Increase in pre-shock pause caused by drug administration before defibrillation: An observational, full-scale simulation study

BackgroundThe importance of circulation during cardiopulmonary resuscitation has led to efforts to decrease time without chest compressions (“no-flow time”). The no-flow time from the interruption of chest compressions until defibrillation is referred to as the “pre-shock pause”. A shorter pre-shock pause increases the chance of successful defibrillation. It is unclear whether drug administration affects the length of the pre-shock pause. Our study compares pre-shock pause with and without drug administration in a full-scale simulation.MethodsThis was an observational study in an ambulance including 72 junior physicians and a cardiac arrest scenario. Data were extracted by reviewing video recordings of the resuscitation. Sequences including defibrillation and/or drug administration were identified and assigned to one out of four categories: Defibrillation only (DC-only) and drug administration just prior to defibrillation (Drug + DC) for which the pre-shock pause was calculated, and drug administration alone (Drug-only) for which pre-drug time was calculated.ResultsDC-only sequences were identified in 68/72 simulations, Drug + DC in 24/72, and Drug-only in 33/72. Median pre-shock pauses were 18 s (DC-only) and 32 (Drug + DC), and median pre-drug pause 6. The variation between pauses was statistically significant (p ≪ 0.001). DC-only and Drug + DC sequences was found in 22/72 simulations. A statistically significant difference of 8 s was found between the median pre-shock pauses: 17 s (DC-only) and 25 (Drug + DC) (p ≪ 0.001). For un-paired observations, the pre-shock pause increased with 78% and for paired observations 47%.ConclusionsDrug administration prior to defibrillation was associated with significant increases in pre-shock pauses in this full-scale simulation study.