Assessing bladder capacity in children: is it feasible at all?

The aim of the study was to assess correlations between body parameters and bladder capacity in healthy schoolboys and schoolgirls. On the basis of those anthropometric data functional bladder capacity (FBC) in children was estimated.

The questionnaires were sent to 1,055 parents of children aged from 6 to 14 years. Voided volumes were assessed during uroflowmetry, which was performed under typical conditions in separate rooms (Urodyn 1,000, Dantec, Skovlunde, Denmark). Residual volume was measured thereafter. Precise anthropometric parameters were obtained in standing the position. Children with dysfunctional problems, those who voided less than 100 ml and those with residual volumes > 5% of voided volume were excluded. Statistical analysis was done on the basis of the results gathered from 288 children. Pearson's correlation coefficient between body measurements and voided volume was calculated (P < 0.05). Regression modeling was used to propose the best formula for calculating FBC in children.

Mean FBC is higher in girls than in boys (P < 0.05). The correlation between FBC and flow parameters was found (0.3 < "r" < 0.5). The value of the coefficient indicates loose relationship. We revealed correlation between weight, height, and length of the trunk, pelvic dimension and FBC. The best mathematical equation to estimate FBC in children based on the body measurements fits to 54% of population (FBC = -268.4 + 7.38 x flow time + 3.15 x suprasteral height + 1.25 x thickness of fat fold.