Transient Changes in Cerebral Tissue Oxygen, Glucose, and Temperature by Microstrokes: A Computational Study

Objective

This study focuses on evaluating the disruptions in key physiological parameters during microstroke events to assess their severity.

Methods

A mathematical model was developed to simulate the changes in cerebral tissue pO₂, glucose concentration, and temperature due to blood flow interruptions. The model considers variations in baseline cerebral blood flow (CBF), capillary density, and blood oxygen/glucose levels, as well as ambient temperature changes.

Results

Simulations indicate that complete blood flow obstruction still allows for limited glucose availability, supporting nonoxidative metabolism and potentially exacerbating lactate buildup and acidosis. Partial obstructions decrease tissue pO₂, with minimal impact on glucose level, which can remain almost unchanged or even slightly increase. Reduced CBF, capillary density, or blood oxygen due to aging or disease enhances hypoxia risk at lower obstruction levels, with capillary density having a significant effect on stroke severity by influencing both pO₂ and glucose levels. Conditions could lead to co-occurrence of hypoxia/hypoglycemia or hypoxia/hyperglycemia, each worsening outcomes. Temperature effects were minimal in deep brain regions but varied near the skull by 0.2–0.8°C depending on ambient temperature.

Conclusions

The model provides insights into the conditions driving severe stroke outcomes based on estimated levels of hypoxia, hypoglycemia, hyperglycemia, and temperature changes.