Can't be bothered waiting till 2000 here to contribute an insight. (I'm
inside warm and safe, but I confess I'm getting bored looking at pictures
of fireworks and young singers.) I'd rather talk about lactating breasts!

Lisa wrote:

<< Does anyone out there think that the standard hard plastic pump
accesory
kit
 flanges we use fall short on completely emptying all areas of the
breast. >

Jane answered:

< I am led to believe that it
is not just a massage action but the size of the tunnel of the pump
flange
that has a dramatic effect on pumping comfort and the effectiveness of
milk
removal.>

With my recent experience with one mother showing better milk removal on
one side with the largest flange, I second the motion. Here is my
reasoning.

The nipple is but a conduit for passage of the milk. Suction pulls on
flesh, not milk, until it exits the nipple. We are probably fortunate
that so many mothers have a well conditioned MER which adds its hydraulic
pressure from the back of the breast to the vacuum at the front of the
breast for fairly efficient milk removal. (All this has application to
direct feeding by the babies, too, come to think of it.)

Think for a moment of a toothpaste tube (or a tube of frosting for
decorating a cake, since it has a longer tip) as a familiar (if inexact)
model to help us imagine forces on a single milk sinus. The opening of
the tube is representing the point where milk exits a sinus and moves
through the nipple to exit through a nipple pore.

If we compress just behind the "neck" of the full tube, we of course get
some out, and if we compress a little further back, we get more.
But while we are so doing, the compression is also actually forcing the
remaining paste in a reverse direction, back toward the end seam of the
tube.

When we really want to empty the tube, we arrange that the compression
starts from the seam end, and we make sure to maintain that compression
so that no paste will escape our compression. That way, it cannot be
forced backward into the tail end of the tube.

(If you don't see this readily, try it on a real one. That's what I did
recently to test whether this might make a good, inexpensive
visual-tactile aid for a small audience of LC's) Now, try transferring
those insights to multiple milk sinuses in the breast.

The milk sinuses in each woman's separate breasts are at various depths
and locations behind and beneath the nipple, and do not necessarily have
any particular relationship with the visual size of the nipple.

Perhaps judging the size of flange needed might be estimated better by
digital compression of the areola to identify the location of the most
accessible milk sinuses. This is different from the common practice of
looking at the diameter of the nipple to estimate the appropriate flange.



In pumping, it seems to me that the breast, if soft and elastic enough,
is drawn into the flange and will compress itself against the bend and
the tunnel in the flange during the vacuum phase. If many of the milk
sinuses fall even 1/4 or 1/2" further back than the bend in the flange at
the height of the vacuum cycle, it seems as if they would actually be
subjected to a reverse upward compression that would be resisting the
force of the MER and massage.

If a larger flange is used, it seems that even though the compression
against the flange might fall behind the upper end of the milk sinus, it
would at least not be resisting the force of the MER. It might even be
crowding the sinuses enough inside the tunnel to close off the upper end,
so that the milk might be more likely to be forced in an outward
direction. Does anyone else see any logic in this?

Oh, and BTW, Happy New Year all!

K. Jean Cotterman RNC, IBCLC
Dayton, Ohio USA

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