Nutritive suck is characterized by a low suck:swallow ratio.  Usually 1:1 or
2:1.  It is slower than NNS which allows for a breath to be taken between
swallows.  Anytime breathing has to be intersperced during sucks and
swallows respiratory rate (RR) will be decreased.  This is why feeding is
often aerobic exercise for babies, and can need for the chance to stop the
swallowing part of feeding to do some catch-up breathing.  NNS is
characterised by a faster rate of sucking and a lower rate of swallowing.  I
think there is probably always going to be some small amts of intake with
NNS in breastfed babies, but the swallow rate is about 5-6 sucks:1 swallow.
Sometimes tho, when I have done test weights, what baby is swallowing seems
to be own secretions, as there is no discernable intake. There is a lot of
discussion (with studies cited) in the OT/PT literature about observable
differences in nutritive vs NNS.

I saw a 36 week old baby yest. born 6.2lb down (at 3 wk pp) to 4.15.  Baby
feeds every hour.  I observed baby at breast and discerned no evidence of
nutritive suck, as was verified by test weight. He is happy to do a shallow,
rapid, NNS for hours at the breast. I tried to finger feed, and baby refused
my finger.  He weakly licked a few drops on my finger-tip.  I cup fed and
observed that while he would willingly extend his tongue and lap a few
drops, he had extreme difficulty organizing the milk into a bolus he could
swallow.  I observed it pooling under his tongue and sitting there for
several seconds before he attempted a swallow.  During the swallow, his brow
furrowed, his arms got stiff, and his fingers splayed.  He had to swallow
several times to get the milk (pumped mother's milk) down.  To get 3 such
swallows of a few drops each took 5 minutes.  I offered him a Haberman
feeder.  He willingly sucked on the teat (just as willingly as he took mom's
breast) and again had extreme difficulty swallowing.  He formed a weak seal
around the teat, and milk spilled out the corner of his mouth.  He evidenced
the same kinds of motoric stress signals during swallowing.

It is hard to say at this point whether the baby's inability to feed
normally at this point is due to the excessive weight loss or some
underlying problem. The challenge is going to be to find any way to get this
baby to feed, and I am not sure he is manifesting the capability for oral
feeds at this time.  This is what I am communicating to the physician, and
am recommending a swallowing study.

I think nipple confusion is a real phenomenon, however, I don't think that's
what we are talking about when we see babies with feeding problems.  There
we have babies who can't nurse normally because they can't make the
oral-motor moves necessary to make it work. Our challenge there is preserve
all breastfeeding options while we stabilize the baby any way we can.
Again, I refer people to Lawrence, Seacat and Nieferts very insightful
article about the need for a formal definition about what nipple confusion
is and isn't.

Barbara

Barbara Wilson-Clay, BS, IBCLC
Private Practice, Austin, Texas
Owner, Lactnews On-Line Conference Page
http://moontower.com/bwc/lactnews.html