Abstract 135: Identifying Optimal Mean Arterial Pressure in Cardiac Arrest Patients: Are Precision Medicine Approaches Feasible?

Abstract

Introduction: Loss of cerebral autoregulation after cardiac arrest (CA) is associated with worse outcomes. A population-based mean arterial pressure (MAP) threshold, such as a post-resuscitation goal of ≥ 65 mmHg, may be insufficient to account for patient-specific factors, like autoregulatory failure. We investigated the feasibility of determining optimal MAP (MAP OPT ) using regional cerebral tissue oxygen monitoring with near-infrared spectroscopy (NIRS). Hypothesis: Autoregulatory failure and MAP OPT can be identified in individual patients after CA. Methods: We prospectively enrolled adult comatose CA survivors undergoing invasive MAP and regional cerebral oxygen monitoring with NIRS in an ICU between April 2022 and May 2023. Tissue oxygenation autoregulatory index (TOx) was derived using a moving Pearson correlation coefficient of 30 consecutive, 10-second averaged values of MAP and tissue oxygen index signals. TOx ≥ 0.3 defined impaired autoregulation. MAP values were divided into bins of 5 mmHg for which each corresponding TOx was averaged. Parabolic curve fitting determined the MAP value with the lowest associated TOx value (MAP OPT ). Results: Of 35 patients enrolled, 74.3% experienced out-of-hospital cardiac arrest with a mean (SD) age of 55.0 (13.9) years. Six (17.1%) patients survived to hospital discharge and 4 (11.4%) progressed to brain death. Monitoring was initiated at a median [IQR] of 14.9 [10.9 - 20.6] hours from CA for a duration of 47.5 [27.1 - 75.1] hours. The time spent with impaired autoregulation was 22.6 [18.4 - 31.6] % of the recording duration, corresponding to 10.1 [6.9 - 15.9] hours. MAP OPT could be identified in 33 (94.3%) patients and 47.7 [32.1 - 59.6] % of the recording duration. The average MAP OPT was <75 mmHg in 2 (6.1%), 75 - 85 mmHg in 14 (42.4%), and >85 mmHg in 17 (51.5%) patients. MAP OPT did not differ between survivors and non-survivors (mean (SD) 87.2 (9.6) vs. 88.2 (12.1) mmHg respectively, p=0.86). Conclusion: MAP OPT could be identified in all but two patients and calculated for half of the recording duration. Average MAP OPT was ≥ 75 mmHg in 94% of our cohort. Future studies are needed to evaluate whether targeting personalized physiologic thresholds influences outcomes.