Residual peritoneal volume and body size in children on peritoneal dialysis

Residual peritoneal volume may play an important role in dialysis efficacy and abdominal compliance in patients on chronic peritoneal dialysis (CPD). In children on CPD, the relationship between residual peritoneal volume and different measures of body size, as well as the day-to-day variability of residual volume, have not been established. We therefore investigated, on two consecutive days, residual peritoneal volume in 25 children on CPD, using the dextran dilution technique. Residual volume was linearly correlated with body size. Residual volume was independent of body size when normalised to body surface area, but decreased with increasing body size when normalized to body weight (r = -0.62, p < 0.001). Mean residual volume was 79 +/- 25 mL/m(2), with an intra-individual day-to-day coefficient of variation of 21% +/- 15%. Residual volume was not correlated with the duration of PD, frequency of peritonitis, or peritoneal permeability as estimated by D/P creatinine or D/D-0 glucose. In conclusion, residual peritoneal volume is constant across the pediatric age range when normalized to body surface area. It accounts for approximately 8% of the usual fill volume in patients on CPD. Residual volume is not a major confounder of the transport status estimation obtained by peritoneal equilibration test.