Ultrasonographic Bladder Parameters forSuccessful Suprapubic Bladder Aspiration

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