Abstract Body (Do not enter title and authors here): Introduction
Hemodynamic-directed cardiopulmonary resuscitation (HD-CPR) targets blood pressure (BP) goals during resuscitation and has shown improved outcomes compared to conventional algorithmic CPR. However, the relationship between specific BP targets and cerebral health remains poorly understood. Objective: Evaluate the association of intra- and post-arrest cerebral hemodynamics, assessed using non-invasive optical neuromonitoring, with CPR strategies that include higher and lower target HD-CPR and algorithmic CPR.
Hypothesis
Higher target HD-CPR will result in increased crerebral oxygenation (StO₂) and relative blood flow (rCBF) and blood volume (rCBV) compared to lower target HD-CPR or algorithmic CPR.
Methods
Invasive BP monitoring and non-invasive optical neuromonitoring were performed in a pediatric swine model of asphyxia-associated cardiac arrest. After baseline (5 min) and asphyxia (7 min), ventricular fibrillation was induced. Animals were randomized to 1) high target HD-CPR with a goal systolic BP of 110 and diastolic BP of 45 mmHg (n=15), 2) low target HD-CPR with a goal systolic BP of 80 and diastolic BP of 30 mmHg (n=15), or 3) algorithmic depth-directed CPR (n=15). During HD-CPR, vasopressor administration was titrated to BP goals versus protocolized administration every 4 min in algorithmic CPR. After 15 min of CPR, animals were eligible for defibrillation. Animals achieving return of spontaneous circulation (ROSC) were monitored for 4 hours post-ROSC. A Kruskal Wallis test compared cerebral hemodynamics between groups during baseline, asphyxia (7th min), CPR (15th min), and post-ROSC (10, 60, and 240th min). Since not all subjects achieved HD-CPR goals intra-arrest, a secondary analysis compared subjects where mean BP in the 10-15th min of CPR was at goal.
Results
No intra- or post-arrest group differences were observed in StO₂, rCBV, rCBF, and MAP (p>0.05; Fig. 1). In the secondary analysis of HD-CPR animals that achieved goal BP, StO₂ was higher in the high (n=8) vs. low (n=10) target BP groups (median [IQR]: 36.5 [32.9, 38.9] vs. 27.8 [20.1, 35.2], p=0.03).
Discussion
In our primary intention-to-treat analysis, no differences were observed between CPR strategies. However, high BP target HD-CPR that achieved BP goals increased cerebral oxygenation. This reinforces the established association between BP and cerebral oxygenation. Future work is needed to optimize HD-CPR strategies to consistently achieve higher blood pressures.