What can hyperventilation do to casualties with a traumatic brain injury (TBI)?

In cases of traumatic brain injury (TBI), hyperventilation can lead to a decrease in carbon dioxide (CO2) levels in the blood, a phenomenon known as hypocapnia. This reduction in CO2 causes cerebral vasoconstriction, which can reduce blood flow to the brain. While reduced intracranial pressure might seem beneficial, the accompanying decrease in cerebral blood flow can lead to ischemia, meaning that the brain may not receive adequate blood supply and oxygen, ultimately worsening the patient’s condition and increasing the risk of secondary brain injury.

Managing the balance of carbon dioxide levels is critical in TBI cases; aggressive hyperventilation can inadvertently harm the patient by promoting vasoconstriction and ultimately diminishing the oxygen delivery necessary for recovery.