Hypocapnia indirectly reduces cerebral blood volume through reductions in arterial cerebral blood flow.
Despite its continued and frequent use, hypocapnia can actually aggravate cerebral hypoxia through reductions in oxygen supply and increases in cerebral oxygen demand.
In addition to inducing further cerebral injury, hypocapnia can cause deleterious effects on the heart, lung, and GI tract.
To date, there is no evidence that hypocapnia improves outcome in patients with traumatic brain injury or acute stroke.
Induced hypocapnia in critically ill ED patients with acute brain injury should primarily be reserved for those with imminent brain herniation.
References
Curley G, Kavanagh BP, Laffrey JG. Hypocapnia and the injured brain: More harm than benefit. Crit Care Med 2010; 38:1348-59.
