Which of the following can deliver 90% oxygen?: (A) Venturi mask, (B) Rebreathing O2 mask, (C) Nasal prongs, (D) Non-rebreathing mask with O2reservoir bag
Answer is B. Non rebreathing masks: Can deliver upto 80% of oxygen. Rebreathing mask: When tightly fit, they can provide 100%oxygen.(Refer: Morgan's Clinical Anaesthesiology, 4th edition, pg no: 38-40)