Workbench: You Can't Vacuum the Moon
www.concord.org/~btinker/workbench_web/unit1/1-15Suction.html‎

300+ years of research exist that vacuum does not pull; other forces push. Of interest in Wikipedia are the experiments
on Magdeburg hemishperes, and a lot more on Wikipedia.

All the breast pump engineers know this full well. It's understandable that lay people "think" from their senses that the vacuum is pulling. But as professionals we need to learn a lot more, and realize that when vacuum is applied, concentrated within the pump flange, the hydrostatic pressure of blood pressure is just one of the forces that pushes forward trying to neutralize the negative pressure of the vacuum. This is the reason that the nipple can begin to show redness and tenderness from pumping alone.


If there is any edema remaining from intrapartum IV's and oxytocin, fluid > 30% above the normal amount in the interstitial tissues, not bound by blood vessels or duct walls, then easily pushes itself forward, often to crowd the outside of the walls of the ducts in the subareolar tissue, slowing or completely blocking the exit of the milk. Increasing the vacuum can result in blisters full of interstitial fluid that has pushed itself forward under the skin.


If RPS is used (with the mother laying back 2/3 or more to use gravity to help, if her breast if larger than a C cup), edema is moved back 1 " or so behind the subareolar ducts, and an MER is usually stimulated within 90 seconds, (but maybe needing 10 minutes of constant gentle RPS in laid back position the first few times if edema is especially severe in the first 48-72 hours postpartum.) 


When milk does come out, it is the force of the MER that is one of the major forces pushing milk forward to the surface of the nipple to try to neutralize the negative pressure of the vacuum. Try having her start pumping sessions with gentle RPS for 1-2 minutes till the areola is soft and the MER happens before beginning to pump. When the milk slows down, pause, massage milk from the back of the breast forward, repeat RPS for 2 minutes, and resume pumping for 5-7 minutes or so till the next slowdown of the exit of the milk. She will get much more milk in just 15 -20 minutes of pumping without trauma to the skin or tissue of the nipple-areolar complex. 


I hope someone with an academic background would someday research this and write about it so we could supply every NICU in the land with a wall placque that says "VACUUM DOES NOT PULL: OTHER FORCES PUSH."


K. Jean Cotterman RNC-E, IBCLC
WIC Volunteer LC    Dayton OH

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