Abstract 277: Neurologically Intact Survival and Time Interval From Collapse to Return of Spontaneous Circulation for Out-of-Hospital Non-Shockable Cardiac Arrest; A Comparison of Pulseless Electrical Activity and Asystole

Background: Early achievement of return of spontaneous circulation (ROSC) after cardiac arrest is critical to neurologically intact survival, but few data are available concerning this interval comparing pulseless electrical activity (PEA) and asystole. Methods: From the All-Japan Utstein Registry, a prospective, nationwide, population-based registry of out-of-hospital cardiac arrest (OHCA) between 2005 and 2011, we included adult patients who received resuscitation care after witnessed OHCA due to non-shockable arrest and whose ROSC was achieved before hospital arrival. We divided study patients into two groups according to the initial cardiac arrest rhythm and evaluated the relationship between the collapse-to-ROSC interval and favorable neurological outcome 30 days after cardiac arrest. Results: Of the 31,845 patients who achieved ROSC after witnessed OHCA, 12,905 (40.8%) achieved ROSC after PEA and 7,259 (22.8%) after asystole. The PEA group had a significantly shorter collapse-to-ROSC interval compared with the asystole group (18.9±11.6 vs. 25.3±12.6 minutes, p<0.0001) and a significantly higher frequency of 30-day favorable neurological outcome (15.5% vs. 7.1%, p<0.0001). After adjustment for resuscitation, the likelihood of favorable neurological outcome decreased for every 1 minute increment in the collapse-to-ROSC interval in the PEA group (adjusted OR; 0.94, 95% CI, 0.93 to 0.95) and in the asystole group (adjusted OR; 0.93, 95% CI, 0.91 to 0.94). Non-linear regression analysis showed that frequency of favorable neurological outcome decreased from 33.6% to 0% for every minute that passed between collapse and ROSC in the PEA group and from 29.2% to 0% in the asystole group. For favorable neurological outcome, a collapse-to-ROSC interval of 56.5 minutes had a sensitivity of 100% with a negative predictive value of 99.6% in the PEA group, and that of 56.5 minutes had a sensitivity of 100% with a negative predictive value of 99.1% in the asystole group. Conclusion: In patients achieving ROSC after witnessed OHCA, PEA patients had a significantly higher favorable neurological outcome than asystole patients. However, the interval in which resuscitation efforts must be sustained is similar for both arrest rhythms.