Low versus High Blood Pressure Targets After Out-Of-Hospital Cardiac Arrest

Introduction: The optimal level of blood pressure after out-of-hospital cardiac arrest (OHCA) is unknown. Hypotension may aggravate cerebral hypoperfusion exacerbating the post-anoxic brain injury. On the other hand, excessive vasopressor support may increase myocardial oxygen consumption and induce arrhythmias. We aimed to evaluate the effects of different blood pressure targets on the extent of brain injury and neurological outcome in patients resuscitated from OHCA. Methods: We performed a pooled post hoc analysis of OHCA patients randomised in the Neuroprotect (NCT02541591) and COMACARE (NCT02698917) trials to either mean arterial pressure (MAP) 65 mmHg or 80/85-100 mmHg targets for the first 36 h after ICU admission. We compared the serum neuron-specific enolase (NSE) concentrations between the groups at 24, 48 and 72 h after cardiac arrest and the neurological outcome according to the Cereberal Performance Category (CPC) scale at 6 months. We defined CPC 1-2 as good outcome and CPC 3-5 as poor outcome. In addition, we conducted a two-way analysis of variance to assess the effects of the MAP target and previous chronic hypertension on NSE concentrations. Results: All 224 patients included in the original studies were included in the analysis. Of these, 111 patients were randomised to the MAP 80/85-100 mmHg group and 113 patients to the MAP 65 mmHg group. Patients assigned to the higher MAP target had significantly higher blood pressure levels (p<0.001). We did not find any statistically significant difference in NSE concentrations (Figure 1) or good neurological outcome (50% in the lower MAP group vs. 56% in the higher MAP group, p=0.417) between the intervention groups. We did not observe statistically significant interaction between the MAP target and chronic hypertension for NSE (p=0.437). Conclusion: Targeting MAP 65 mmHg vs. MAP 80/85-100 mmHg after OHCA did not affect the extent of brain injury as determined by NSE concentration or neurological outcome at 6 months.