Randomized cross-over comparison of double mini-PET with standard versus adapted dwell volumes and dwell times in children on chronic peritoneal dialysis.

Background: Automated peritoneal dialysis (APD) consists of dwells with the same dwell volume and time. New cyclers allow modification of time and volume to prescribe adapted APD (AAPD), i.e., a series of short, small dwells followed by long, large dwells. Safety, efficacy, and underlying mechanisms of AAPD in children are uncertain.

Methods: Two double mini-PET were performed in randomized sequence. The standard test consisted of two identical cycles (fill volume 1000 ml/m², 75 min) and the adapted test of a short, small cycle (600 ml/m² BSA, 30 min) followed by a long, large cycle (1400 ml/m², 120 min). Solute and water fluxes were quantified together with intraperitoneal pressure (IPP). Nine pediatric PD patients (5-21 years) were treated per protocol.

Results: Residual dialysate volume was 422 ± 190 ml/m² BSA. There were no differences in ultrafiltration rates, glucose uptake, and creatinine, urea, and electrolyte clearances with the adapted and standard double mini-PET, despite identical cumulative dialysate volume and time. IPP varied by 1.7 ± 3.4 (range -2 to 9) cm H₂O with a drained volume of 1123 ± 386 and 1159 ± 210 ml/m² BSA for each standard dwell. IPP decreased from 1.9 with small volume to 1.0 cm H₂O /m²/100 ml with large volume dwells (p < 0.001) and was above 14 cm H₂O in 21 out of 63 measurements.

Conclusion: Within the limitation of small patient numbers, this proof-of-concept study suggests similar ultrafiltration and clearance rates with a single adapted versus standard double mini-PET. High residual dialysate volumes and high IPPs highlight the challenges of AAPD prescription in children.