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
A mill-wheel type of murmur during laparoscopy suggests 
Select and explain. 
A. Tension pneumothorax, B. intra-abdominal bleeding, C. Gas embolism, D. pre-existing valvular disease
C: Gas embolism
Answer: C: Gas embolism 
Explanation: 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