Urethral Catheterization

Univ. of Minnesota, College of Veterinary Medicine, Clinical Skills - Year 3

Indications

1. Diagnostic catheterization may be indicated to:
  • Collect bladder urine for urinalysis of bacterial culture. There are times when catheterization is the only reliable means of obtaining a sample for diagnostic study.
  • Collect accurately timed volumes of urine for renal function studies.
  • Monitor urine output in severely ill patients, patients with urinary obstruction, or following urologic surgery.
  • Instill contrast media for contrast radiography.
  • Evaluate the urethral lumen for calculi, space-occupying lesions or strictures.
  • Determine the volume of residual urine in patients with suspected neurogenic incontinence.
2. Therapeutic catheterization may be indicated to:
  • Relieve obstruction to urine flow
  • Instill medications into the urinary bladder
  • Facilitate surgical repair of the urethra or surrounding structures.

Complications

1. Trauma
  • Trauma can usually be avoided by using a smooth flexible catheter and good technique
  • Hematuria caused by catheterization may indicate poor equipment or technique. However, the disease process may have markedly increased the vascular supply to the bladder and/or urethra. Consider cystocentisis if this is suspected.
  • Hematuria is usually self-limiting but may interfere with interpretation of urinalysis results.
  • Trauma may predispose the patient to bacterial infection since it damages the normal host-defense mechanisms.
2. Infection
  • The distal urethra, vagina and prepuce normally contain bacteria (Staphylococci, Streptococci and Gram negative organisms) and mycoplama.
  • Urine in the kidneys, ureters, and urinary bladder of normal dogs and cats is usually sterile.
  • Even careful catheterization may cause infection (although the risk is low) because these bacteria are carried into the bladder.
  • To minimize the risk, consider cystocentesis for patients with pre-existing disease in the urethra and/or urinary bladder.
  • Avoid repeated catheterization and indwelling catheterization because there is an increased risk of iatrogenic infection with these procedures.

Equipment

Urinary catheters
Equipment needed for a male dog:
  • Cotton or gauze sponges
  • Povidone-iodine surgical scrub
  • Sterile surgical gloves
  • Sterilized aqueous lubricant
  • 4 to 10 French sterile urinary catheter (use the smallest diameter possible)
  • Sterile container for urine collection
Additional equipment needed for a female dog:
  • 4 to 10 French sterile urinary catheter (use the smallest diameter possible)
  • Light source
  • Sterile vaginal speculum (or otoscope cone)
Additional equipment needed for male cats:
  • 3 to 5 French sterile urinary catheter (use the smallest diameter possible) with side holes and a closed tip
  • Drugs for sedation or anesthesia (often needed)
Additional equipment needed for female cats:
  • 3 to 5 French sterile urinary catheter (use the smallest diameter possible)
  • Drugs for sedation or anesthesia (often needed)

