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: Radiology
[{'content': 'Most sensitive investigation for air embolism is – \nSelect and explain. \nA. Decreased tidal volume of CO2, B. Decreased tidal volume of NO2, C. Doppler ultrasound, D. Central venous presure', 'role': 'user'}, {'content': 'Answer: C \nExplanation: Although transesophageal echocardiography (TEE) is the most sensitive method for venous air embolism (VAE) detection and is considered the "gold standard", it is costly and more invasive. When properly placed, a precordial Doppler is capable of identifying VAE at an air infusion rate as low as 0.015 ml/kg/ min and consistently at a rate of 0.021 ml/kg/ min.', 'role': 'assistant'}]