Urology HOW TO REMOVE URETHRAL OBSTRUCTION IN CATS the introduction of the olive-tip catheter is accomplished and there is no resistance to the solution, it is gently removed. If an olive-tip catheter is not available a flexible urethral catheter with frontal opening can be used. The tip of a flexible urethral catheter should be lubricated with a sterile water-soluble gel and introduced into the urethra, advancing with rotating movements on its axis and pushing it gently; insertion must be with relative ease (Videos 4 & 5). If the catheter does not advance, check the penis position; remember that it must be pulled in the caudo-dorsal direction to align the urethra, aiming for it to be parallel to the vertebral column, which will facilitate the introduction of the catheter. If, even after this it is not possible to advance the catheter, it is necessary to repeat the washing of the urethral lumen. A flexible urethral catheter should not be pushed if it finds resistance as it will bend, damaging it and hurting the urethral mucosa. Figure 10. Anatomical scheme of the urethra in cats. Observe the traction maneuvers of the penis in a caudo-dorsal direction that allows the alignment of the urethra, facilitating insertion of the urethral catheter. Modified by Cooper E. Vet Team Brief (2017). Video 4. Placement a flexible urethral catheter of polytetrafluoroethylene (Teflon). Note the position of the penis that allows alignment of the urethra and facilitates catheter advancement. Video 5. Placement a flexible polyethylene urethral catheter with barium and stylet. Video 3. Release of UO with olive-tip catheter in a cat with a urethral plug. In our experience, with this technique the release of a UO and placement of the urethral catheter is easy and without complications, mainly in patients who have not had any type of manipulation of the urethra beforehand. In some animals it is possible to find a rupture of the urethra or urinary bladder associated with maneuvers performed abruptly or incorrectly; so, if there is a suspicion of rupture of the urinary tract it is recommended to perform a retrograde urethrocystography with a contrast agent (17). Once the flexible urethral catheter is placed, it should be attached to the skin of the prepuce by four simple stitches of Nylon 2–0 or 3–0 and connected to a collection system (Figure 11). It is important to place the collection bag below the level the patient to allow urine to escape by gravity and prevent retrograde flow; the placement of an Elizabethan necklace is necessary to prevent the patient from damaging the collection or urethral catheter (2) (Figure 12). Once the obstruction is resolved, an X-ray study is recommended, as well as an ultrasound of the abdomen, to assess the presence of uroliths and to confirm the correct placement of the catheter (6). In animals with severe hematuria, the urinary bladder can be gently washed with saline, avoiding distending the bladder (10 mL per wash), to remove the greatest amount of cellular detritus and crystals (18). Washes should be repeated until the liquid is relatively clear. It is recommended that these washes should only be performed just after the urethral catheter has been placed; intermittent bladder washes on subsequent days is not recommended, as they do not reduce significantly the 6 REMEVET
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