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Introduction: Comatose survivors of OHCA develop a post cardiac arrest syndrome (PCAS) characterized by myocardial dysfunction and cerebrovascular dysregulation. Hemodynamic derangements related to PCAS can jeopardize cerebral oxygen delivery and therefore impair neurologic recovery. However, optimal hemodynamic targets to ensure adequate cerebral oxygen delivery following OHCA remain undefined. Accordingly, we examined the relationship between cardiac index (CI), mean arterial pressure (MAP), and regional cerebral oxygen saturation (rO 2 %) following OHCA. Methods: CAPITAL-RETURN was a prospective, single-center observational study examining hemodynamics in comatose survivors of OHCA undergoing targeted temperature management after an initial shockable rhythm. Between August 2016 and December 2017, comatose survivors of OHCA underwent continuous, blinded, non-invasive monitoring of CI and rO 2 % using bioimpedance (Cheetah Medical, Portland, OR, USA) and near-infrared spectroscopy (Covidien, Boulder, CO, USA), respectively, for 96 hours after intensive care unit admission. In the present study, we examined the relationship between CI, MAP, and rO 2 % using multivariable linear regression. Results: In 56 patients in this analysis, the mean CI and MAP during the first 96 hours of intensive care unit admission were 3.2±0.5 L/min/m 2 and 76±6 mmHg, respectively (Figure). The mean rO 2 % was 63±9% and increased over time (+0.1% per hour; p2 % (+3.2% per L/min/m2 increase in CI; p2 % (p=0.42). After adjustment for MAP, the association between CI and rO 2 % remained significant (+3.1% per L/min/m2 increase in CI; p Conclusion: In comatose survivors of OHCA with an initial shockable rhythm, a higher CI is associated with improved rO 2 %. Further studies are needed to determine whether CI targets improve rO2% and neurologic outcomes following OHCA.

Introduction: Comatose survivors of out-of-hospital cardiac arrest (OHCA) have decreased cardiac index (CI) following return of spontaneous circulation. Although reversible, a reduced CI can contribute to cerebral hypoperfusion and impaired neurologic outcomes. We sought to examine the relationship between CI and clinical outcomes following OHCA. Methods: CAPITAL-RETURN was a prospective study examining hemodynamics in comatose survivors of OHCA undergoing targeted temperature management. Between August 2016 and December 2017, comatose survivors of OHCA with an initial shockable rhythm underwent continuous, blinded monitoring of CI using bioimpedance (Cheetah Medical, Portland, OR, USA) for 96 hours after intensive care unit (ICU) admission. In the present study, we examined the association between CI and the composite of death or severe neurologic dysfunction at 6 months (primary outcome) using logistic regression. Severe neurologic dysfunction was defined as a modified Rankin Scale score ≥4. We excluded patients who died or had withdrawal of advanced life support within 72 hours of ICU admission. Results: In 53 patients in this analysis (mean age 59±13 years, downtime 24±13 minutes, STEMI 35%), the rate of the primary outcome was 25%. The mean CI was lower in patients with (3.0±0.5 L/min/m 2 ) versus without (3.3±0.5 L/min/m 2 ) the primary outcome (p=0.018). A higher mean CI during the first 96 hours of ICU admission was associated with lower rates of the primary outcome (OR 0.85 per 0.1L/min/m 2 increase in CI; p=0.025). This association persisted after adjusting for age and downtime (OR 0.78 per 0.1L/min/m2 increase in CI; p=0.014). Cardiac index was similar in patients with versus without the primary outcome at the end of the 96-hour monitoring period (Figure). Conclusion: In comatose survivors of OHCA with an initial shockable rhythm, a higher CI during the first 96 hours of ICU admission is associated with lower rates of death or severe neurologic dysfunction.