.
Hypothesis: Animals that achieve ROSC will have higher mean CPP and higher area under the CPP curve (AUC) than no-ROSC swine.
Methods: Data from 4 similar swine cardiac arrest studies were retrospectively pooled. Animals had undergone 8 –11 minutes of untreated ventricular fibrillation, 2 minutes of mechanical CPR, administration of drugs, and 3 more minutes of CPR prior to the first shock. Mean CPP ± standard error was derived from the last 20 compressions of each 30 second epoch of CPR and compared between ROSC/no-ROSC groups by RM-ANOVA. AUC for all compressions delivered over the 5 minutes was calculated by direct summation and compared by Kruskal-Wallis test. Prediction of ROSC was assessed by logistic regression.
Results: During 5 minutes of CPR (n=80), mean CPP ± SEM was higher in animals with ROSC (n=63) (p < 0.001). Animals with ROSC received more total flow than animals without ROSC (p < 0.001). Two regression models identified CPP (OR 1.11; 95% CI 1.05, 1.18) and AUC (OR 1.10; 95% CI 1.05, 1.16) as predictors of ROSC. Experimental protocol also predicted ROSC in each model (OR 1.70; 95% CI 1.15, 2.50) and (OR 1.59; 95% CI 1.12, 2.25), respectively.
Conclusion: Higher CPP threshold and dose are associated with and predictive of ROSC.