This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Respiratory System Pa 2, Subject name: Physiology
[{'content': 'Toxic effects of high oxygen tension include all of the following except: \nSelect and explain. \nA. Pulmonary edema, B. Decreased cerebral blood flow, C. Retinal damage, D. CNS excitation and convulsion', 'role': 'user'}, {'content': 'Answer: B \nExplanation: The O2 toxicity seems to be due to the production of superoxide anion, which is a free radical and H2O2. One of the principal effects is to oxidize the polyunsaturated fatty acids that are essential components of many membranous structures of the cells. Another effect is to oxidize some of the cellular enzymes. Increased alveolar pO2 may lead to absorption atelectasis, damage to pulmonary capillaries and pulmonary edema. Oxygen toxicity also includes retinopathy of prematurity (in infants), convulsions and coma.', 'role': 'assistant'}]