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
Fixed performance device is – 
Select and explain. 
A. Ventury mask, B. Nasal cannula, C. Simple mask, D. Non rebreathing mask
A: Ventury mask
Answer: A: Ventury mask 
Explanation: Ventimask (venturi mask) is a fixed performance (high flow) oxygen delivery device.
Nasal cannula, non-rebreathing mask (Hudson mask) and simple mask are variable performance (low flow) devices.