Good and highly efficient dialysis depends, not only on the machine or the technician, but more so on the quality & purity of water supplied to the machine. A patient is exposed to an average of 120 liters of water in a dialysis session of four hours. Hence the water supplied to the patient should be of the purest quality.
In the traditional hemodialysis, a maximum of 4 liters of water is removed from the body along with accumulated toxins. This is performed by a process called diffusion. The traditional hemodialysis machines have a single revolving blood pump. The hemodialysis machine can clear toxic molecules only up to 600 – 2000 daltons in size. The human kidney can clear toxic molecules up to 120,000 daltons in size. Hemodialysis needs dialysis grade water.
With the latest technical advances, and the availability of ultrapure water, a process called hemodiafiltration is now possible. In Hemodiafiltration up to 48 liters of ultrapure water are sent into and simultaneously removed from the patient in a four hour session. This results in highly enhanced clearance of toxins. This process combines both convection and diffusion and thus is vastly superior in toxin removal. Hemodiafiltration can clear up to 60,000 daltons, thus closely replicating normal kidney function.
The graph below illustrates the superiority of hemodiafiltration over hemodialysis and its close replication of human kidney’s clearance of molecules of increasing sizes.