Intraperitoneal pressure in children: fill-volume related and impacted by body mass index.

✦ Objective: Prescription of intraperitoneal volume (IPV) in children on peritoneal dialysis (PD) should be individualized in order to optimize both efficiency and tolerance. Intraperitoneal pressure (IPP) can be used as an objective assessment of IPV. Despite IPP being correlated with IPV, there is an important interindividual variability presumed to be secondary to other implicated factors. ✦ Design: Over the past 2 years, we conducted a prospective study in our patients on PD (N= 17). For each child, we recorded, at every third month of follow-up, IPV (in milliliters per square meter body surface area), age, gender, body mass index (BMI), and IPP (measured as centimeters of water), collecting a total of 53 data points. ✦ Results: There was a positive correlation between IPV and IPP (r = 0.36), but this correlation was weak in contrast to the strong correlation noted between BMI and IPP (r= 0.82). Age had a different influence on IPP: in the younger-aged group (< 2 years), IPP decreased with age; in the older-aged group (≥ 2 years), IPP increased with age. In some infants, we noted a paradoxical result: a low IPV with a high IPP. ✦ Conclusions:The strong correlation noted between IPP and BMI gives a better understanding of the interindividual variability of the previously described unique relationship between IPP and IPV. The more obese the child (i.e., the higher the BMI), the higher is his IPP for a fixed IPV.