6 weeks old baby chocking while sleeping

So when my baby had a cold a while back she had episode of chocking and not breathing due to her being so congested and when I went to her pediatric and Texas Children’s they said she was very healthy and it was just due to her being congested. Well the other night and last night it happen again she started choking on her salvia or mucus where she almost couldn’t breath again but it hasn’t happen again after I used Saline Spray in her nose and used the bulb thing. I know if I take her back to her pediatrician there just gonna tell me the same thing. Any ideas on how to make sure she doesn’t choke on her spit or whatever it is I really want to say it’s mucus.