Called for a man with lung cancer and COPD. He was satting in the low 80's on his home 02 with slight wheezing. We put him on a nonrebreather when his sats didn't improve with a few more liters by cannula. While his SAT went up to 100%, his end tidal also went from 37 up to 52, and his respirations dropped slightly. The point of all this is for all the debate about the hypoxic drive and not giving COPDers too much 02, if you are at a nursing home or a doctor's office and they tell you not to give over 2 liters while you are putting a mask, you can just say, not to worry, you are monitoring the patient's ventilations with capnography. If the ETCO2 gets too high indicating hypoventilation, you can turn the 02 down. If the patient is normoventilating, you can leave it high if the extra 02 makes them more comfortable.
Here's the trend summary (HR, SP02, ETC02, RR):