Earlier Detection of Brain Injury Using Optical Brain Pulse Monitoring in Critically Ill Patients Following Cardiac Arrest

IMPORTANCE

Point-of-care, non-invasive brain monitoring in critically ill patients following cardiac arrest could provide earlier detection of neurological injury and, when combined with earlier treatments, limit brain injury. Point-of-care monitoring could also enable better neuro-prognostication.

OBJECTIVES

The study assessed the time to detection of brain injury using optical brain pulse monitoring (OBPM) compared to routine brain monitoring. The association of OBPM signals with more severe forms of brain injury was also assessed.

DESIGN

Retrospective analysis of patients enrolled in an observational study.

SETTING

Critical care unit of a tertiary academic hospital.

PARTICIPANTS

Adult patients requiring mechanical ventilation in a critical care unit following a cardiac arrest.

MAIN OUTCOMES AND MEASURES

OBPM uses red and infrared light to capture brain pulse waveforms whose morphology reflects the relative arteriole and venous pressure levels driving microvascular blood flow in the brain. The OBPM sensors were placed bilaterally on the anterior temporal region of the scalp, over the middle cerebral artery territories. Time to brain injury detection was defined as the period from cardiac arrest to the first detection of brain injury by OBPM or routine monitoring.

RESULTS

Twelve patients were enrolled, three required veno-arterial extra-corporeal membrane oxygenator support. In-hospital mortality was 83% and eight patients developed global hypoxic-ischemic brain injury. The median time to detection of brain injury was 57 hours earlier using OBPM compared to routine monitoring (P < 0.01). In brain injured patients OBPM brain pulse morphologies changed over time and were often different between hemispheres, high amplitude respiratory waves were also present. Known poor prognostic brain pulse waveform morphologies were present in some patients with severe brain injury.

CONCLUSIONS AND RELEVANCE

OBPM detected brain injury earlier compared to routine brain monitoring. Earlier detection of neurological injury could improve patient outcomes through earlier treatment and better neuro-prognostication.

KEY POINTS