Urinary Catheterization

Background and History

Disease processes that require urinary bladder catheterization have existed since ancient times. Urethral strictures, bladder stones, and prostatism are among the first diseases that necessitated urinary bladder decompression by catheterization. The approach to urinary catheterization remains the same today as it was in ancient times. It is the technique of passing a hollow tube through the urethra into the urinary bladder for purposes of circumventing an obstructed urinary bladder or obtaining a sample of urine for analysis, or both.

The first known urologic instruments would be considered somewhat barbaric by today's standards. Ancient and medieval “urologists-lithot-omists” used perineal incision and metal and glass tubes to circumvent urinary obstruction. Today's approach often uses a local anesthetic and urethral catheters made of rubber, latex, polytetrafluoroethylene (Teflon), or silicone polymers. Urethral catheterization is currently used for relief of bladder outlet obstruction or when measurement of urinary output must be precise (e.g., in multiple trauma, surgery, intensive care, renal failure).

Indications

Reasons for passing a catheter into the urinary bladder are many. The most common uses of bladder catheterization are the following:

• To obtain a sterile urine sample, especially in the female patient

• To monitor urinary output closely in critically ill patients

• To facilitate urinary drainage in patients who are incapacitated (stroke, advanced Alzheimer disease, spinal transection, etc.)

• To bypass obstructive processes in the urethra, prostate, or bladder neck caused by disease or trauma until surgical repair can be performed

• To hold urethral skin grafts in place after urethral stricture repair

• To act as a traction device for the purpose of controlling bleeding after prostate surgery

• Specialized three-way Foley catheters are used after bladder or prostate surgery to allow continuous bladder irrigation. Continuous irrigation and drainage help prevent the formation of blood clots, which can occlude a catheter and cause bladder obstruction. Three-way Foley catheters also allow easier evacuation of formed blood clots ( Figure 70-1-1 ).

  

The main reasons for using the one-time, straight, or Robinson catheter are as follows:

• To obtain a sterile urine sample or to decompress a distended bladder caused by an acute obstructive process

• As a protocol of intermittent catheterization in persons with neurogenic bladder: Catheterizing patients with neurogenic bladder at regular intervals with the Robinson catheter facilitates complete bladder emptying, routine urine sampling, and bladder training. After a time, some of these patients may be able to decrease the frequency of their catheterization, regain complete bladder control, or both.

• To deliver topical antineoplastic medication to the bladder in patients who have bladder cancer or deliver other topical medication to patients who suffer from interstitial cystitis

• Assess postvoid residual urine through catheterization; however, this is being replaced by postvoid ultrasound of the bladder

Contraindications

The only contraindication to inserting a catheter (either Robinson or Foley) is the appearance of blood at the urethral meatus in a patient who has sustained pelvic trauma. This finding can be an indication that the urethra has been partially or totally transected. Attempting to pass a catheter in this situation could cause a partial urethral transection to become total. A urologist should be consulted when blood at the urethral meatus is present in a patient with pelvic trauma. Allergy to materials used in the procedure, such as latex, rubber, tape, and lubricants, is also a contraindication.

Potential Complications

Most of the complications with catheterization are seen in the male patient. Female patients rarely have urethral strictures, caused by traumatic catheterization. Because the female urethra is comparatively short, false passages are rarely created. Complications can include the following:

• Urethral dilation resulting from placement of long-term indwelling Foley catheter in women. Leaking can occur because of bladder spasm. Instead of treating the spasm, progressively larger diameter catheters are placed, causing urethral dilation and continuation of leaking.

• Urinary structural trauma may occur as a result of catheterization.

• Urinary tract infection may occur as a result of organisms on the catheter or transmitted during the procedure.

• Inflammation of the urinary tract may occur secondary to the procedure.

• Catheterizing a male patient with urethral stricture disease, bladder neck contracture, or an enlarged prostate; this may present some technical difficulties for the unsuspecting health care provider

• Passage of a Robinson or Foley catheter in a patient with urethral stricture disease or an enlarged prostate. This increases the danger of creating false passages in the urethra if excessive force is applied when resistance is met during the catheterization. The mechanism of injury occurs when the obstructive process deflects the catheter into the side wall of the urethra. If the clinician meets these types of obstructive processes and continues to apply excessive pressure in an attempt to bypass the blockage, the catheter can act like a drill and undermine the lining of the urethra, thus creating a false passage. The worst scenario in this situation would be pushing the catheter completely through the urethra into the surrounding tissue. This results in copious bleeding from the urethra and creates the possibility of urine and blood extravasating into the surrounding tissues.

• Having the catheter double back or make a U-turn at the site of obstruction. It is not uncommon to have the catheter tip reappear at the urethral meatus when a significant obstruction or bladder neck spasm is present.

• Improper securing or taping of the Foley catheter.

• Patient-caused trauma. Patients who are confused can pull out a fully inflated Foley catheter.

Essential Anatomy and Physiology

Urine is produced by the kidneys and transported to the bladder by the ureters, where it is stored for transport through the urethra during urination. Bladder catheterization involves the passage of a mechanical device into the bladder through the urethra. To accomplish this without damage requires an understanding of the anatomy of the lower urinary tract. Figure 70-1-2 illustrates the anatomy in relation to the location at which a urinary catheter would be placed for males and females.

In females, the distance from the distal end of the urethra to the bladder is relatively short (1.5 to 2 inches) and the course through the urethra is relatively unobstructed. Because of this, bladder catheterization in the female patient is typically accomplished faster and with less discomfort than it is in the male patient.

In males, the distance from the distal tip of the urethra to the bladder is longer (typically 6 to 7 inches; however, it can vary considerably) and is more circuitous than in females, thus making catheter insertion potentially more difficult. In males, the path to the bladder typically includes curves that may be encountered while traversing the penis as well as a sharp bend through the prostate. Occasionally, prostatic hypertrophy can make catheter insertion difficult because the pressure of the hypertrophic prostate can add a curvature to the urethra as well as produce urethral obstruction.