Urinary flow patterns in premature males

Purpose: We sought to assess urinary flow patterns in premature males using ultrasound flow probes.

Materials and methods: Specifically customized ultrasound flow probes connected to a flowmeter were mounted on the penis of 29 premature males (median gestational age 31.3 weeks). Flow data were sampled to a personal computer and flow curves were assessed with regard to configuration, maximum flow rate and voided volume. Examinations were performed at the neonatal unit within the ambient environment of the incubators and under the surveillance of a study nurse for a period of 4 hours.

Results: Data from 25 boys (98 voids) were applicable for analysis. Flow curve configuration was bell shaped in 48% of patients, interrupted in 44%, staccato in 6% and plateau in 2%. Overall 59% of flows were dyscoordinated, and no patient with more than 1 assessable void had exclusively coordinated flows. Median voided volume was 3.9 ml (range 0.6 to 25.2), median maximum flow rate was 1.0 ml per second (0.3 to 10.0) and median number of voids per hour was 1.0 (0.2 to 3.6). No correlation was found between flow curve configuration and maximum flow rate (p = 0.32). However, plateau shaped curves were associated with larger voided volumes (p = 0.05).

Conclusions: Urinary flow pattern assessment in preterm males is possible and reveals a high degree of dyscoordination. There is a tendency toward a mixture of coordinated and dyscoordinated flow patterns in the same individual.