What's going on?

This morning Autumn has 2 of her MAJOR desats and had another one for the nurse this evening. Not sure what's going on. I fed her about 11:30am and was waiting to decompress her tummy and just sitting in the chair in her room when she started beeping. I looked and it said she was in the 80's (typical) and looked at her and she was crying and turning completely blue. Her arms were above her head and she was all rigid. She looked so scared....I quickly turned up the oxygen and started stimulating her and saying, "Autumn, Autumn, breathe baby girl". She started getting her color back and had gone down into the 40's. So, I was looking at her pulse ox when I heard her crying a little and looked at her again and she was down AGAIN...oxygen was still ALL the way up. I figured it must be a plug then and suctioned but she was completely clear. I started stimulating her again and she started turning pink again. I guess daddy her me this time telling her to breathe so he woke up and came to see what was going on. Gosh, it has been since March since she has turned COMPLETELY dusky and all rigid so it got my heart pumping since I'm not so use to those episodes anymore. So, not sure if it's her shunt or if she is doing it to herself when she gets upset or if it's just plainly her brainstem. I told my nurse to watch her extra carefully tonight and about an hour ago she decided to show him her little trick as well. He said she went to the 40's and was just staring and he started stimulating her and it scared her and she came back up...he said the vent was breathing for her while she was down. We've tested her for seizures but sometimes I wonder if when she looks blank like that if it is a seizure or if she just goes blank because her brain is not sending the signal to her? The sleep study in June may show us what's going on. Taking her bottle away and getting a new pulse ox seemed to fix the desat problems but with it coming back today it makes me wonder what is going on. Actually, now that I think about it...she had the desat with her nurse after being fed so I wonder if the acid reflux is getting worse and that is causing her the desats??? Lots of questions for the doctors at the next visit I guess.