title: Assessing the adequacy of dialysis.
abstract: In previous work, probes of brain function (quantified EEG and cognitive performance) objectively measured clinical differences patients with chronic renal failure before and after treatment with maintenance haemodialysis or transplantation. This study applied those measures (EEG-discriminant score; choice reaction time, CRT; continuous memory test, CMT; clinical-symptom/self-evaluation questionnaire, CSE) in a prospective experiment to determine whether our standard amount (time) of thrice weekly dialysis could be reduced without inducing some degree of clinical uraemia. In 10 patients a 6 month experimental (E) period was preceded by a 3 month control (CI) and followed by a 3--6 month control (C2) period. During E dialysis time was reduced so that residual renal (Kr) plus dialyser (Kd) urea clearance per week per litre of patients' body water approximated 50--80 percent of the control-level of 3000ml/wk/L. In response average values of all measures worsened; EEG, 54 percent; CRT, 2.5 percent; CMT, 21 percent; and CSE, 11 percent. BUN levels rose slightly, urea generation rates fell, and patients insisted that they felt better as they recorded more severe symptoms (CSE). We conclude: (i) that Kr + Kd = 3000ml/wk/L approximates a minimum level of adequate dialysis; (ii) objective measures which index the neurobehavioural syndrome of clinical uraemia detect inadequate (reduced) dialysis.
mesh_terms: D000328:Adult; D004569:Electroencephalography; D006801:Humans; D007676:Kidney Failure, Chronic / Q000175:diagnosis / Q000628:therapy* / Q000652:urine; D008568:Memory; D008875:Middle Aged; D009461:Neurologic Manifestations; D011581:Psychological Tests; D011930:Reaction Time; D006435:Renal Dialysis; D012647:Self-Assessment; D014508:Urea / Q000652:urine
chemical_list: D014508:Urea