Ultrasonographic Bladder Parameters for Successful Suprapubic Bladder Aspiration

Baek, Sung Chul; Koo, Hoe Kyoung; Kim, Cheol Hong; Kim, Kyung Bum; Lee, Hyun Hee; Choi, Byung Min; Yoo, Kee Hwan; Hong, Young Suk; Han, Dong Gwan

Abstract

PURPOSE
Suprapubic bladder aspiration(SBA) is a widely accepted method of obtaining sterile urine for culture in neonates but has a relatively low success rate and a few serious complications during SBA procedure. To improve the chance of obtaining urine, we determined the ultrasonographic bladder parameters(diameters and volume) to confirm that the bladder is adequately distended for successful aspiration of urine.
METHODS
In 94 newborn infants who required sterile collection of urine, ultrasonographic examination and SBA procedure were carried out. On the patient's suprapubic area, the maximal cephalocaudal and anteroposterior diameters were measured by sagittal scanning, and the maximal anteroposterior and transverse diameters by transverse scanning. Bladder volume was calculated using the formula for elliptic volume, and then urine was aspirated to maximum of 10 mL and the amount of urine aspirated was recorded.
RESULTS
Sufficient urine for culture(>1 mL) was obtained by SBA in 86(91.5%) of 94 infants. In the sagittal view, when the cephalocaudal diameter of the bladder was greater than 20 mm and the anteroposterior diameter was greater than 15 mm, the success rate was 100%. The cephalocaudal diameter of the bladder in sagittal view showed a more significant positive correlation with aspirated urine amount(r=0.65, P<0.001).
CONCLUSION
The ultrasonographic sagittal view improved the success rate of SBA in neonates. A SBA was more likely to be successful when the cephalocaudal diameter of the bladder was above 20 mm and the anteroposterior diameter was above 15 mm.