Suprapubic bladder aspiration

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The physical examination is facing extinction in modern medicine. The Top Ten Forgotten Diagnostic Procedures series was developed as a teaching tool for residents in family medicine to reaffirm the most important examination- based diagnostic procedures, once commonly used in everyday practice. For a complete pdF of the Top Ten Forgotten diagnostic procedures, go to http://dl.dropbox.

com/u/24988253/bookpreview%5B1%5D.pdf.

Top 10 Forgotten Diagnostic Procedures

Suprapubic bladder aspiration

David Ponka

Faisal Baddar

Contraindications

Overlying cellulitis, known urinary anatomic abnor- mality.

Applications

To diagnose lower urinary tract infections when it is not possible to obtain a sample voluntarily or with urethral catheterization.

Equipment necessary

• Local anesthetic (10 mL of 1% lidocaine)

• Needles, if used: 10-cm, 22-gauge spinal needle for localization in adults; 4-cm, 22-gauge needle in pediatric population

• 10-mL syringe

• Sterile urine- and culture-col- lection container

Set-up

This procedure is best done with the patient in the supine position on an examination table. Before the procedure you must identify the bladder by examining the area. If the blad- der cannot be identified, it is

advisable to hydrate the patient and wait until the blad- der can be identified or to use ultrasound guidance if it is available.

Procedure

This is a sterile procedure. An assistant is necessary to immobilize pediatric patients in the frog-leg position.

1. Use an antiseptic solution to clean the suprapubic area, and drape the patient in a sterile fashion.

2. In the midline, anesthetize the skin approximately 5 cm (no more than half this distance in children) above the pubic symphysis. This step is considered optional in the pediatric patient, as it is thought to cause as much pain as the next step.

3. Direct the 22-gauge spinal needle with the obturator in place through the skin at the same insertion point directing slightly caudad in adults (pelvic organ) or slightly cephalad in children (abdominal organ).

Typically, the needle will enter the abdominal bladder after it has been advanced approximately 5 cm (in the adult).

4. Remove the obturator, connect a sterile syringe, and attempt to aspirate urine from the bladder. If none is obtained, advance the needle, with continuous suc- tion on the syringe. If unsuccessful after an additional 5 cm (in the adult), attempt the procedure from step 3 once more. If again unsuccessful, refer to a urologist or attempt using ultrasound guidance.

Evidence and diagnostic confirmation

Our search results revealed numerous studies address- ing suprapubic bladder aspira- tion.^1-4 Although these reach differing conclusions, suprapu- bic bladder aspiration without ultrasound guidance seems to be a reliable method of obtain- ing urine as long as the patient is hydrated, despite ultrasound guidance having a higher suc- cess rate in at least one study (90% vs 64%).¹ There are min- imal risks associated with unguided bladder aspiration.

Another consideration, how- ever, is that suprapubic cath- eterization seems to be more painful than transurethral cath- eterization in infants younger than 2 months.⁵ Diagnostic confirmation is not required, as this is the crite- rion standard test. Ultrasound guidance can be used in the case of an unsuccessful tap.

Dr Ponka is Associate Professor in the Department of Family Medicine at the University of Ottawa in Ontario. Dr Baddar is a staff hospitalist at Pembroke Regional Hospital and a community preceptor in the Department of Family Medicine at the University of Ottawa.

references

1. Ozkan B, Kaya O, Akdak R, Unal O, Kaya D. Suprapubic bladder aspiration with or with- out ultrasound guidance. Clin Pediatr 2000;39(10):625-6.

2. O’Callaghan C, McDougall PN. Successful suprapubic aspiration of urine. Arch Dis Child 1987;62(10):1072-3.

3. Kiernan SC, Pinckert TL, Keszler M. Ultrasound guidance of suprapubic bladder aspira- tion in neonates. J Pediatr 1993;123(5):789-91.

4. Chu RW, Wong YC, Luk SH, Wong SN. Comparing suprapubic urine aspiration under real-time ultrasound guidance with conventional blind aspiration. Acta Paediatr 2002;91(5):512-6.

5. Kozer E, Rosenbloom E, Goldman D, Lavy G, Rosenfeld N, Goldman M. Pain in infants who are younger than 2 months during suprapubic aspiration and transurethral bladder catheterization. Pediatrics 2006;118(1):e51-6.