If ICP > 20 mmHg, which immediate intervention is recommended?

• A. Elevate HOB
• B. Hyperventilation
• C. Mannitol
• D. Administer antibiotics

Answer: (B)

When intracranial pressure is elevated above normal, the quickest way to lower it is to reduce cerebral blood volume. Controlled hyperventilation does this by lowering arterial CO2 (PaCO2). With lower PaCO2, cerebral arterioles constrict, decreasing blood flow to the brain and rapidly lowering ICP. This is a rapid, temporary measure used while definitive therapies are planned. Aim for a PaCO2 around 30–35 mmHg for a short period, then reassess. It’s important to avoid prolonged or overly aggressive hyperventilation because excessive vasoconstriction can compromise cerebral perfusion and cause ischemia. Elevating the head of the bed helps with drainage but doesn’t reduce ICP as quickly; mannitol or hypertonic saline can also lower ICP, but they’re not as immediate as hyperventilation, and antibiotics address infection rather than ICP control.