Good dialysis depends on having a blood access (fistula, graft) that works well. Poorly functioning accesses cause inadequate dialysis as well as many visits to the hospital, most of which can be avoided if the problem is detected and corrected early. You should talk with your doctor about your access and ask him to check it and make sure it is working properly. If your arterial (red) needle “sucks” or your venous (blue) pressure is too high, there is a problem with your access and it needs to be fixed.