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: Surgery
Blood loss during major surgery is best estimated by - 
Select and explain. 
A. Visual assessment, B. Suction bottles, C. Transesophageal USG Doppler, D. Cardiac output by thermodilution
B: Suction bottles
Answer: B: Suction bottles 
Explanation: Blood loss during operation is measured by -
Weighing the swabs after use and subtracting the dry weight + Volume of blood collected in suction or drainage
This is k/a Gravimetric method of estimation of blood loss