This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Anaesthesia
[{'content': 'All are true about Thiopentone except: \nSelect and explain. \nA. NaHCO3 is a preservative, B. Contraindicated in Porphyria, C. Agent of choice in shock, D. Has cerebroprotective action', 'role': 'user'}, {'content': 'Answer: C \nExplanation: C i.e. Agent of choice in shock Thiopentone, a pale yellow powder, is ultrasho acting smooth inducing agent because of rapid redistributionQ. It is used in 2.5% conc. at 2.5 - 4.5 mg/kg mixed with 6% anhydrous Na2CO3 as perservativeQ Thiopentone is contraindicated in porphyria, status asthmaticus, severe shock, pericardial temponade and uncompensated myocardial diseaseQ', 'role': 'assistant'}]