There are a couple possible issues here: 1) baby is having issues with the formula he is on and 2) he is having issues with a fast flow of milk. To let you know, I am a Lactation Consultant and specialize in feeding difficulties for babies who are on bottles (for whatever reason). :)
If it is a formula issue, then talk to his Ped about changing formulas to find one that works best with him. I do NOT EVER recommend Soy due to the phyto-estrogen issues and the overload of those hormones into babies bodies - it just isn't a good alternative. What we thought was safe 20 yrs ago we now know is not. There is a lot of info on the dangers of soy formula for infants. Easy to find...
If it is a pacing issue this will be seen by: baby guzzles his meal and is done drinking in 5-10 minutes; coughing, choking on the fast flow; he 'forgets' to breathe while drinking and has more that 4 swallows between breaths and when he does breathe it is very fast and then slows down - as if he is catching his breath.
If you observe and realize it is a pacing issue then YOU will need to help him learn to pace himself. Some babies just don't know how to do that - they are disorganized for whatever reason. They then need us to help them learn how to pace themselves safely. I wouldn't bother with the Adiri - it doesn't work - trust me on that one. The Dr. Brown standard (long slender nipple) can work fine ( I use this one all the time with babies who are having feeding difficulties and cannot breastfeed or need supplementation), but you have to control the flow. Here is how you do it:
Sit baby upright on your lap with his bottom between your legs (your legs together - this will form a nice little seat for him). Support his head at the nape of his neck (palm on his upper back and shoulders) letting it tip slightly back. Offer him the bottle. The bottle should be straight in his mouth - no tipping up or down or to the side. In other words Perpendicular. Adjust baby's body position (angle) (bringing him more upright or more laid back) to allow the nipple to be filled ONLY halfway with milk. This will slow down the flow for him. If he is taking more than 4 swallows before breathing, tip the bottle slightly down (towards your lap) just enough to drop the milk out of the nipple. He may/will continue to suck a few times and get air - don't worry! This can be burped up later. He will then stop sucking, pause and breathe. When he starts to suck again, tip the bottle up, back to perpendicular with the nipple filled only half-way with milk. Continue with this until he is done drinking. It should take him 15-20 minutes or so to drink a bottle of milk. As the bottle empties, go ahead and adjust the baby's body back to keep the nipple half-way filled with milk. Towards the end of the feeding he may be laying back quite a bit, but this will be ok because you will still be controlling the pace of the milk flow.
Ways to know baby is relaxed with the feed and feeling safe: His hands and arms will be relaxed and down by his sides rather than in tight little fists up by his face, and his face will be relaxed rather than worried brow, eyes wide open, look of possible fear...
A great bottle I found that works wonders with babies is actually the BreastFlow bottle by First Years. It helps in so many ways, slowing the feed down seems to be one. If I had to suggest a change for this little guy, that would be it. If you have other questions and/or would like to get more info please feel free to call me at ###-###-####. There is no charge for phone advice... :)
Good luck and thank you for taking such good care of this little guy. It is a work of love...
Warmly,
J. Simpson, IBCLC, CIIM