Brain temperature: physiology and pathophysiology after brain injury

Abstract

The regulation of brain temperature is largely dependent on the metabolic activity of brain tissue and remains complex. In intensive care clinical practice, the continuous monitoring of core temperature in patients with brain injury is currently highly recommended. After major brain injury, brain temperature is often higher than and can vary independently of systemic temperature. It has been shown that in cases of brain injury, the brain is extremely sensitive and vulnerable to small variations in temperature. The prevention of fever has been proposed as a therapeutic tool to limit neuronal injury. However, temperature control after traumatic brain injury, subarachnoid hemorrhage, or stroke can be challenging. Furthermore, fever may also have beneficial effects, especially in cases involving infections. While therapeutic hypothermia has shown beneficial effects in animal models, its use is still debated in clinical practice. This paper aims to describe the physiology and pathophysiology of changes in brain temperature after brain injury and to study the effects of controlling brain temperature after such injury.

Figure 1

Heat production during energy metabolism. This schema is valid whatever the cell type.

Figure 2

Relationship between oxygen partial pressure (PO₂) and oxygen saturation of hemoglobin (SO₂). Hypothermia increases the affinity of hemoglobin for oxygen, according to Tremey and Vigué [51].