Urinary flow patterns of healthy newborn males.

Purpose: We assessed urinary flow patterns in newborn males using ultrasound flow probes.

Materials And Methods: Specifically customized ultrasound flow probes connected to a flowmeter were mounted on the penis of 30 newborn males. Flow data together with signals from a silent diaper alarm were sampled to a personal computer, and the flow curves were assessed with regard to configuration, maximum flow rate and voided volume. Studies were performed under the surveillance of a nurse, who together with the parents registered episodes of breast-feeding and periods of sleep and arousal, which were rated on a visual analogue scale and converted to percentages with 0% representing quiet sleep and 100% representing the fully awake state. Data were analyzed using the Kruskal-Wallis test and are presented as median (range). A p value of less than 0.05 was considered significant.

Results: The data from 23 neonates were applicable for analysis, and a total of 61 flow assessments were completed. Configuration was bell-shaped in 57% of the studies, interrupted in 18%, staccato in 8%, plateau in 5%, tower flow in 3% and "spike-dome" in 8%. Median voided volume was 10.6 ml (range 1.4 to 65.0) and median maximum flow rate was 2.3 ml per second (0.5 to 11.9). During all but 3 voids the neonates exhibited some degree of arousal. We found no significant correlation between curve configuration and voided volume, maximum flow rate or state of arousal.

Conclusions: Urinary flow curves in newborn males consisted of a known repertoire of configurations, in addition to a "spike-dome" shape not previously described. Of the assessments 34% were dyscoordinated. Voiding tended to occur in the awake state.