Comparison of two strategies for short dialysis using 1m2 and 2m2 surface area dialysers

Two matched groups of patients were dialysed either thrice weekly on a double re-used Gambro (2m2) for four and a half hours per dialysis (Group A) or thrice weekly five hours per dialysis on a single non re-used Gambro (1m2) (Group B). There was no significant differences in measured parameters of nitrogen retention between the groups, nor did the mean motor nerve conduction velocity alter significantly in any patient. Both groups preferred short dialysis. No manifestations of inadequate dialysis appeared up to 18 months even in bilateral nephrectomised patients of whom there were 2 in each group. Group B experienced significantly fewer hypovolaemic symptoms during dialysis and the single system in thus preferred. The mean dialysis index in Group A was 1.0 and 0.9 in Group B. These results suggest that a dialysis index of 1.0 overestimates dialysis needs.