Retaining CO2 at night...any chance this could be epilepsy med related?

Anna spent the night at CHOA (Children's Healthcare of Atlanta) in June.  Goodness what a month that was for us!  I almost felt like we should have rented a room that month as we were up there several times doing testing, the overnighter, doctor visits, etc.  Anyhoo, the neurologist wanted her to have a sleep study since I reported her sleepwalking, snoring, drooling at night, and overall restlessness.  The results a few weeks ago:  no sleep apnea BUT she is retaining CO2 at night.  So now he has referred her to a pediatric pulmonologist.  SIGH.  It's after the fact that I am now wondering if maybe this is medicine related...or could it be a seizure (drooling is very evident) or am I just nuts?  You all know how hard it can be to get referrals...the wait...and we deal with an HMO.  Has anyone else experienced this with their child?  Anna takes Trileptal (450mg AM - 600mg PM) and this last EEG (sleep deprived) showed "blips"...the tendency for seizure activity even on the meds (which is why he increased it to her current dosage).  I mean, I know I'll get answers from the ped pulmonologist, but I thought I'd ask around here too,  to get some feedback.