Re: Carseats and oxygen levels, a question!
If your little guy is born before 37 weeks he'll have a car seat test in which he is put in the car seat at the 45 degree angle and put on a pulse oximeter which measures his oxygen levels. If he has desaturations in which his oxygen levels fall below a certain level, he will fail. If not, he'll pass. If his health problems effect his breathing, he'll likely still have a car seat test. The car seat test will likely be a few days before discharge.
Good luck with your little guy.