The fluid that enters the kidney is basically blood serum with all the big cells and molecules filtered out. By the time it exits the kidney, all the useful stuff has been reclaimed and put back into the bloodstream....including a ton of water. So the urine that is produced is pretty concentrated.

In feline kidney failure, the water reclamation system breaks down so the cats lose vast quantities of water through the urine....and the urine is very dilute as a result.

Eventually the cats reach a point where they physically cannot drink enough water to balance the amount they are losing through their urine. At this point, they would become dehydrated and die. Instead, we can counter that by regularly administering sterile fluids as a large-volume injection under the skin of the back...the system will absorb them. This is normally done with a big needle, but for kitties who are on long-term management, that gets pretty painful for them so the tube is implanted allowing us to give fluids painlessly.

It's wicked cool technology. We have a couple sitting around in a drawer at work, but so far haven't gotten a client comfortable enough with the idea to actually go for it.

Sheree, thanks so much for sharing pics of your girl. I'm so glad you are doing this for her! Here is a link with a really terrific breakdown of the current ideas in managing CRF: http://www.vin.com/VINDBPub/SearchPB...00/PR00437.htm
If you don't yet have her on enalapril or benazepril, that would be something really important to start. High blood pressure is a huge factor in ongoing kidney damage.