Baby choking

Does anyone's babies choke while bottle feeding? Mine will choke from time to time & will gasp like he can't get air or forgets to breath (more so in middle of the night). when he does it I am frantically patting him on his back & lifting him up to help him take a breath. It's only a few seconds but 1 time it looked like his lips were almost turning blue. I asked his ped who referred us for a swallow study at the children's hospital. I am questioning whether i am overreacting or not bc the swallow.study includes an xray which is also scary & I don't want to do if not necessary. Do any other moms have experience with choking while feeding or swallow studies on their LOs? Thanks!