Effect of RapidShockTM Implementation on Perishock Pause in Out-of-Hospital Cardiac Arrest

Abstract

Objectives Shorter pauses in cardiopulmonary resuscitation (CPR) are associated with better health outcomes after out-of-hospital cardiac arrest (OHCA). Our primary objective was to examine the effect of a RapidShockTM defibrillator software upgrade compared with standard defibrillator software on the length of perishock pause during care for OHCA among adults. Secondary objectives were to assess the effects of RapidShockTM on other CPR pauses. Methods We conducted a retrospective cohort study between September 1, 2015 and September 30, 2020. “Standard” cardiac defibrillator software in manual interpretation mode was used for CPR delivered on or before November 30, 2018, while “RapidShockTM” software (ZOLL® Medical Corporation) was used after this date. For each study group, we calculated the perishock, perianalysis, and total CPR pause; each CPR cycle was considered an independent event. We then calculated the median and interquartile range (IQR) for observed pauses with the “Standard” and “RapidShockTM” software. Percent change in median perishock pause (shockable rhythms), perianalysis pause (non-shockable rhythms), and total CPR pause were compared between CPR administered with each software using the Mann–Whitney test. Results There were 733 and 782 distinct CPR cycles administered using “Standard” and “RapidShockTM” software, respectively. A 31.8% reduction in median perishock pause was observed with “RapidShockTM” software compared with the “Standard” software (22.0 s (IQR 18.0 − 27.0 s) vs. 15.0 s (IQR 13.0 − 19.0 s); p < 0.01). The decrease in median perishock pause was driven by a reduction in the preshock phase (18 s vs. 10 s; 44.4% decrease in median pause; p < 0.01). No differences were observed in median perianalysis pause between the two groups. When combining shockable and non-shockable rhythms, we observed a reduction of 23.5% in median CPR pause (17.0 s (IQR 11.0 − 24.0 s) vs. 13s (IQR 10.0 − 17.0 s); p < 0.01). Conclusions Overall, we observed that the use of “RapidShockTM” defibrillator software was associated with shorter CPR pauses compared with the “Standard” software. Additional studies are required to examine whether further reductions in CPR pauses may be achieved and to investigate associations between shorter CPR pauses and health outcomes.