The use of urinary catheters is a common part of veterinary practice. Indications for urinary catheters include urinary obstruction,
urinary trauma, voiding disorders, urine diversion during or after surgery, or to monitor urine production. Additionally,
catheters are sometimes used to perform contrast radiographic procedures, to collect urine or to collect cells and tissue
samples from the lower urinary tract. Urinary catheters may be passed and removed (intermittent catheterization) or left in
place for variable periods of time (indwelling urinary catheterization). Indwelling catheters are reserved for situations
in which retention of urine or replacement of the catheter would be detrimental to the patient (e.g. severely ill obstructed
cat, urethral trauma, or monitoring of acute renal failure). Urinary catheters described here are typically transurethral
catheters. If the transurethral route is impossible, or a longer term urinary diversion is needed, antepubic catheters can
be placed directly into the urinary bladder through the abdominal wall (cystostomy catheters).
Transurethral catheter placement
One key to successful use of urinary catheters is preparation. Prior to starting the procedure, all the possible supplies
should be gathered:
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Sterile gloves
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Cleansing solution or soapy water
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Gauze pads or cotton balls
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Sterile lubricant (individual packets of sterile lubricant are ideal)
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Flushing solution (sterile saline)
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Syringes to withdraw urine and to save a urine sample
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Syringe to inflate catheter cuff (if using a Foley catheter)
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Bowl for larger volumes of urine
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Appropriate Catheter (plus extras) plus stylet (if appropriate)
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Mosquito forceps
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Drugs for sedation (if needed)
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Speculum and light source (females)
If the catheter is to be left indwelling:
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Tape and/or suture to secure catheter
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Extension line or intravenous fluid administration set
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Collection bag
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Elizabethan collar
The type and size of catheter depends on the patient to be catheterized and the length of catheterization anticipated. Polypropelene
catheters (tomcat and longer urethral catheters) are easy to place because of their stiffness, but are more irritating to
the patient. Small 3.5 French polypropylene catheters (TomCat catheters) are usually used to unobstruct male cats, but softer
infant feeding tubes or specialized catheters can be used for longer term catheterization. Softer red rubber catheters are
often used for male and female dogs and range in size from 3.5-8 French. Polypropelene catheters also can be used for one-time
catheterization. If urethral catheters are to be left in for extended periods, then a Foley catheter may be placed. Foley
catheters have a balloon at the distal tip of the catheter that may be filled with air or water. Once the catheter is inserted
into the urinary bladder, the balloon is filled up and the catheter is pulled caudally to "wedge" the balloon in the area
of the trigone, preventing it from slipping out. Foley catheters are especially useful in female dogs because of their relatively
short urethra.
Urethral catheterization in dogs, especially males, is accomplished more easily than in cats because sedation is not often
required. When placing urethral catheters, it is important to be as clean as possible, and if indwelling urethral catheters
are placed, then it should be done as aseptically as possible. The hair may be clipped away from the vulva in female dogs
and cats or the prepuce in male cats if needed. The area around the penis or vulva should be cleaned with warm soapy water
to minimize inducing iatrogenic bacterial urinary tract infections. Only dilute chlorhexidine solutions or dilute betadine
should be used around the penis or vagina (no alcohol!)
