The catch with urine: A justification for ultrasound-guided suprapubic tap in the NICU

Abstract

A high index of suspicion is required for urinary tract infections (UTI) detection in the neonatal intensive care unit (1). Catching urine samples in sick children has been a longstanding clinical problem. In febrile children aged 2 to 36 months of life, the Canadian Paediatric Society recommends a bagged specimen for screening purposes only (2). Suspected infections based on bagged samples require follow-up by either clean catch, urethral catheterization, or suprapubic aspiration (SPA). Despite a higher contamination rate of 62.8% compared to 9.1% in catheter samples (3), in an Ontario community hospital audit, 65.7% of UTI diagnoses <3 years were based on bagged samples, in 73.9% without confirmation (4). Catheter samples in the neonatal intensive care unit may be difficult to obtain due to patient size, and results are often unreliable due to contamination. It is paramount to include a urine sample in addition to blood and spinal fluid for late-onset sepsis evaluations in infants >72 hours of life. Clinical signs are often nonspecific and unreliable in neonates (1), making UTIs arguably underdiagnosed. The inability to promptly obtain urine may delay antibiotics, or lead to antibiotics being started before obtaining a urine sample. Urine is rendered sterile by a single dose of an effective antibiotic.