Which of the following pathophysiologic conditions are considered as mediators of secondary brain injury in the presence of traumatic brain injury? I. elevated intracranial pressure II. hyperglycemia III. hypoglycemia IV. hypotension

A. I, II only
B. I, III only
C. II, III, IV only
D. I, II, III, IV only

ANS: D
A. Incorrect response: See explanation D.
B. Incorrect response: See explanation D.
C. Incorrect response: See explanation D.
D. Correct response: The following conditions are secondary mediators of brain injury in the presence of traumatic brain injury:
• ? Hypoxia
• ? Hypotension
• ? Hypercarbia or hypocarbia
• ? Hyperglycemia or hypoglycemia
• ? Elevated intracranial pressure
• ? Hyperpyrexia
Traumatic brain injury is characterized by primary irreversible injury from the initial insult, and the potential for secondary injury related to physiologic abnormalities and nosocomial complications often seen in critically ill patients.?