This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Trauma, Subject name: Surgery
Normal cerebral blood flow is 
Select and explain. 
A. 45 ml/min for every 100gm of brain tissue, B. 55 ml/min for every 100gm of brain tissue, C. 65 ml/min for every 100gm of brain tissue, D. 75 ml/min for every 100gm of brain tissue
B: 55 ml/min for every 100gm of brain tissue
Answer: B: 55 ml/min for every 100gm of brain tissue 
Explanation: Normal cerebral bloodflow (CBF) is about 55 mL per minute for every 100 gramsof brain tissue. Ischaemia results when this rate drops below20 mL per minute, and even lower levels will result in infarctionunless promptly corrected.Flow depends on cerebral perfusion pressure (CPP), the difference between mean aerial pressure (MAP) and intracranial pressure (ICP).CPP (75-105 mmHg) = MAP (90-110 mmHg) - ICP(5-15 mmHg)Bailey and love 27e 328