Abstract 17: A Noninvasive Method for Measuring the Physiologic Quality of CPR Through Application of Quantitative Waveform Analysis of the Ventricular Fibrillation Electrocardiogram
Background: Parameters by which the quality of cardiopulmonary resuscitation (CPR) is commonly gauged, include rate, depth, and chest compression fraction. These measure the process of delivering CPR but give no insight into its physiologic effect. Analysis of electrophysiologic changes during CPR may provide a direct assessment of the impact of CPR that transcends CPR process parameters.
Objective: Assess the relationship between coronary perfusion delivered over time (i.e., dose) during CPR and a quantitative measure of the ventricular fibrillation ECG, amplitude spectrum area (AMSA).
Methods: Data were pooled retrospectively from 3 swine resuscitation experiments, comprising 63 placebo study arm animals. Swine were sedated, anesthetized, and instrumented with micromanometer-tipped pressure catheters. Coronary perfusion pressure (CPP) was calculated as the difference between the aortic and right atrial pressures at the end of the diastolic phase. Ventricular fibrillation was induced with a transthoracic shock and left untreated for 5 or 8 minutes. CPR was then initiated and continued for 90 seconds (n = 14), 3 minutes (n=25), or 5 minutes (n=24), and was accompanied in 2 series by the administration of epinephrine, vasopressin, propranolol, and sodium bicarbonate. Coronary perfusion dosage was calculated as the area under the CPP curve (CPP-AUC), and AMSA measurements were taken from 5-second periods immediately prior to and immediately following CPR. Delta AMSA was calculated as the difference between the log of the ending and starting AMSA values. Linear regression was used to assess the association between CPP-AUC and Delta AMSA.
Results: In univariate models CPP-AUC was significantly inversely associated with Delta AMSA when duration of CPR was 3 minutes (p = 0.02) or 5 minutes (p = 0.002), but not 90 seconds (p = 0.119). In a multivariate linear regression model containing CPP-AUC, duration of CPR, and series, the CPP-AUC was significantly inversely related to Delta AMSA (p < 0.001).
Conclusion: The change in the VF waveform during CPR correlates strongly with the dose of perfusion provided over a period of CPR and thus may be a useful measure for estimating CPR quality independent of process measures.
- © 2011 by American Heart Association, Inc.