Update - Worried about L

This is the first time I am actually worried about one of my girls.  Today they are 3weeks 3days old / 31weeks 2day gestation.

Ainsley is doing great.. she rarely has D-Sat's (oxygen goes too low) and hasn't had any Brady's (heartrate goes too low) in over a week. She is doing so good they are taker her off the IV fluids sometime after 8pm tonight.  The other day she weighted 2lb 14oz (up 11oz from birth weight)

Lorelei on the other hand has been having a problem with her abdomen being enlarged. X-ray shows that its just trapped air. They think its from being fed continuously through the feeding tube which can also push in air but it doesn't have a way out. They are still feeding her this way but not going up on the amount until her tummy is better. Now she has another issue. She use to have 1 D-Sat and/or Brady per shift (so 2 in 24hrs). Now she is having 3-5 per shift. She full on stops breathing (holding her breath?) and the nurses have to wake her up by either by making noise or picking her up making her sit up. And its only after that she starts breathing again. They went back up on some of the oxygen settings and its not helping. They told me this isn't uncommon but they don't know why she is doing it. I am worried.  She weights 3lb 5oz (up 14oz).