The differential neurologic prognosis of low-flow time according to the initial rhythm in patients who undergo extracorporeal cardiopulmonary resuscitation

Background: Limited data is available on the association between low-flow time and neurologic outcome according to the initial arrest rhythm in patients underwent extracorporeal cardiopulmonary resuscitation (ECPR). Methods: Between September 2004 and December 2018, 294 patients with in-hospital cardiac arrest (IHCA) were included in this analysis. We classified the patients into asystole (n=42), pulseless electrical activity (PEA, n=163) and shockable rhythm (n= 89) according to their initial rhythm. Primary outcome was poor neurologic outcome defined as Cerebral Performance Categories scores of 3, 4, and 5. Results: One-hundred ninety IHCA patients (64.6%) had poor neurologic outcomes. There was significantly worse neurologic outcomes among IHCA patients according to their initial rhythm (asystole [88.1%], PEA [66.3%], and shockable rhythm [50.6%], p < 0.001). The PEA group and the shockable rhythm group showed a significant association between low-flow time and neurologic outcomes while this relationship was not observed in the asystole group: PEA [rho=0.224, p= 0.005], shockable rhythm [rho= 0.298, p= 0.006]), and asystole [rho= 0.091, p= 0.590]. The best discriminative CPR to pumpon time for neurologic outcome was 22 min in the PEA group (area under the curve 0.687, 95% confidence interval [CI] 0.610-0.758, p < 0.001) and 46 min in the shockable rhythm group (area under the curve 0.671, 95% CI 0.593-0.743, p < 0.001). Conclusions: The effect of interplay between arrest rhythm and low-flow time might be helpful for decisions about team activation and management for ECPR and could provide information for early neurologic prognosis.