The placement of a cat urinary catheter is a standard procedure that most clinicians are used to performing but some thought should always be given to catheter selection, considering such variables as cat catheter size and catheter material.
Cat catheter size: is bigger always better?
The length and diameter of the feline urinary catheter selected will depend to some extent on patient size together with the length of time that the catheter is anticipated to be left in place.
One study suggested that smaller diameter catheters have been associated with a decreased incidence of urinary obstruction in the 24 hours following catheterisation1 (6.7% cats with 3.5fr catheters re-obstructed compared to 19% with 5fr). However, another study failed to find a link between catheter size and re-obstruction risk,2 so impact of catheter size is not entirely clear and needs further investigation. Nevertheless, when managing obstructive FLUTD, feline urinary catheters should be no larger than 5fr.
Ideal catheter material: soft and atraumatic
The ideal material for a cat urinary catheter should be soft, pliable, and atraumatic. Consideration should also be given to the use of catheters made of material that can be used both for unblocking the feline urethra and ongoing care as repeated catheterisation is likely to be associated with more urethral trauma.
The majority of catheters used in the management of blocked urethra in cats, are made of polypropylene, polytetrafluoroethylene (PTFE) or polyurethane (PUR).
Polypropylene catheters are relatively stiff and while this may make them easier to place, it can increase the risk of urethral trauma especially if excessive force is used. In addition, they are not recommended for indwelling use as they are more irritant.
Polytetrafluoroethylene (PTFE) and polyurethane (PUR) feline urinary catheters are preferable to those made of polypropylene for managing obstructive FLUTD. PTFE and PUR are less irritant than polypropylene and have the advantage that they are firmer at room temperature for unblocking and easier placement but soften at body temperature to increase patient comfort.
Additional feline urinary catheter considerations:
- Bonded hub
Hub and catheter should be bonded together so that they will not separate. With this in mind, catheters without a bonded hub should not be left in situ due to the risk of detachment of the urethral portion.
- Stylet or no stylet?
A stylet will aid placement of a feline urinary catheter but needs to be removed after insertion to reduce the risk of urinary tract trauma and for patient comfort. Catheters without a stylet may need to be more rigid for placement and therefore uncomfortable while in situ.
- Radiopacity
Confirming correct catheter placement, especially for longer term use, is important. Pre-measuring catheters prior to insertion is essential but in addition, using catheters that are radiopaque allows radiographic confirmation of correct placement when necessary.
- Atraumatic tip
All urinary catheters should have an atraumatic tip. This is important both for ease of insertion and for reducing the risk of urethral or bladder trauma.
- Suture holes
Where a feline urinary catheter needs to remain in place, whether in the short term during initial stabilisation, or longer term, ease of securing the catheter is an important consideration. Without an effective means of securing, the risk of the catheter becoming dislodged increases, necessitating repeated attempts at catheterisation and an associated increase in risk of urinary tract trauma. Catheters with a suture ring with pre-placed holes provide an effective and user-friendly means of securing.
- Luer lock connection
A catheter with luer lock connection enables secure attachment to a closed collection system, which is important for reducing the risk of urinary tract infection and monitoring urine output.
References
- Hetrick PF, Davidow EB. Initial treatment factors associated with feline urethral obstruction recurrence rate: 192 cases (2004-2010). JAVMA 2013; 243(4):512-519
- Eisenberg BW, Waldrop JE, Allen SE, Brisson JO, Aloisio KM, Horton NJ. Evaluation of risk factors associated with recurrent obstruction in cats treated medically for urethral obstruction. J Am Vet Med Assoc. 2013;243(8):1140-1146