Procedure

Preparation
Cleanse the area (dog) Cleanse the area (cat) Urinary catheter
  1. An assistant will be required for restraint and help with the procedure.
  2. Gently cleanse the area around the prepuce or vulva with povidone-iodine scrub.
  3. Select the appropriate size sterile, flexible urinary catheter and examine it for any defects that might cause trauma or interfere with the procedure
  4. Wash hands thoroughly and put on sterile gloves (with experience you may be able to maintain sterility without gloves by holding the catheter through its plastic sleeve and slowly advancing it out of the sleeve)
Male Dog
Premeasure the catheter Place in lateral recumbency Insert the end of the catheter into the external urethral orifice Catch urine in sterile collection container
2. Premeasure catheter 3. Place in lateral recumbency 7. Insert catheter 11. Gently aspirate
  1. Follow steps 1-4 of Preparation.
  2. Premeasure the length of the catheter that will need to be advanced by holding it along side the patient and estimating the distance from the external urethral orifice to the bladder neck. If the catheter is advanced too far it can fold back on itself or cause trauma to the bladder wall.
  3. Have your assistant place the dog in lateral recumbency with the upper hind leg held out of the way in abduction.
  4. Ask your assistant to retract the prepuce to expose the tip of the penis and carefully maintain retraction throughout the procedure to prevent contamination of the catheter.
  5. The assistant should then cleanse the tip of the penis with a mild soap solution.
  6. Lubricate the end of the catheter with sterile lubricant
  7. Insert the end of the catheter into the external urethral orifice and advance it. This can be difficult, especially at the level of the os penis and again at the site where the urethra curves around the ischial arch.
  8. Be careful to prevent contamination of the rest of the catheter by keeping it within the sterile plastic sleeve or holding within the other (sterile gloved) hand.
  9. Insert the catheter to the premeasured length.
  10. Catch urine in sterile collection container.
  11. You may need to attach a syringe to the end of the catheter and gently aspirate to withdraw urine. Do not manually compress the bladder as this can cause traumatic injury.
Female Dog
Introduce the speculum Introduce the speculum Insert the speculum Blind catheterization
4. Introduce the speculum 4. Introduce the speculum 4. Introduce the speculum 6. Blind catheterization
  1. Follow steps 1-4 of Preparation.
  2. Have your assistant restrain the patient in a standing position with the tail held to the side.
  3. Lubricate the end of the catheter with sterile lubricant
  4. Introduce the speculum into the vagina in a dorsal and cranial direction (to avoid the clitoral fossa ventrally). Direct your assistant on how hold the light source (if you are using an otoscope as the speculum then you will not need an additional light source).
  5. Visualize the urethral orifice on the floor of the vagina. It will be located about 1-2 inches internally.
  6. In very small patients it may be difficult to visualize the urethral orifice. In this case "blind catheterization" may be performed. Insert the cather above the clitoral fossa and then advance it in a cranioventral direction. The tip of the catheter should be slowly advanced along the ventral midline of the vaginal floor. If you encounter resistance, you may have encountered the vaginal fornix. Withdraw the catheter to a position just cranial to the clitoral fossa and try again.
  7. Insert the end of the catheter into the urethral orifice and advance it 3-6 inches or until urine starts to flow through the catheter.
  8. Catch urine in sterile collection container.
  9. You may need to attach a syringe to the end of the catheter and gently aspirate to withdraw urine. Do not manually compress the bladder as this can cause traumatic injury.
Male Cat
Extrude the penis Insert the catheter Attach a syringe
4. Extrude the penis 5. Insert the catheter 7. Attach a syringe
  1. Follow steps 1-4 of Preparation.
  2. Your assistant should restrain the cat in lateral recumbency and hold the tail out of the way. In many instances, the patient must be sedated or anesthetized.
  3. Lubricate the end of the catheter.
  4. Use your non-dominant hand to fully extrude the penis from the prepuce. Push the penis dorsally until it is parallel with the spine to straighten the urethra.
  5. Insert the end of the catheter into the urethral orifice and advance it to the lumen of the urinary bladder. Your may encounter resistance because of the curvature of the urethra adjacent to the bony pelvis, skeletal muscle contraction, or a urethral obstruction. Injecting small amounts of sterile saline through the catheter may help to distend the urethral lumen.
  6. Catch urine in sterile collection container.
  7. You may need to attach a syringe to the end of the catheter and gently aspirate to withdraw urine. Do not manually compress the bladder as this can cause traumatic injury.
Female Cat
  1. Follow steps 1-4 of Preparation.
  2. Your assistant should restrain the cat in lateral recumbency and hold the tail out of the way. In many instances, the patient must be sedated or anesthetized.
  3. Lubricate the end of the catheter with sterile lubricant
  4. Carefully insert the tip of the catheter into the external urethral orifice located on the midline of the vaginal floor and advance it to the lumen of the urinary bladder.
  5. Catch urine in sterile collection container.
  6. You may need to attach a syringe to the end of the catheter and gently aspirate to withdraw urine. Do not manually compress the bladder as this can cause traumatic injury.