A patient with a head injury has an intracranial pressure (ICF) of 18 mm Hg and the blood pressure is 134/80 mm Hg. What is the cerebral perfusion pressure (CPP)?

CPP (Cerebral Perfusion Pressure) is calculated as: CPP = MAP − ICP, where MAP is mean arterial pressure. First, calculate MAP: MAP = (SBP + 2 × DBP) ÷ 3 = (134 + 2 × 80) ÷ 3 = (134 + 160) ÷ 3 = 294 ÷ 3 = 98 mmHg. Then, CPP = MAP – ICP = 98 – 18 = 80 mmHg.