You have a lot of questions - good for you! Let me start by saying like anything else, you can only learn so much before hand, it won't make sense until you live with it. This link has a ton of info. Many categories (equipment, surgery etc).
<a target=_blank class=ftalternatingbarlinklarge href="http://www3.nbnet.nb.ca/normap/gtube.htm
">http://www3.nbnet.nb.ca/normap/gtube.htm
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Basically once you have the tube in place you begin night feeds. The formula is put into a bag with a long tube. The tube goes through a pump (Kangaroo pump) and connects to a connector tube. One end hooks into your son's button. The pump is set to run over several hours. Most of the time it is set for overnight or 8 hours. The rate can be adjusted for faster or slower. It will take a few tries to get the right setting so your son won't feel too full when he wakes up.
Formula varies too (consistancy, calories, vitamins- etc). It took us a few tries to find the right fit for that too.
Did your doc talk to you about the kid of button Parker will be getting? There is the MIC-KEY style which is pretty common. There is also the Bard style. There are pros and cons to both. Check the links. My kids chose the Bard because it is flatter against their stomach. BUT it can come undone easier than a MIC-KEY.
My funny story (not so funny at the time) is during the first few months of having the tubes they came disconnected at night and leaked all over the bedding. We've since used rubber bed pads and taped down the tubes. Once, Jesse's tube came undone and dropped on the floor where it continued to pump ALL NIGHT. It seeped into the carpet, through the floor boards and into the cellar! I found a hug puddle on the cellar floor- sticky and gross the next morning. YUCK!
As far as cleaning, its not too bad. The tubes rinse out and can be re-used for a week. The bags get thrown away every morning. Storage for all the stuff is another story. We ended up getting new beds for the boys with storage drawers underneath. The tubes, bags, tape, gauze all take up a lot of room, never mind the cases of formula!
I'll stop talking now. But please ask anything!