We aim to elucidate the patterns of cerebral hemodynamics in the first 72 hours after ROSC. 

This is a neuromonitoring sub-study of the single-center prospective observational Early Neuroprognostication For Out-of-Hospital Cardiac Arrest (ENFORCE) study started in October, 2021. Consecutive, adult, comatose, OHCA patients of presumed cardiac etiology underwent TCD monitoring at least once within the first 72 hours post-ROSC using Dolphin 4D Viasonix. With constant mechanical ventilatory settings and continuous electrographic, pulse oximeter and end-tidal carbon dioxide detector monitoring, blood pressure was manipulated via vasopressors and cerebral autoregulation assessed by measuring cerebral blood flow velocities in response to change in mean arterial pressure. The primary outcome was neurological recovery at hospital discharge, defined as Cerebral Performance Category (CPC) of 1 or 2. 

Of the first 17 patients (median age 61 years, 95% males), 2 patients were excluded due to poor temporal window and hemodynamically unstable arrhythmia. We observe 4 unique patterns of cerebral hemodynamic responses after OHCA a) cerebral circulatory arrest (n=2), b) preserved autoregulation (n=8), c) loss of autoregulation (n=4) and d) cardio-cerebral asynchrony (n=1). Among two patients with loss of cerebral regulation, one had hyperemic flow, and another demonstrated high resistance flow. Majority (87.5%) with preserved autoregulation were discharged with CPC 1 or 2; those with the other hemodynamic responses had inpatient mortality (CPC 5).

We observed different cerebral hemodynamic responses in post-resuscitated OHCA that correlated with neurological outcomes. Further research is needed to assess if these hemodynamic responses could guide individualized management of resuscitated OHCA patients.