How does hyperventilation result in reduced ICP in head injury?

Inducing hypocapnia via hyperventilation reduces the partial pressure of arterial carbon dioxide (PaCO2), which incites vasoconstriction in the cerebral resistance arterioles. This constriction decrease cerebral blood flow, which reduces cerebral blood volume and, ultimately, decreases the patient’s ICP.

How does hyperthermia affect ICP?

Hyperthermia may increase cerebral metabolism (38,39), i.e. increased metabolic demand. The coupling between metabolism and CBF will increase CBF as well as the cerebral blood volume (CBV), which could cause an elevation of ICP.

What is the use of hyperventilation to lower intracranial pressure?

Hyperventilation promotes hypocapnia, which causes vasoconstriction in the cerebral arterioles and thus reduces cerebral blood flow and, to a lesser extent, cerebral blood volume effectively, decreasing temporarily intracranial pressure.

Can hypotension cause ICP?

Low ICP. Spontaneous intracranial hypotension may occur as a result of an occult leak of CSF into another body cavity. More commonly, decreased ICP is the result of lumbar puncture or other medical procedures involving the brain or spinal cord.

How does hyperventilation affect cerebral blood flow and ICP?

Hyperventilation is one known method of rapidly lowering ICP. Cerebral blood flow is largely dependent on PaCO2. Hyperventilation causes decreased PaCO2 which subsequently leads to arterial vasoconstriction thus lowering cerebral blood flow (CBF), cerebral blood volume, and ICP.

How does hyperventilation therapy work for hypocapnia?

Inducing hypocapnia via hyperventilation reduces the partial pressure of arterial carbon dioxide (PaCO 2 ), which incites vasoconstriction in the cerebral resistance arterioles. This constriction decrease cerebral blood flow, which reduces cerebral blood volume and, ultimately, decreases the patient’s ICP.

When did doctors start to use hyperventilation therapy?

Physicians started to explore hyperventilation (HV) as a way to lower cerebral blood volume (CBV) during the 1920s ( 1 ). One of the earliest documented descriptions of this treatment dates back to 1959, when Lundberg reported the use of HV to reduce increased levels of intracranial pressure (ICP) ( 2 ).

What are the effects of hyperventilation of PaCO2?

On the other hand, hyperventilation can also have adverse effects. Hyperventilation to PaCO2 levels below 20mmHg has been shown to induce cerebral ischemia. Cerebral ischemia with extreme hyperventilation is likely mediated by severe vasoconstriction of cerebral vessels and alkalosis induced leftward shift of the oxyhemoglobin curve,