Report Muffled hearing on standing up after prolonged sitting. SpO2 drops momentarily when lying down in bed, and low SpO2 on plane.. (Previous DVT/PE) in Dysautonomia Discussion Posted February 28, 2020 I know this is an old thread. Thanks everyone for your insight. I still have issues, when I get up from bed to go to restroom. Then I lay back down, and SpO2 will drop to 89-90% for a minute. I have to either wait and it goes up or start taking some deeper breathes. Then it's normal again. I think I may need to see another dysautonomia doctor. I'm not sure what else it could be, but the symptom started after I had my last DVT/PE.