Background: Early stroke detection and intervention is critical to improve outcomes in at-risk patients. Optical brain pulse monitoring (OBPM) offers bilateral, non-invasive, continuous measurement of the brain pulse waveform, from which cerebral oxygen saturation (StO2%), intracranial pressure (ICP), and brain compliance can be derived, making it sensitive to reduced cerebral perfusion.
Objective: To observe OBPM changes during ischemic stroke and following reperfusion in a clinically relevant sheep model.
Methods: Eleven Merino wethers (18–24 months) underwent right middle cerebral artery occlusion (MCAO) for four hours, followed by reperfusion. OBPM measurements were taken in the ipsilateral hemisphere (n = 11) or bilaterally (n = 5) at baseline, during MCAO, early reperfusion (ER; ~30 minutes post-reperfusion), and late-reperfusion (LR; ~4 hours post-reperfusion). As a comparator, invasive brain tissue oxygen (PbtO2) monitoring was conducted in the ipsilateral hemisphere, and ICP monitoring in the contralateral hemisphere. Infarct volume post-reperfusion was measured using MRI. Generalized estimator models adjusted for false discovery were used with significance set at p < 0.05.
Results: The OBPM StO2% measurement showed significant decreases in both hemispheres, with larger drops in the setting of larger infarct volumes (p < 0.05). A significant reduction in PbtO2 was observed during MCAO (p < 0.001), normalizing during reperfusion. ICP analyses revealed significant reductions during MCAO and ER (p <0.01).
Conclusion: OBPM is a safe and promising tool for real-time stroke detection, with the potential to enable expeditious clinical decision-making and improve patient outcomes.