Does dialysis cause dehydration?

It can. Dialysis serves two functions. One is to remove some of the toxins in the blood that are no longer able to be removed by the kidneys due to kidney failure. The other is to remove fluid that has accumulated due to the diseased kidneys. If the dialysis prescription is incorrect in relation to the patient's "optimal" or dry weight, too much fluid can be removed and the person can become dehydrated.
Dialysis Problems. Because one of the goals in dialysis is to remove water, overly aggressive water removal can cause dehydration. This is a good source for further information: http://www.Kidneyabc.Com/dialysis/1574.Html.