Oh, I'm so sorry - how scary!! Since your baby vomited, it is possible that he aspirated some of the vomit into his airway. If the aspirate made it into his lungs, the vet will be able to hear the "wheeze" in his lungs. So, that would be one thing. If something else entirely triggered the whole episode, it would be difficult to say. I will be thinking of you and your baby today - and will be watching for an update.
[I had a breathing episode w/ Marcel just last Friday at 2am and ended up at the ER. I believe he inhaled a feather from the bed - I literally thought he was going to die, that's how much his airway was occluded - so I know exactly how you feel.
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