Adequacy of dialysis with tidal and continuous cycling peritoneal dialysis in children.

BACKGROUND Today the major outcome measure for peritoneal dialysis is adequacy. We seek the optimal dialysis modality and prescription for each patient. Tidal dialysis (TPD) was introduced in 1990 to increase efficacy. However, studies with TPD have been inconsistent, and results in small children are lacking. METHODS Nine patients under and eight patients over 5 years of age who were undergoing or starting maintenance peritoneal dialysis (PD) were studied. Patients were dialysed with TPD and with continuous cycling PD (CCPD), each for 6 months. To optimize TPD and CCPD modalities, we recorded urea K(t)/V, creatinine clearance (CrCl), peritoneal membrane capacity, clinical examination, biochemical values and nutrition. RESULTS The mean nightly dialysate flow rate was significantly higher with TPD than with CCPD (46.4+/-3.7 vs 32.7+/-4.6 ml/kg/h, P:<0.001). Mean total CrCl at the baseline was significantly higher with TPD (79. 3+/-18.5 vs 72.5+/-16.0, P:=0.02), but urea K(t)/V was similar (3. 5+/-0.5 vs 3.3+/-0.4, P:=0.28). Urea K(t)/V and CrCl were higher during TPD in patients with high peritoneal membrane permeability, but similar in patients with high-average membrane permeability. Urea K:(t)/V and CrCl in CCPD and TPD did not differ significantly in the age groups. Nor did the incidence of hypertension differ in CCPD and TPD, despite a significantly lower glucose concentration during TPD. CONCLUSIONS Both TPD and CCPD provide adequate dialysis for paediatric patients under and over 5 years of age. Because of higher costs, we recommend TPD only for paediatric patients with high membrane permeability and reduced ultrafiltration or with mechanical outflow problems or outflow pain.