Utility of bedside bladder ultrasound before urethral catheterization in young children

Abstract

Background: Urethral catheterization is the method of choice for obtaining samples for urine culture and urine analysis in infants. Before the procedure, there is little certainty of the presence or amount of urine in the bladder. Consequently, this relatively invasive and uncomfortable procedure often needs to be repeated. The newly available technology of portable ultrasound may be useful in reducing the number of unsuccessful procedures.

Objective: To investigate the utility of bedside ultrasound of the bladder performed by pediatric emergency medicine physicians before catheterization in reducing the number of unsuccessful attempts.

Methods: A prospective, 2-phase study was performed in the setting of an urban pediatric emergency department from August 2003 to February 2004. Children who were between the ages of 0 and 24 months were enrolled. During the observation phase, the amount of urine obtained during the first catheterization was recorded for each patient. During the intervention period, a rapid bedside ultrasound of the bladder was performed by a pediatric emergency medicine physician immediately before urethral catheterization. When a sufficient amount of urine was seen, catheterization was conducted as usual. Otherwise, catheterization was deferred and repeated ultrasound was performed at 30-minute intervals until sufficient urine was identified. The amount of urine obtained was recorded.

Results: During the observation phase, 136 infants underwent urethral catheterization. Overall, the rate of success during the first attempt, defined as obtaining >2 mL of urine, sufficient for culture and other routine studies, was 72% (95% confidence interval: 66%-78%). A total of 112 subjects were enrolled during the intervention phase. Sufficient urine was identified on the first ultrasound in 76% (n = 85) of the patients. Among these, 98% (n = 83) underwent successful urethral catheterization during the first attempt. Among those in whom insufficient urine was identified initially (n = 27; 24%), subsequent ultrasound revealed sufficient amount in all patients within 90 minutes. Among these, 93% (n = 25) underwent successful urethral catheterization during the first attempt. Overall rate of success of initial urethral catheterization during the intervention phase was 96% (95% confidence interval: 93%-99%). Compared with the success rate during the observation phase, the differences were statistically significant. The results were consistent after being adjusted for gender.

Conclusion: A rapid bedside ultrasound of the bladder performed by pediatric emergency physicians led to an increased success rate of urethral catheterization in children who were younger than 2 years. We were able to avoid repeated invasive testing with a simple noninvasive procedure.