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Starting hemodialysis is often a frightening experience. Hemodialysis machines are complicated and dialysis sessions often are punctuated by alarms. At the beginning of dialysis and at the end of dialysis a lot of things happen. Not knowing what it is can be anxiety provoking. The following step-by-step description of hemodialysis will hopefully clarify some things for people starting dialysis and allow others to gain a better understanding of what dialysis entails. ==Pre-dialysis== #Before or around the time the patient arrives for his/her scheduled session, a dialysis machine will be prepared. There are many models of dialysis machines, but typically in modern machines there will be a computer, CRT, a pump, and facility for disposable tubing and filters. The filters (the actual artificial kidneys) are cylindrical, clear plastic outside with the filter material visible inside (looks like thick paper). They are perhaps 15-18 inches long, and 2-3 inches thick. They have tubing connectors at both ends. The technician or nurse will set up plumbing on the machine in a moderately complex pattern that has been worked out to move blood through the filter, allow for saline drip (or not), allow for various other medications/chemicals to be administered. How the plumbing is set up may vary between models of machine and the types of filters. For some filters, it is necessary to clear sterilizing fluid from the filter before connecting the patient. This is done by altering the plumbing to push saline through the filter, and carefully checked with a type of litmus test. # The pump does not directly contact the blood or fluid in the plumbing — it works by applying pressure to the tubing, then moving that pressure point around. Think of a disk with a protrusion in it. Put this into a close fitting 270 degree enclosure. Put plastic tubing between the enclosure and the disk, entering and exiting in the 90 open degrees. Now imagine the disk turning. It will put pressure on the tubing, and the pressure point will roll around through the 270 degrees, forcing the fluid to move (see also Peristaltic pump). It is characteristic of dialysis machines that most of the blood out of the patients body at any given time is visible. This facilitates troubleshooting, particularly detection of clotting. #The patient arrives and is carefully weighed. Standing and sitting blood pressures are taken. Temperature is taken. #Access is set up. For patients with a fistula (a surgical modification to an arm or leg vein to make it more robust, and therefore usable for high capacity blood movement required by dialysis) this means inserting two large gauge needles into the fistula. This is painful for the patient but there are various methods of numbing the entry sites before the needles are inserted — the two most common are lignocaine (lidocaine), a local anaesthetic injected under the skin, and there is also a cream called EMLA which is applied to the skin 45 minutes before the needles are inserted. Fistulas are widely considered the desirable way to get access for hemodialysis, but they take time to set up and mature (anywhere between 5 weeks to 15 weeks). For other patients, access may be via a catheter installed to connect to large veins in the chest. Other arrangements can be made as well. #When access has been set up, the patient is then connected to the preconfigured plumbing, creating a complete loop through the pump and filter. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Step-by-step description of hemodialysis」の詳細全文を読む スポンサード リンク
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