---- LACTNET automatic digest system <[log in to unmask]> wrote: 
> There are 8 messages totalling 431 lines in this issue.
> 
> Topics in this special issue:
> 
> I am confused about something that maybe one of our suck experts can  
> clarify.  I thought that the "old" idea was that babies removed milk  
> by compressing the subareolar milk ducts, but that current  
> information shows that negative pressure (suction) rather than  
> compression is what removes the milk, in conjunction with the MER  
> basically pushing the milk out.
> 
> So if this is true, why would it be desirable to use a bottle that  
> requires compression?  Shouldn't a traditional bottle that uses only  
> suction be more similar to the breast, according to the current  
> model?  If a baby starts learning that compression removes milk, then  
> wouldn't that result in a lot of pinching the breast?
> 
> Warmly,
> Lynnette Hafken, MA, LLLL, IBCLC
> Germantown, MD, USA


I'm confused with Lynnette. From Donna Ramsay, PhD's presentation re: "Investigation of the Sucking Dynamics of the Breastfeeding Term Infant:Ultrasound and intraoral vacuum research" on 7/8/05 at the ILCA conference, I also got the impression that her ultrasound studies of sucking indicated that it was the negative pressure, especially in conjunction with MER, that seemed to "deliver" milk. I thought she found/saw on ultrasound that insignificant (if any) milk was expelled during the period we'd thought of as a compression during the tongue's wave-like movements of the breast up against the palate. (This was a difficult paradigm for me to shift.)

As for why then the wavelike movement against the palate -- a colleague who has a MA, CCC-SLP, IBCLC suggests it may simply be the way the baby sets up the next negative pressure event. Makes lots of sense to me... The compression used on a bottle teat is not necessarily the kind that is part of the negative pressure cycle; it often appears to be associated with clenching, which can be an "adaptive" (maladaptive when used long term) behavior to slow/control flow from a bottle teat or can be related to some underlying physiological issue resulting in feeding difficulty. Because when negative pressure is applied to a bottle teat, our teat trials using a self-cycling pump indicate that the flow through is determined by the hole in the teat -- the bolus is the bolus is the bolus. (This did not change when we changed the angle the bottle was held at.) If too much, and many teats deliver too much, what's a baby to do but move to compression and/or clenching or lower oral tone to drool out some of the bolus.

Our trial indicated the Comfi would be too fast a flow for most newborns -- possibly less compatible with oral behaviors needed for BF. Someone mentioned an apparent increase in flow. That is ALWAYS going to be an issue -- and why "old" research on teats is meaningless because most of the teats tested (per lit review data) have been sold to other companies, were before laser hole-drilling, etc. The method we developed for testing teats could be duplicated by most IBCLCs, so ongoing testing is tedious but possible! Ongoing testing plus asking for feedback re: infant response to teat, esp. subtle airway distress cues probably will point toward the "best of the worst" in terms of teats. If I recall correctly, at another ILCA conference presentation in the mid-90s Dr. Woolridge said the x-ray studies in the 50s indicated that babies used a similar kind of sucking on breast and bottle unless flow rate increased. If so, an appropriate teat should allow for similar oral behaviors whether at breast or bottle...unless an underlying issue is affecting feeding.

Never thought I'd be so engrossed in bottle teats...

K

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