I had a severe asthma attack and had to go to the ER. When I was being checked in, I was coughing severely,SOB, and sweating but my O2 level was 98%. After about an hour the tech came in to give me my second breathing treatment and he saw that my O2 level had dropped to 86%. He started me on oxygen right away. I was a bit surprised because my symptoms had abated and I was feeling better. After a couple of hours of oxygen and my final breathing treatments, I was taken off oxygen and observed for about an hour. In that time my O2 fluctuated between 88-92%. This satisfied their requirement of 90% so I was able to go home. I was just wondering why it dropped so quickly, particularly when I was feeling better? And are there any symptoms because I didn't feel any?
Of course, it's impossible to know for sure after the fact what happened to you exactly, especially without being able to examine you. But if they checked your oxygen level using a pulse oximeter, then it's been my observation watching my mom over the past year or two (who has COPD) that oximetry is not always 100% accurate. At least not as accurate as arterial blood gases (a blood test requiring a lab draw) would be.
I've seen oximetry affected by hand temperature, position of the sensor on the fingertip and also by the technician. I suspect your initial reading was not quite as good as they measured it. 98% is darn good for someone who is coughing severely and gasping for breath.
Of course, your best bet would be to pose this question to your doctor, who can examine your hospital records and perhaps pick up on something else that was going on that would have affected it.
To your health,
Possibly a condition known as V/Q Mismatch which is not uncommon