Comparison of symptoms, chemistry, and nerve function to assess adequacy of hernodialysis

To determine whether symptoms of uremia, serum urea, serum creatinine, or nerve function tests provided the most sensitive and reliable index on which to judge the need for hemodialysis, we entered 22 patients in a controlled clinical trial of short or long hemodialysis thrice weekly. Short hemodialysis consisted of 1½ hours for women and 2 hours for men, whereas long dialysis consisted of 3 hours for women and 4 hours for men. Nerve function tests included scored neurologic disability, muscle strength, computerized tests of cutaneous sensation, and nerve conduction studies. Of nine patients in the short hemodialysis group, three remained free of symptoms of uremia, pericarditis developed in two, and pleurisy and ascites developed in one each. Only three could be maintained on the schedule for the full 12 months of the study. In contrast, all 13 patients in the long hemodialysis group remained free of such symptoms and signs, and could be maintained on the schedule for the full study. Despite the difference in duration of dialysis and the clinical response, predialysis urea and creatinine values and tests of nerve function did not provide a clear index of need for dialysis. Even in three patients with unequivocal symptoms of uremia, serial tests failed to show worsening of nerve function. Therefore, predialysis urea and creatinine values and tests of peripheral nerve function do not appear to be sensitive or reliable indices by which the practicing nephrologist can adjust the amount of hernodialysis from day to day. Although tests of nerve function might indicate a need for more hemodialysis when inadequate hemodialysis has been extended for long periods, we did not detect sigdicant differences in scored neurologic findings between the two hemodialysis treatment schedules when our results were projected to the end of a year.