This is kind of straying from the original question, but working in a hospital, im always amazed at this near obsession with weaning patients off o2, even when their o2 sat is somewhat low. Obviously the considerations are different when you are talking about a long term solution to the patients situation.
I guess I dont know enough yet to understand the reasons for this, but its definitely a different mindset from EMS, where more o2 is the solution for everything. I work as a PCT and Ive ambulated a patient who is now gasping and their 02 is dropping down to 88 and the EMT in me thinks hey just turn up their o2 a little, but if I did that without getting permission from an RN or RT id be toast.