Why is hyperventilation used in a patient with a subdural hematoma?

In the context of a patient with a subdural hematoma, hyperventilation is employed primarily to induce cerebral vasoconstriction. This physiological response leads to a decrease in cerebral blood flow, which can help manage increased intracranial pressure. By reducing blood flow to the brain, hyperventilation can potentially limit the expansion of the hematoma and alleviate symptoms associated with elevated intracranial pressure.

In cases of elevated intracranial pressure, like that which can occur with a subdural hematoma, controlling the cerebral blood volume is essential in preventing further neurological damage. Hyperventilation decreases the concentration of carbon dioxide (CO2) in the blood, resulting in respiratory alkalosis. This drop in CO2 prompts the blood vessels in the brain to constrict, thereby reducing the overall volume of blood within the cranial cavity.

This therapeutic strategy is particularly important in acute settings where rapid intervention is needed in the face of life-threatening increased intracranial pressure. Other potential choices might focus on aspects like oxygenation or pulmonary health, but their relevance is not as directly connected to the urgent needs presented by a subdural hematoma as vasoconstriction is.