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

Area of Science:

• Cardiology
• Neurology
• Emergency Medicine

Background:

• Out-of-hospital cardiac arrest (OHCA) is a life-threatening emergency.
• Optimizing cerebral blood flow (CBF) during cardiopulmonary resuscitation (CPR) is crucial for neurological recovery.
• The precise relationship between mean arterial pressure (MAP) and CBF during CPR remains incompletely understood.

Purpose of the Study:

• To investigate the association between varying MAP levels and CBF during CPR in OHCA patients.
• To determine if a specific MAP threshold optimizes CBF during resuscitation efforts.
• To compare CBF responses to MAP in patients who achieved return of spontaneous circulation (ROSC) versus those who did not.

Main Methods:

• Retrospective observational study of adult OHCA patients undergoing CPR.
• Invasive arterial monitoring for MAP and near-infrared spectroscopy (NIRS) for estimated CBF.
• MAP was stratified into 20 mmHg intervals (0-20, 20-40, 40-60, 60-80 mmHg).
• Pearson correlation and linear regression analyses were employed.

Main Results:

• CBF showed limited responsiveness to MAP below 60 mmHg in both ROSC and non-ROSC groups.
• A significant positive correlation between MAP and CBF was observed in the 60-80 mmHg range exclusively in patients who achieved ROSC (p < 0.001).
• Linear regression indicated steeper increases in CBF with higher MAP values (≥60 mmHg) in the ROSC group.

Conclusions:

• The impact of MAP on CBF during CPR is pressure-dependent, with a notable positive correlation emerging at MAP ≥ 60 mmHg.
• This positive correlation was specific to patients achieving ROSC, suggesting a potential outcome-specific benefit.
• Maintaining MAP ≥ 60 mmHg during CPR may be a viable strategy to enhance cerebral perfusion in OHCA patients, particularly those with favorable short-term outcomes.