Vicky writes:

<you know, it's funny, just looking at pictures of this flange, it looks like it 
does reverse pressure softening with a tad of suction.>



So could about any small-tunneled pump flange, (except they don't contact the areola at a 180 degree surface angle) or baby, especially in a prone or laid-back position. That's actually where I got my first clue, by observing/palpating the areola of an overhydrated mom on about the fourth night. She had used the very same (probably a little 'laid back') position each time she nursed. The place where the baby's jaws had been compressing had much less edema than the "puffy areas", where the sides of the baby's mouth always made contact. I still remember a light bulb going off over my head that night on 11-7 way back in the 1960's!



You can cooperate even more fully with nature without the "tad of suction". Use a standard rubber nipple with the U.S. quarter size opening, as illustrated in Kyle Cotterman's diagrams, (without even cutting it off to observe for any potential color changes in the circulation, which was my first fear.)



Or use a standard nipple shield as is, as suggested in my JHL article.



Or cut off the silicone tab on the underside of the pacifier commonly passed out by some U.S. hospitals, and readily available in 2 packs (in multiple colors) in most U.S. drugstores. For most mothers, this opening will fit just fine around the circumference of the nipple at its base, allowing even a mom (or HCP or significant other) with long fingernails to exert simultaneous positive pressure all around the areola right at the base of the mom's nipple. 



Or for that matter, if desparate at 2.a.m., you could tell hubby to use the central opening of the plastic reel of the most well known brand of 'S - - - - -' cellophane tape. Remove the tape reel side. wash the loose half, and be careful to pad any sharp edges while doing RPS;-)



The easy availability of such items is the reason I have never responded to many of my friends' suggestions to "invent a gizmo" to sell, stock, leave the bedside or warm home to procure, etc. etc. for the few days it would be helpful. I would rather put my inventive efforts into creating further teaching materials for professionals and parents someday, when I learn how;-).



But the "tad of suction" you hypothesize actually nullifies the "reverse" part of RPS, probably raising the potential for the nipple itself to develop apparent enlargement due to local edema. (Martha Johnson of Eugene OR USA, and Rachel Myr of Norway first put me on to the fact that RPS can be gently used directly on a swollen nipple itself, to reduce the swelling back down to where the nipple button and base again look normal size . (Avoids having to issue larger flanges after a few days' pumping.)



The areola has a huge number of lymphatic capillaries, illustrated by dissections and drawings of a 17th century anatomist. It is named "Sappey's plexus" after him.  Google it for how he did it, in about the same era as photography was being invented elsewhere
        


The Guyton reference you will find in my article(s) explains the discovery that there is a natural vacuum, (a negative pressure of -0.6 mm. of mercury????, from memory) within distal lymphatic capillaries, which themselves, at the place where they originate, randomly in tissues, have no valves. They have an overlap in the cells that make up the capillary walls.  Nature moves lymph in such a fashion: excess interstitial fluid pressures push individual cells to "flap inward" to admit fluid into the lymphatic capillary till the pressures inside and outside are equal. 



At this point, these lining cell(s) flap back in place to their normal overlapped design again, till the upper lymphatic channels with valves "do their thing" in moving lymph along toward the venous circulation, and the whole pressure differential in the tissues starts all over again. (Again, always remember, vacuum does not pull. Other forces push.)



It is my understanding that the lymph always then moves forward destined to enter the venous system and the general circulation and never exits back out into interstitial tissues, except when tissue is frozen. (could that be the "freezer burn" we sometimes see in our frozen meats??) Anyway, be careful if and when you advise any covered icepacks, to state a limit of 20 minutes, no oftener than every 2 hours, as advised in physical therapy literature, to avoid any potential for frostbite damage to breast tissue. 



Anyway, my point has always been that external vacuum applied by pump (through the flanges) is overwhelmingly more powerful than the (minus) 0.6 mm. of mercury pressure ??? that nature provides to drain any excess interstitial fluid from the nipple-areolar tissues. Veterinary literature reports the effect of vacuum on dairy animal teats, and even vacuum applied to a non-engorged nipple-areolar complex (as Barbara Wilson-Clay has demonstrated in The Breastfeeding Atlas) allows interstitial fluid to move forward into the vacuum and simultanously overwhelms the natural mechanism within the lymphatic system just described.

My 3 for the day! Over and out!

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

 

             ***********************************************

Archives: http://community.lsoft.com/archives/LACTNET.html
To reach list owners: [log in to unmask]
Mail all list management commands to: [log in to unmask]
COMMANDS:
1. To temporarily stop your subscription write in the body of an email: set lactnet nomail
2. To start it again: set lactnet mail
3. To unsubscribe: unsubscribe lactnet
4. To get a comprehensive list of rules and directions: get lactnet welcome