Standards for ultrasound guidance of suprapubic bladder aspiration

We performed a prospective study of 40 infants with suspended urinary tract infection to determine standards for ultrasound guidance of suprapubic bladder aspiration (SBA). Only transverse bladder diameter showed a significant correlation with bladder volume (r = 0.83, P < 0.001). Urine was obtained in 36 patients (90%). The mean transverse diameter was 4.4 +/- 0.8 cm (range 3-6.1 cm). In the 4 patients (10%) in whom urine was not obtained, the transverse diameter was 3.2 +/- 0.2 cm (range 2.9-3.5 cm). Our findings indicate that a SBA is more likely to be successful when the transverse diameter is above 3.5 cm, whereas when the diameter is lower than 3 cm the procedure is less likely to be successful.