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': 'Which of the following is the most common method used to know depth of anaesthesia? \nSelect and explain. \nA. BIS, B. Oesophageal contractility, C. Depressed responses, D. Hypotension', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Ans:A. BISBispectral index:1st scientifically validated & commercially available monitor to check depth of anaesthesia.Utilizes many parameters (EEG signals, eye blinks) to calculate depth score.Adequate depth:Score of 45-60.Fully awake state:Score of 100Completely silent brain: 0.', 'role': 'assistant'}]