Which statement accurately describes ketamine's effect on intracranial pressure?

Which statement accurately describes ketamine's effect on intracranial pressure?

• A. Ketamine can increase intracranial pressure unless PaCO2 is maintained.
• B. Ketamine decreases intracranial pressure.
• C. Ketamine has no effect on intracranial pressure.
• D. Ketamine reduces cerebral blood flow independently of PaCO2.

Answer: (A)

Ketamine tends to raise cerebral blood flow and metabolic activity, which can increase intracranial pressure. However, cerebral blood flow is highly sensitive to PaCO2: high CO2 levels cause vasodilation and further raise ICP, while keeping PaCO2 in the normal range limits this vasodilation and helps keep ICP from rising. So ketamine can elevate ICP if ventilation isn’t controlled, but maintaining normocapnia (PaCO2) prevents that rise. This makes the statement true: ketamine can increase ICP unless PaCO2 is kept in the normal range.

Ketamine tends to raise cerebral blood flow and metabolic activity, which can increase intracranial pressure. However, cerebral blood flow is highly sensitive to PaCO2: high CO2 levels cause vasodilation and further raise ICP, while keeping PaCO2 in the normal range limits this vasodilation and helps keep ICP from rising. So ketamine can elevate ICP if ventilation isn’t controlled, but maintaining normocapnia (PaCO2) prevents that rise. This makes the statement true: ketamine can increase ICP unless PaCO2 is kept in the normal range.