Experience with the JMS fully automated dialysis machine.

A fully automated dialysis machine has been developed and evaluated clinically. It uses highly pure dialysate (produced by a new dialysate cleaning system) instead of the conventional physiologic saline for the processes of priming, guiding blood to the dialysis machine, replenishing fluid, and returning the blood to the body. The piping for the dialysate is in the shape of a loop, and the dialyzer coupler has no mechanical parts that might become contaminated. As a result of these and certain other improvements in machine design, it is now possible to obtain reasonably clean dialysate. For the priming process, the machine uses a volume of up to 4 L of the dialysate after reverse filtration from the dialyzer. Most foreign matter or eluates can be removed from the dialyzer and the blood channels. Before blood is guided out of the body into the dialysis system, the needles inserted in the artery and vein are simultaneously connected to the blood channel, and the dialysate remaining in the channel is removed from the dialyzer. If the patient's blood pressure falls during dialysis, the dialysate can be replenished at any desired flow rate for reverse filtration. Blood return can be started automatically when the planned dialysis time has elapsed and the target water volume has been removed. The cleaned dialysate is infused from the dialyzer into the blood channel by reverse filtration to allow the blood to be returned to the body via both the artery and the vein at the same time. A total of 216 units of this fully automated dialysis machine have been placed in service at two of our facilities. During the 6 month period beginning in July 2001, they were used for 40,000 hemodialysis sessions in 516 patients. During the dialysate preparation process, the endotoxin levels in the reverse osmosis (RO) water, prefilter dialysate, and reverse filtered dialysate were all less than 1 EU/L. The time required to guide blood into the dialyzer (n = 39) decreased from the 4.6 +/- 1.4 minutes with the conventional machines to 3.2 +/- 0.6 minutes with the new machine (p < 0.01). The time required to return blood to the body also decreased from 8.6 +/- 2.2 minutes with the conventional machines to 6.8 +/- 0.7 minutes with the new machine (n = 34). No mechanical trouble was encountered with the fully automated dialysis machine units during the 40,000 hemodialysis sessions, and the workload of the dialysis unit staff in terms of the time needed to guide out and return blood to the body was significantly reduced. Because the machine simplifies the maneuvers required during hemodialysis, it is expected to contribute greatly to preventing medical accidents and in hospital infections associated with hemodialysis.