Point-of-care ultrasound before attempting clean-catch urine collection in infants: a randomized controlled trial

Objective: A new non-invasive bladder stimulation technique has been described to obtain clean-catch urine specimens in infants. This study aimed to evaluate if point-of-care ultrasound (POCUS) guided feeding protocol to measure bladder volume prior to stimulation techniques improves clean-catch urine collection success. Methods: A prospective randomized controlled trial study was conducted in a tertiary care pediatric emergency department. Infants aged less than 6 months needing a urine sample were randomized to either POCUS group or feeding group (standard procedure) before performing a standardized clean-catch urine stimulation technique. In the POCUS group, a feeding period was permitted if the bladder width was less than 2 cm, otherwise the clean-catch urine was performed immediately. The primary outcome was the success of the procedure defined by the collection of at least 2 mL of urine, obtained within 300 seconds of bladder stimulation manoeuvres. It was estimated that the recruitment of 200 children was necessary to yield 80% power to identify an improvement of 20% in the success rate. Results: Atotal of 201 infants were included. The procedure was not more successful in the POCUS group (48%) compared to the feeding group (54%) (Difference: 6.5%; 95% CI:-7.3 to 19.8%). The mean time to collect urine samples from randomization to sample collection was not different between the two groups. Conclusions: Our study failed to show a benefit of using POCUS to improve the success rate of stimulated clean-catch urine. Moreover, the importance of the feeding period prior to clean-catch urine manoeuvres should be evaluated further.