>
>
> What I want to question about flow rates in bottles is the method of
> testing.  Babies do not use ONLY vacuum, they also use a little
> compression, isn't that so?  And from Hartmann's lab research, they use
> a variety of vacuums throughout a feeding.  When you are testing bottles
> for flow rate, you are using a pump and a flange.  This is not the same
> as a baby.  I found that out when I did my own tests on all the bottles
> I could find.  The flow rate TOTALLY depended on the vacuum applied AS
> WELL AS the type of nipple and it's hole size.  If you check out
> multiple flow rate bottles, the thing that controls the flow is the size
> or number of holes.  In the specialneeds feeder, it is the compression
> the baby exerts on the nipple that opens the hole up to the preset size
> that the nipple is set to.  If the baby is NOT compressing, the flow
> rate is driven by the vacuum strength.  I agree with Susan on the
> bornfree bottles - terrible - have had several babies coming in that
> won't open for mom, just chew on the tip.
>


You are correct in that there is NO feeding-bottle-nipple and no testing
device that results in a "real" simulation of breastfeeding suckling. Nada,
nothing, nyet! Be that as it may, vacuum/suction is primarily the way an
infant extracts milk from the breast. Recent Ramsay's recent ultrasound
research demonstrates that very little (if any) milk comes out during
breastfeeding suckling, except during the negative pressure (vacuum/suction)
phase. This research means it is much more likely that the wavelike motion
of the tongue from anterior to posterior palate is more to set up the tongue
drop that creates vacuum than it is to compress milk out of the breast.

One of the problems with infant bottle-feeding is that a baby CAN extract
milk via compression and, therefore, not have to actually suck, which
partially explains why premies and term newborns who have difficulty
breastfeeding can still get fluid out of a feeding-bottle-nipple. (Special
Feeders were designed for an infant with a specific feeding difficulty --
not the "regular" ineffective feeder.) When a feeding-bottle-nipple/teat is
slow enough, studies from the 50s (using x-ray!) show infants using a
sucking motion more similar to breastfeeding with its wave-like motion of
the tongue from anterior to posterior palate and then the drop to create
vacuum.

Fast flow -- whether with feeding-bottle-nipple or breast (with overactive
MER) -- "overwhelms" and threatens the airway and an infant understandably
cues distress, e.g. choking, gagging, coughing, sputtering, etc. But she/he
may also display distress in more subtle ways, especially after figuring out
some "mal"adaptive behaviors, e.g. clenching/biting/clamping down on the
bottle nipple, drooling excessively (by lowering oral tone to get rid of
some of the bolus), etc. Nasal flaring is also a sign of airway distress.

Size and shape of hole in the feeding-bottle-nipple "guide" flow -- more
vacumm will increase flow, but the ones that are faster flow than others at
lower vacuum will almost always still be the faster flow ones (compared to
those same slower flow ones) at higher vacuum pressures.

There is little, if any, research re: response of infant and related sucking
to feeding-bottle-nipple size, shape, material. There's tons (and that's
only mild hyperbole) re: effect of flow rate. Given a choice between more
appropriate flow rates (and a colleague and I are among those who tested a
gazillion (mild hyperbole again) in-hospital disposable and commercial
feeding-bottle-nipples in a systematic way using a breast pump. (Definitely
demonstrated that the words "slow flow" on the packaging are incredibly
subjective!) It's truly not perfect because it can't simulate breastfeeding,
but it's a smidge better than anecdote or compression testing -- which we
used before using the pump.

So given a choice between flow rate and BPA-free (or whatever the current
concern is), I'll consider flow primo. And one can always store, thaw or
heat the EBM in a BPA-free container and pour into the bottle with a demo'd
slow flow feeding-bottle-nipple.

It's really late where I am, so I hope this makes some kind of sense!

Karen Gromada

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