spite of the lack of actual injury. I commonly chat or play music to distract myself. A matured fistula used for hemodialysis is normally about 6mm, so a bit larger than a major vein (the 'great saphenous vein' returning blood to your heart from each leg is 2-4mm) and a bit smaller than a major artery (the 'femoral artery' in a 50-year-old is about 10mm). Returning to the needle, that means a 14-15 gauge needle is taking up about a third of the 'tube'. Presumably the other two-thirds are to make sure your arm does not fall off due to gangrene. In my case, I have a bit-better-than-normal sized fistula (8mm) and given gangrene is not an issue, I can use quite a bit bigger of a needle. But this would be a bit too conspicuous since needles are physical objects and would need to be in inventory ("do you have any 8mm / 2-gauge needles available?") and someone needs to put them into my arm. Not a good way to keep a vampire under cover. Instead, I use normal needles and the machine lies about its flow rate. The 15-gauge needles in my arm are used by the dialysis machine to pump huge amounts of blood through my body at a much higher pressure (flow rate) than normal. This is equivalent to having larger needles and enables me to support dialysis for a dozen people during the four hour session.
❦ Removing dialysis needles — from your arm is less painful but more problematic. The problems arise from having two 2mm holes in your body, that have been there for as much as four hours. Your body does have a desire/ability to close these holes. But at the same time, your blood stream has a desire to take advantage of them: they are like two holes in a dike and are the "easy way out" for the blood. For a fistula, the dialysis needles are taken out in "reverse" order: the downstream needle (closer to returning to your heart) is taken out first and covered with _a lot_ of gauze and then pressurebandaged to your arm (or leg) to plug the hole. This combined with either hand-pressure or a mechanical (plastic) pressure system will - 35 -
