Comparing an additional hour of cycler therapy to an additional midday exchange to achieve adequacy targets

As CAPD patients lose residual renal function, adequate dialysis is frequently impossible to obtain unless the dialysis prescription is changed. For patients already on cycler therapy with a "wet" day, we compared the advantage of adding one hour on the cycler to adding an extra, midday exchange. To compare the two approaches, we used a commercial computer program to optimize solute clearance in 90 patients. Adding one hour of cycler therapy increases Kt/V and creatinine clearance (CrCl) by approximately 6.4%-8%. When a midday exchange is added, the increase in Kt/V and CrCl varies between 17.5% and 21.6%. We conclude that adding an extra, midday exchange always gives a better increase in weekly Kt/V and CrCl than that obtained by adding an extra hour of cycler therapy.