May 16, 2002

Effects of interrupting precordial compressions on the calculated probability of defibrillation success during out-of-hospital cardiac arrest

Trygve EftestølPetter A Steen


Cardiopulmonary resuscitation (CPR) creates artifacts on the ECG and, with automated defibrillators, a pause in CPR is mandatory during rhythm analysis. The rate of return of spontaneous circulation (ROSC) is reduced with increased duration of this hands-off interval in rats. We analyzed whether similar hands-off intervals in humans with ventricular fibrillation causes changes in the ECG predicting a lower probability of ROSC. The probability of ROSC after a shock was continually determined from ECG signal characteristics for up to 20 seconds of 634 such hands-off intervals in patients with ventricular fibrillation. In hands-off intervals with an initially high (40% to 100%) or median (25% to 40%) probability for ROSC, the probability was gradually reduced with time to a median of 8% to 11% after 20 seconds (P<0.001). In episodes with a low initial probability (0% to 25%; median, 5%), there was no further reduction with time. The interval between discontinuation of chest compressions and delivery of a shock should be kept as short as possible.

Mentioned in this Paper

Clinical Prediction Rule
Ventricular Fibrillation
Emergency Care
Basic Cardiac Life Support
Morphologic Artifacts
Anterior Thoracic Region
Fourier Transform
Electroversion Therapy

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