Abstract 49: Optimal CPR Loop Duration for Asystole and Pulseless Electrical Activity During In-Hospital Cardiac Arrest
Background Cardiopulmonary resuscitation (CPR) is a process where time-cycled “loops” of chest compressions form the basis of action. Optimal loop duration is a compromise between interrupting compressions and detecting a change in the clinical state. Current CPR guidelines recommend a two-minute loop duration. The aim of this study was to investigate optimal loop duration in asystole (ASY) and pulseless electrical activity (PEA).
Material and methods Detailed defibrillator recordings from 261 in-hospital cardiac arrests at the University of Chicago Hospital (Chicago, Ill., U.S) and St.Olav University Hospital (Trondheim, Norway) were analyzed. The clinical states ASY, PEA, ventricular fibrillation/-tachycardia (VF/VT), return of spontaneous circulation, and death were annotated along the time axis. We analyzed the development of clinical states ASY and PEA, both as initial and secondary states. As the development of initial VF/VT depended on heterogeneous shock strategies implemented by providers, these patients (n=46) were excluded from further analysis.
Results The figure shows the development of PEA and ASY as Kaplan-Meier plots.ASY and PEA behaves similarly. By 5 minutes 50% percent of the patients with initial ASY/PEA have progressed to a different clinical state; by 8 minutes 25 % remain. Secondary ASY/PEA progresses earlier to other clinical states.
Discussion To minimize pauses in chest compressions it is reasonable to aim between the 50th and 25th percentile, when a change of state most likely has occurred. Optimal loop in initial PEA and asystole appears to be between 5 and 8 minutes, and between 1 and 3 minutes in secondary PEA and ASY.
- © 2011 by American Heart Association, Inc.