TBI Physiology of the Brain 2

Question 1

What is the normal intracranial pressure (ICP) range for a resting adult?

Accepted Answer

5–15 mmHg

Answer

Normal adult ICP is roughly 5–15 mmHg, and sustained values above 20–22 mmHg are treated.

Question 2

How is cerebral perfusion pressure (CPP) calculated?

Accepted Answer

MAP − ICP

Answer

CPP equals mean arterial pressure minus intracranial pressure.

Question 3

Which combination makes up Cushing's triad, a sign of severely raised ICP?

Accepted Answer

Hypertension, bradycardia, irregular respirations

Answer

Cushing's triad is hypertension, bradycardia and irregular respirations from brainstem compression.

Question 4

Cerebral autoregulation normally keeps cerebral blood flow constant across approximately which MAP range?

Accepted Answer

50–150 mmHg

Answer

Autoregulation maintains steady flow at MAP of about 50–150 mmHg, and this is often impaired after TBI.

Question 5

How does an elevated PaCO2 (hypercapnia) affect the cerebral vessels?

Accepted Answer

Vasodilation increasing cerebral blood volume and ICP

Answer

CO2 is a potent vasodilator, so hypercapnia increases cerebral blood volume and ICP.

TBI - Traumatic Brain Injury Certification Practice Test