What Causes Drop In Oxygen Levels And Pulse Rate On Exertion?

9 My wife has very serious COPM we are trying ton get her qualified for a double lung transplant. Right now is her stats keep going up and down a little bit ago her 02 was 79 pulse 135. Any exertion causes this normal she runs 02 about 96 pulse 110. When it was up I wanted to take her back to the ER, she does not want to as she has had 11 admissions. But these stats worry me.