In a message dated 97-02-25 09:49:45 EST, you write:

<< I have a new  premie mom using a Lactina.  She is not the first mentioning
 or asking about  the release of sucking of the pump making a burping sound,
 with some milk leakage but she is the first to describe that the milk
 burped so much that it sprayed her in the face!  I have seen it and heard
 it myself with other moms; sometimes it happens, sometimes it doesn't
 within a pumping session. >>


I would suggest the flange doesn't fit.  If her nipple does not fit down in
the "throat" and just "bounces" around in the flange resulting in leaks and
sprays, she needs a different size or shaped flange.  E-mail me privately if
you''d like some suggestions.
Liz Flight, RN, IBCLC