26: Bladder Catheterization

1. To collect a urine specimen when a clean-catch specimen cannot be obtained or is unsatisfactory or a suprapubic aspiration cannot be performed. Bladder catheterization is an alternative to suprapubic aspiration but is not the method of first choice. It has a higher false-positive rate than suprapubic aspiration and it can also introduce bacteria and cause a urinary tract infection (UTI).

2. To monitor urinary output, relieve urinary retention, or to instill contrast to obtain a cystogram or voiding cystourethrogram.

3. To determine a bladder residual urine volume.

Sterile gloves, cotton balls, povidone-iodine solution, sterile drapes, lubricant, a sterile collection bottle (often packaged together as a commercial set), and choice of catheter (balloon retention [Foley] catheters are not used in newborns).

1. Use the smallest catheter possible. Recommendations vary widely; it is best to follow your institution's guidelines if available.

2. Urethral catheters. Commercially available sizes: 3.5, 5.0, 6.5, and 8F.

   1. 3.5F for weight <1000 g.

   2. 5F for weight 1000–1800 g.

   3. 6.5F for weight 1800–4000 g.

   4. 8F for weight >4000 g.

3. National Association of Neonatal Nurses (NANN) recommendations. 3.5F for weight <1000 g; 5F for weight 1000–1800 g; 8F for weight >1800 g.

4. Feeding tubes. When used as an alternative, they may increase the risk of trauma or knotting (tubes are softer). 5F feeding tube is sometimes used (not preferred).

5. 3.5F or 5F umbilical catheter. May be used as an alternative: 3.5F for weight <1000 g; 5F for weight >1000 g.

1. When performing catheterization to obtain a specimen, it is best to wait until 1–2 hours after voiding. Ultrasound the bladder to determine the urinary bladder index measurement (product of anteroposterior and transverse diameters, expressed in centimeters squared), which will identify whether there is sufficient urine in the bladder. A urinary bladder index <2.4 cm² means there is lack of urine volume and the catheterization may be unsuccessful. A urinary bladder index >2.4 cm² suggests an adequate urine volume.

2. Pain management. Consider the use of topical and intraurethral lidocaine-enhanced lubricant. Nonpharmacologic pain-reducing methods are also recommended.

3. Male catheterization. See Figure 26–1.

   1. Place the infant supine, with the thighs abducted (frog-leg position).

   2. The newborn male infant has a physiologic phimosis, and the penis cannot be retracted fully. Gently retract the foreskin just enough to expose the meatus; do not force retraction of the foreskin. The meatus can usually be aligned with the opening in the prepuce.

   3. Put on sterile gloves, and drape the area with sterile towels.

   4. Cleanse the penis with povidone-iodine solution. Begin with the meatus and move in a proximal direction. Infant smegma (white discharge from cell shedding) can be gently wiped away.

   5. Place the tip of the catheter in sterile lubricant.

   6. Hold the penis approximately perpendicular to the body to straighten the penile urethra and help prevent false passage. Use a small amount of pressure at the base of the penis to avoid reflex urination.

   7. Advance the catheter until urine appears. Length of insertion in males is generally as follows: weight <750 g, >5 cm; weight >750 g, ∽6 cm. A slight resistance may be felt as the catheter passes the external sphincter; therefore, hold the catheter in place with minimal pressure. Gentle continuous pressure enables the catheter to pass when the sphincter relaxes. Never force the catheter because urethral trauma or false passage can occur.

   8. Collect the urine specimen. If the catheter is to be removed, gently withdraw it. If the catheter is to remain in place, connect it to a closed urinary collection system. It should be taped to the lower abdomen rather than to the leg in males to help decrease stricture formation caused by pressure on the posterior urethra. Contrast can be injected at this point if the catheter has been placed for a radiographic study.

4. Female catheterization. See Figure 26–2.

   1. Supine position technique

      1. Place the infant supine, with the thighs abducted (frog-leg position).

      2. Put on sterile gloves, and drape sterile towels around the labia.

      3. Separate the labia, and cleanse the area around the meatus with povidone-iodine solution. Use anterior-to-posterior strokes to prevent fecal contamination.

      4. Spread the labia with 2 fingers. See Figure 26–2 for landmarks. Lubricate the catheter, and advance it in the urethra until urine appears. General length of insertion: weight <750 g, generally <2.5 cm; weight >750 g, up to 5 cm.

      5. Tape the catheter to the leg if it is to remain in position.

   2. Prone position technique. Used for a female infant who cannot be placed in the supine position (eg, infant with meningomyelocele).

      1. Place the infant prone on blankets so the upper body is elevated as compared with the lower body.

      2. Tape a gauze pad over the anus to avoid contamination. Place sterile drapes.

      3. Then proceed as for supine position.

   3. If urine does not appear in the catheter, the catheter may be in the vagina. Check the catheter position and replace if necessary.

Once urine has been obtained and flow has stopped, gently withdraw the catheter. Observe for urine output.

1. Infection. There is a risk of introducing bacteria into the urinary tract and then the bloodstream. Sterile technique is necessary to help prevent infection. “In-and out” catheterization carries a small (<5%) risk of urinary tract infection. The longer a catheter is left in place, the greater is the infection risk. The risk of UTI is high in catheterized patients. Infections that can occur include sepsis, cystitis, pyelonephritis, urethritis, and epididymitis.

2. Trauma to the urethra or the bladder. Urethral tear, urethral false passage, erosion, stricture, meatal stenosis, or bladder injury (perforation) is more common in males. Minimize by adequately lubricating the catheter and stretching the penis to straighten the male urethra. Never force the catheter if resistance is felt. Use the smallest catheter possible, and advance only until urine is obtained.

3. Hematuria. Hematuria is usually transient but may require irrigation with normal saline solution. Gross hematuria on insertion may indicate a false passage.

4. Urethral stricture. More common in males. It is usually caused by a catheter that is too large or by prolonged or traumatic catheterization. In males, taping the catheter to the anterior abdominal wall helps decrease the pressure on the posterior urethra.

5. Urinary retention. Secondary to urethral edema.

6. Catheter knot. Rare but can happen if the catheter advances too far and is more common if feeding tubes are used. Insert only enough to obtain urine and never force a catheter. Using appropriate lengths based on age and sex may help prevent this complication. If this occurs, a urology consultation may be necessary.

7. Malpositioned catheter. The catheter can be accidently placed in the vagina. If this happens during cystography, the vagina can mimic the bladder. The clue to this is that fluid is in the peritoneal cavity (contrast material flowed through the uterus and fallopian tubes into the peritoneal cavity).

8. Obstructive bilateral hydroureteronephrosis. Rare.