25: Bladder Aspiration (Suprapubic Urine Collection)

I. INDICATION

To obtain urine for culture when a less invasive technique is not possible. It is the most accurate and preferred culture source for infants and children <2 years of age when compared with urethral catheterization and bag urine specimens. Any bacteria or growth on a suprapubic culture is considered abnormal and requires treatment. Other common terms include suprapubic bladder aspiration (SBA), suprapubic aspiration (SPA), and bladder tap.

II. EQUIPMENT

Safety-engineered needle: 23- or 25-gauge 1-inch needle or 21- to 22-gauge 1.5-inch needle (large infant) or 23-gauge butterfly (for preemie) attached to a 3-mL syringe, sterile gloves, povidone-iodine solution, 4 × 4 gauze pads, gloves, and sterile container; transillumination light source or portable ultrasound recommended.

III. PROCEDURE

1. Contraindications. Empty bladder, thrombocytopenia, presence of abdominal distension, bleeding disorders, genitourinary anomalies, cellulitis at the site, after recent lower abdominal or urologic surgery.

2. Note that before the age of 2 years, the bladder is an abdominal organ and this makes the procedure easier. After 2 years of age, the bladder moves into the pelvis.

3. Verify that voiding has not occurred within the previous hour so there will be enough urine in the bladder for the procedure. Has there been a recent wet diaper? Is the diaper wet now?

   1. Palpate or percuss the bladder. Dullness to percussion 2 fingers above the pubic symphysis suggests urine in the bladder. The neonatal bladder extends above the pubic symphysis as it fills.

   2. Transillumination can determine bladder height and verify the presence of urine. With the lights dim, the transillumination source is pointed at the bladder. The area will glow red if urine is present. (See Chapter 40).

   3. Ultrasound of the bladder can help determine the size and location of the bladder and the volume of urine in the bladder. Portable ultrasound can significantly improve the diagnostic yield; a minimum volume on ultrasound of 10 mL is associated with a 90% successful bladder aspiration. If the cephalocaudal diameter of the bladder (sagittal view) is >20 mm and the anteroposterior diameter is >15 mm, the success rate approaches 100%.

4. Pain management. This procedure is significantly more painful than transurethral catheterization (as evidenced by brow bulging in one study). Nonpharmacologic pain procedures can be used. EMLA (eutectic mixture of lidocaine and prilocaine) alone or EMLA plus local injection of lidocaine can be used. In one study EMLA use 1 hour before the suprapubic aspiration was found to reduce pain scores more than without EMLA. Local injection of lidocaine often turns this from a “one stick” to a “two stick” procedure.

5. Bedside ultrasonography if available can be used to help guide needle insertion and puncture of the bladder wall. When used, fewer needle insertions are necessary.

6. An assistant should hold the infant in a supine position with the legs in the frog-leg position.

7. Locate the site of bladder puncture, which is ∼1–2 cm above ...