Uneven Respirations...quick question

I had a pediatric patient with muscular dystrophy and a trach. They were very very thin and couldnt put on weight. There respirations were unlabored but they seemed to be slightly uneven. Their right side expanded slightly less than the left. Sats were good. No signs of respiratory distress. They were given a chest xray and were given an ok to go home (no pneumonia/infections). So I am curious as to why their respirations were like that. First thing I think of when I hear uneven respirations is collapsed lung but I am sure they would be in respiratory distress or would show up on xray. Any ideas??
Might have a paralyzed or markedly weaker diaphragm on one side.

muscular dystrophy affects the muscles, overtime the breathing muscles weaken and they will eventually need a ventilator to breathe. they have to be followed by a lung and heart specialist

Some irregularity in respiration's is normal. Although, In muscular dystrophy it is a prevalent issue and a common problem to be watched. It occurs in varying degrees according to what type of MD they have. Weakness and wasting of voluntary muscles in the face, neck and lower arms and legs are common in muscular dystrophy. Muscles between the ribs and those of the diaphragm, which moves up and down to allow inhalation and exhalation of air, also can be weakened Infants with congenital MMD have severe muscle weakness, including weakening of the muscles that control breathing and swallowing. These problems can be life-threatening and need intensive care.Especially when caring for children it is important to educate yourself completely on their diagnosis and the nuances to their particular disease process...It can be a matter of under reacting or over reacting, either of which can cause them their life. GOd bless....http://www.mda.org/publications/fa-mmd-qa.htmlhttp://erj.ersjournals.com/content/8/5/815.full.pdf