This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Respiratory system, Subject name: Medicine
[{'content': 'A mill-wheel type of murmur during laparoscopy suggests \nSelect and explain. \nA. Tension pneumothorax, B. intra-abdominal bleeding, C. Gas embolism, D. pre-existing valvular disease', 'role': 'user'}, {'content': 'Answer: C \nExplanation: The \'water-wheel\' or \'mill-wheel\' murmur is classically associated with large intracardiac air emboli and described as a "characteristic splashing auscultatory sound due to the presence of gas in the cardiac chambers." . Most venous air (gas) emboli are iatrogenic . Ref Davidson edition23rd pg 620', 'role': 'assistant'}]