Anne,

This sounds to me like a good place to use the Lact-Aid.  Besides the
fact that it would enable mom to feed fully at the breast and stimulate
her breasts while she is giving supplemental formula, it may stop the
problem with the baby throwing up the formula.  I guess there are
several reasons a baby may throw up formula but not breastmilk, but I
know one posibility is that babies tend to swallow more air when sucking
on a bottle than they do when nursing.  One of my adopted sons came to
me with pictures taken by the NICU nurses of the messes he had made from
spitting up formula from bottles.  However, when I nursed him with the
Lact-Aid, he almost never spat up and only a small amount when he did.
To start with, he was recieving only formula and no breastmilk, so I
know that is not what made the big difference.  He did, however, still
tend to spit up huge amounts when he was given an occasional bottle.

Hopefully, in your client's case, supplementation at the breast would be
very temporary.

Aloha,
Darillyn