Abstract 170: Theoretical Model for Weighting Chest Compression Fraction During Cardiopulmonary Resuscitation

Background: The quality of cardiopulmonary resuscitation (CPR) is often measured by the metric of chest compression fraction, which has been associated with survival to hospital discharge. However, this metric may not provide the optimum information when analyzing the relationship between CPR quality and its effectiveness. Objective: We sought to demonstrate that a simple mathematical model that weights chest compression fraction by the chest compression rate would provide more textured and detailed information about CPR quality, with results that are disparate from unweighted measures. Methods: Using a hypothetical bout of CPR, we weighted the chest compression fraction by the chest compression rate (in beats/minute), incorporating periods of no CPR during which a patient might be moved or undergoing airway management. Different chest compression rates could represent different rescuers, or rescuer fatigue. These data can be captured with current defibrillator/monitor technologies. Results: Hypothetical Example: Consider a 16-minute period of resuscitation. Minutes 1-2: No chest compressions (2 min) Minutes 3-6: chest compressions (4 min) @ 100/min (Weight = 1) Minutes 7-8: No chest compressions (2 min) Minutes 9-11: chest compressions (3 min) @ 50 / min (Weight = 0.5) Minutes 12-13: No chest compressions (2 min) Minutes 14-16: chest compressions (3 min) @ 75 / min (Weight = 0.75) Chest compression Fraction = (4+3+3) / (2 + 4 + 2 + 3 + 2 + 3) = 0.63 Weighted Chest Compression Fraction = (4*1 + 3*0.5 + 3*0.75) / (2 + 4 + 2 + 3 + 2 + 3) = 0.48 Conclusion: In this theoretical example, the simple chest compression fraction (0.63) may overestimate the true quality of the CPR performed. The weighted measure value (0.48) may be a better indicator of the true quality of the CPR and may be useful in further differentiating CPR metrics.