A patient recovering from head injury. Which activity demonstrates understanding measures to prevent elevation of intracranial pressure?

• A. Eating high-fiber foods rather than using enemas and laxatives
• B. Taking a hot bath daily
• C. Straining to have a bowel movement
• D. Breathing rapidly into a bag

Answer: (A)

Preventing rises in intracranial pressure is about avoiding anything that increases venous pressure or cerebral blood flow. Constipation can lead to straining during a bowel movement, which includes a Valsalva maneuver that markedly raises intrathoracic and venous pressure, reducing drainage from the brain and raising ICP. A high-fiber diet keeps stools soft and regular, minimizing the need to strain and helping maintain stable ICP.

Other choices would tend to raise ICP or worsen cerebral perfusion: a hot bath can cause vasodilation and increased cerebral blood flow, potentially elevating ICP; straining to have a bowel movement directly increases intrathoracic pressure; and breathing rapidly into a bag raises CO2 levels, causing cerebral vasodilation and increased ICP.