Four-hour voiding observation: Normative data from term Indian neonates

The four-hour voiding observation is an important non-invasive urodynamic test for infants and young children before toilet training. The study was performed to generate normative data for term Indian neonates.

The study was a descriptive study performed in the Department of Paediatrics of a secondary care hospital in South India with patients having nationwide representation from August 2018 to August 2020. Term neonates, appropriate for gestational age on days 4-14 of life were included. Neonates at risk of oliguria or abnormal bladder functions were excluded. Four-hour voiding observation was performed by direct observation of voids, pre- and post-void diaper weight and measurement of post-void residue (PVR) by ultrasonography using two formulae within five minutes of voiding.

A total of 102 neonates (166 voids) were studied. Important results were (a) Eight neonates did not void; (b) median (fifth-95th percentile) of important test outcomes as follows: voided volume: 15 (7.5-33.5) ml, maximum voided volume (MVV) 16.5 (8.0-38.7) ml, PVR 3.2 (0.5-10.2) ml, PVR% 17.0 (2.9-46.4) % functional bladder capacity 19.7 (9.6-38.0) ml, and diuresis: 1.7 (0.0-5.1) ml/kg/hour; (c) four (4.3%) neonates had one interrupted void each; (d) linear regression yielded the following formulae: MVV (ml) = 8.1019 + 4.8702 ∗Diuresis (ml/kg/hr) and PVR % (max) = 14.2312 + 3.2682∗ Diuresis (ml/kg/hr).

Normative data on the four-hour voiding observation study for Indian term exclusively breast-fed neonates are reported.