Does the use of volumetric bladder ultrasound improve the success rate of suprapubic aspiration of urine?

OBJECTIVE: To determine whether a volumetric bladder scanner can improve the success rate of suprapubic aspiration and whether there is an optimal volume of urine required in the bladder before suprapubic aspiration should be attempted.

DESIGN: Two-phase prospective study.

SETTING: The emergency department of a tertiary children's hospital.

SUBJECTS: Children younger than 2 years who required an uncontaminated urine specimen for microscopy and culture.

METHODS: In phase one, all patients had an ultrasound followed by suprapubic aspiration. In phase two, patients were randomized to either ultrasound or no ultrasound.

RESULTS: In phase one, 37 subjects had ultrasound measurement prior to attempting suprapubic aspiration; 28 of 31 (90%) had successful suprapubic aspiration when a minimum volume of 10 mL was detected on ultrasound and no 0-mL readings were encountered. In phase two, the overall success rate of obtaining urine with the aid of the bladder scanner was 31 of 39 subjects (79%), compared with 16 of 36 subjects (44%) without ultrasound. Ultrasound was also useful in deferring an attempt when less than 10 mL of urine was noted on the scan.

CONCLUSIONS: The volumetric bladder scanner is a rapid, safe, and accurate device that, in this study, greatly improved the success rate of suprapubic aspiration in small children. It also helped to avoid time delays or multiple blind attempts at suprapubic aspiration by predicting volumes at which suprapubic aspiration should or should not be attempted.