What is the expected mixed venous oxygen tension, in mm Hg, in a normal adult after breathing 100% oxygen for 10 minutes?

Ans. (c) 45Ref: American Board of Anesthesiology American Society of Anesthesiologists, Book A 1996 q-67Breathing 100% oxygen will not change the oxygen saturation much. In arterial blood it is around 97% saturation which corresponds to a PO2 of 100 mm HgIn venous blood it is 75% saturation which corresponds to a mixed venous oxygen tension of around 40-45 mm Hg