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': 'A 40 yr old male with controlled thyrotoxicosis and Carcinoma rectum was undergoing laparcopic abdominoperineal resection, during which he was found to have decreased Blood Pressure and Hea Rate. On examination, a mill-wheal murmur was heard. The end tidal pCO2 was observed found reducing from 40 to 10. What is the most likely diagnosis? \nSelect and explain. \nA. Air embolism, B. Thyroid storm, C. Blood loss, D. Acute hypoxia', 'role': 'user'}, {'content': 'Answer: A \nExplanation: A i.e. Air embolism', 'role': 'assistant'}]