Elevated intracranial pressure (ICP) in TBI

1. What is a normal ICP? How is elevated ICP defined?
2. What is the relationship between ICP and cerebral perfusion pressure (CPP) and MAP?
3. What are indications for continuous monitoring of ICP?
4. What factors may increase ICP?
5. What are three methods used to monitor ICP?
6. What are common methods used to decrease ICP?

Answers:
1. Normal is 2-5mmHg. Elevated ICP is defined as >20mmHg for more than 5min. At >40mmHg, there is neurologic dysfunction and impairment. >60mmHg is fatal.
2. Increased ICP reduces CPP.
CPP = MAP - ICP.
3. Patient in coma (GCS <8) with CT findings of increased ICP; deep coma (GCS <6) without hematoma; severe chest and facial injuries with moderate/severe head injury (GCS<12); after evacuation of IC hemorrhage if pt in coma beforehand.
4. Fever, hyperglycemia, hyponatremia, seizures, turning head (especially to left side), loud noise, vigorous PT, chest PT, suctioning, hypertension.
5. Papilledema (develops in 12-24 hrs), CT scan, LP.
6. Elevate head of bed 30 degrees, hyperventilation (use with caution since this decreases brain PO2), osmotic agents (mannitol), furosemide, avoid HTN, barbiturates, surgical decompression. Hypothermia and steroids have not proven to be beneficial.