Cerebral blood flow estimation using NIRS in cardiac arrest patients: correlation with ROSC outcomes

Out-of-hospital cardiac arrest (OHCA) is a critical emergency. Although elevated mean arterial pressure (MAP) would be expected to enhance cerebral blood flow (CBF) during cardiopulmonary resuscitation (CPR), direct clinical data remain limited. This study examined how CBF responds to varying MAP levels during CPR in OHCA patients.

This retrospective observational study included adult patients (≥18 years) with OHCA who underwent CPR with both invasive arterial monitoring and near-infrared spectroscopy (NIRS) measurements to assess cerebral blood flow changes were included. Mean arterial pressure was categorized into 20 mmHg intervals (0-20, 20-40, 40-60, 60-80 mmHg). Pearson correlation and linear regression analysis compared patients achieving return of spontaneous circulation (ROSC) with those who did not.

Among the 74 patients analyzed, NIRS-estimated CBF showed minimal responsiveness to MAP changes below 60 mmHg in both groups. A significant positive correlation between MAP and CBF emerged in the 60-80 mmHg range specifically among patients achieving ROSC (p < 0.001), but not in non-ROSC patients. Linear regression revealed steeper CBF increases with higher MAP values in the ROSC group beyond 60 mmHg.

The relationship between MAP and CBF during CPR varies by pressure range, with a positive correlation emerging at mean arterial pressure ≥60 mmHg, specifically among patients with better short-term outcomes. Maintaining mean arterial pressure ≥60 mmHg may be beneficial to optimizing cerebral blood flow during resuscitation.