This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Head and neck, Subject name: Surgery
The cause of systemic secondary insult to injured brain include all of the following except: 
Select and explain. 
A. Hypercapnia, B. Hypoxemia, C. Hypotension, D. Hypothermia
D: Hypothermia
Answer: D: Hypothermia 
Explanation: Causes of secondary Brain injury Hypoxia: pO2 < 8kPa Hypotension: SBP < 90 mmHg Raised ICP: ICP>20mmHg Low cerebral perfusion pressure: CPP<65mmHg Hypercapnia Pyrexia(Hypehermia) Seizures Metabolic disturbances (Hyperglycemia) Ref: Bailey 25th edition Pgno: 299