A method to assess efficacy of CAPD: preliminary results

Adequacy of dialysis is a primary concern when caring for patients undergoing continuous peritoneal dialysis (CAPD). To determine objectively the efficacy of CAPD, the use of an 'efficacy number' (EN) calculated from the data obtained in a peritoneal equilibration test (PET) for creatinine (cr) is proposed: EN = [cr(D/P) x V24] divided by ACPPD3 Where, cr(D/P) is PET-derived dialysate/plasma ratio for creatinine at 4 hrs; V24 is the volume of exchanges (L) prescribed for 24 hrs; ACPPD is adjusted creatinine production based on daily dialysate creatinine appearance. PET were performed and the EN calculated in two groups of CAPD patients observed over a 10 month period. One group (n = 8) had a poor clinical outcome in terms of uremic parameters. The EN in this group was 3.85 +/- 0.45 (+/- 1 SD) L/g creatinine/day. The other group (n = 4) was considered well dialyzed and had a good clinical outcome over 10 months. The EN in this group was 6.07 +/- 0.40 L/g creatine/day, p less than 0.001. There was no statistically significant difference between the two groups in regard to sex, age, length of time on dialysis, underlying kidney disease, baseline creatinine, or D/P ratios of creatinine and BUN. The 'efficacy numbers' appears to be more useful than the D/P ratio alone in determining the adequacy of CAPD. A simple to use nomogram is presented which provides guidelines for the clinician to alter the dialysis prescription.