Page 2382 - Cote clinical veterinary advisor dogs and cats 4th

Urethral Obstruction (Feline): Medical Management 1177

• Inform owners of the possibility of urinary Excessive manipulation or compression • When indicated, 3- or 5-Fr, flexible feeding
bladder rupture and guarded short-term of a devitalized, overdistended bladder wall tubes composed of material that minimizes
VetBooks.ir Possible Complications and painful, inadequately anesthetized patient • To minimize urethral trauma, avoid open-end
foreign body inflammatory response are
prognosis with or without therapy.
or excessive abdominal compression by a
preferred.
may promote rupture.
Common Errors to Avoid
catheters with sharp stylets.
• Cats with urethral obstruction and cardiovas- ○ Advantages of decompressive cystocentesis • Indications
Obtaining urine sample for analysis and
■
cular collapse rarely show overt signs referable culture ○ Inadequate/poor urine stream after
to the urinary system at the time of presenta- ■ Temporarily halting the adverse meta- urethral flushing
tion. Assessment of urinary bladder size (i.e., bolic effects of obstruction ■ Urethral spasm/swelling (≈1-3 days)
palpation or medical imaging) is essential ■ Reducing intraluminal bladder pressure ■ Excessive urinary precipitates (≈1-2
to avoid overlooking urethral obstruction to facilitate retropulsion days)
as the primary cause for cardiovascular or ■ Reducing pain associated with bladder ○ Assist correction of postrenal azotemia
respiratory distress. overdistention (≈1-2 days).
• Survey radiography is essential to verify, ○ Disadvantages of decompressive ○ Promote recovery of detrusor contractility
localize, and search for the underlying cause cystocentesis (≈1-5 days). Procedures and Techniques
of obstruction; radiographs should be per- ■ Potential extravasation of urine into ○ Promote repair of urothelial urethral tear
formed early in the diagnostic process before peritoneal cavity (≈3-10 days).
initiation of therapy. Non-obstructed dysuric ■ Bladder wall trauma • Care and management
cats usually have small urinary bladders. • Flushing plug contents out the external ○ Place as atraumatically and cleanly as
• Unsuccessful bladder expression is an unreli- urethral orifice possible.
able and sometimes unsafe (i.e., bladder ○ Attach open-ended catheter, IV extension ○ Maintain a closed collection system.
rupture) method of confirming urethral tubing, and large (35-mL) fluid-filled ○ Remove indwelling catheters as soon as
obstruction. syringe in that order. Displace air in the possible.
• Unsuccessful transurethral insertion of tubing by filling tubing and catheter with ○ If urine is initially sterile, avoid antimi-
urinary catheters is an unreliable and some- fluid from the syringe before insertion in crobial therapy until catheter is removed.
times unsafe (i.e., urethral tear, rupture, and the urethra. ○ If urine is initially infected, treat the
subsequent stricture) method of confirming ○ Insert tip of catheter into distal urethral infection (p. 232).
and localizing urethral obstruction. opening. ○ Treat potentially life-threatening infections.
• Caustic, strongly acidic flushing solutions ○ Flush a large quantity of sterile isotonic ○ Do not give the cat corticosteroids.
are contraindicated. solution into the urethral lumen, allowing • Nutritional therapy to dissolve struvite
it to reflux out the external urethral orifice. crystals, urethral plugs, or small struvite
Procedure The goal is to break up a urethral plug, uroliths (p. 1016)
• Sedate or anesthetize the patient. Consider similar to massaging the urethra. • Analgesia (1-2 days). Nonsteroidal antiinflam-
epidural anesthesia to locally control pain ○ Subsequent application of steady but matory drugs (NSAIDs) are contraindicated
and thereby minimize the quantity and risk gentle digital pressure to the bladder wall in cats with compromised renal function or
of general anesthetics. may result in expulsion of a urethral plug. dehydration.
• To fragment urethral plugs, gently massage ○ This method is unlikely to flush uroliths • Prevent negative fluid balance associated with
the distal urethra and cautiously compress the back into the urinary bladder. postobstructive diuresis by giving parenteral
urinary bladder with the goal of promoting • Retrograde urethral flushing (to propel fluids.
expulsion of plugs. This is easy to perform intraluminal contents into urinary bladder) • The following drugs are commonly adminis-
but not commonly effective. ○ Attach open-ended catheter, IV extension tered to cats without proven efficacy, safety,
• Decompressive cystocentesis tubing, and fluid-filled syringe (3-12 mL) or physiologic justification: urethral smooth-
○ Attach a 1 2 -inch, 22-gauge needle, in that order. Displace air in the tubing muscle relaxants (e.g., phenoxybenzamine,
1
IV extension tubing, and a 3-way stop- by filling tubing and catheter with fluid prazosin), urethral antispasmodics (e.g.,
cock. Then use a large-volume syringe from the syringe before insertion in the propantheline, oxybutynin), parasympatho-
(20-35 mL) to remove urine from bladder, urethra. mimetics (e.g., bethanechol), and skeletal
inserting the needle at the center of the ○ Insert tip of catheter into distal urethral muscle relaxants (e.g., diazepam, dantrolene).
bladder with the needle directed obliquely opening. If used at all, should be closely monitored.
(caudodorsally). ○ With a moistened gauze sponge, occlude
○ By using the IV extension tubing and the distal urethra around the catheter.
3-way stopcock between the needle and ○ Pull the penile urethra caudally to extend
syringe, the urinary bladder will not have it parallel to the vertebral column.
to be repunctured to empty a syringe full ○ Flush fluid vigorously by emptying syringe.
of urine. ○ Repeat urethral flushing if needed while
○ Excessive digital pressure should not be also remembering to repeat decompressive
applied to the bladder wall while the cystocentesis if bladder lumen becomes
needle is in the lumen to prevent urine distended with flushing solution.
from being forced around the needle into ○ The greatest pressure to retrograde hydro-
the peritoneal cavity. propulse is achieved with the smallest
○ Attempting complete evacuation of the syringe.
bladder lumen is undesirable because • In some cases, radiographs are indicated to
the sharp point of the needle may damage verify return of uroliths into urinary bladder
the bladder wall. The authors recommend or assess catheter placement.
that 5-15 mL of urine remain in the URETHRAL OBSTRUCTION (FELINE): MEDICAL
bladder. Postprocedure MANAGEMENT Assembled catheter, IV extension
○ Properly performed cystocentesis should Indwelling transurethral catheters: tubing, and syringe to facilitate removing obstruction
not contribute to bladder rupture. • Not always indicated in the urethra of cats.

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