Page 189 - Problem-Based Feline Medicine

11 – THE CAT STRAINING TO URINATE 181

● Consider cystocentesis for temporary relief of – Exteriorize the penis from the prepuce and
bladder distention. extend it caudally so as to straighten the natural
● Give dextrose saline solution IV (0.9% NaCl with curvature of the cat’s penis. Clean with warm
5% dextrose – add 100 ml of 50% dextrose per liter water.
of fluids) to rehydrate the patient over 4–6 hours – As aseptically as possible, fill a 3.5 French,
and reduce hyperkalemia, metabolic acidosis and open-ended urinary catheter (olive tip ure-
azotemia. thral catheters, Jorgensen Laboratories) with
● Cats in renal failure are frequently hypothermic and lubricating gel (xylocaine jelly at room tem-
should be warmed to normal body temperature. perature) and gently pass the catheter into the
urethra, until it comes in contact with the
Remove the obstruction. obstructing material, which is usually at the
● Immobilization. level of the bulbo-urethral gland where the
● Sedation during catheterization will help mini- urethra narrows and becomes the penile portion.
mize further urethral trauma and urethral or – Instill 0.25 ml of lubricating gel through the
bladder rupture. catheter into the urethra and remove the catheter.
● Urethral trauma from catheterization can lead to After 3 minutes, the jelly usually has lubricated
inflammation with edema of the periurethral tissue and broken up the obstructing mass, allowing it
and subsequent functional urethral obstruction. to be spontaneously extruded like toothpaste by
● Inappropriate force or the cat struggling during the high urethral pressure cranial to the obstruc-
catheterization may result in urethral or bladder tion. If the material re-obstructs, repeat the
rupture. procedure several times using 0.15 ml of gel,
● The degree of sedation required will depend on the until urine appears. This technique ensures that
cat’s clinical condition and temperament. all the obstructing material in the urethra has
● An opiate (pethidine (meperidine)) 1 mg/kg SC; been removed and little if any has been pushed
butorphanol (0.05–0.4 mg/kg IV, SC; buprenor- into the bladder. If spontaneous resolution of the
phine 0.005–0.01 mg/kg IV, SC) and acepromazine obstruction does not occur, apply gentle pres-
(0.02–0.05 mg/kg IV, SC) or an opiate and sure to the bladder. Great care should be exer-
diazepam (0.25 mg/kg SC, IV) can be used. cised when applying pressure to the urinary
● Premedicate with atropine sulfate (0.03 mg/kg) bladder, as it can lead to bladder rupture.
subcutaneously or intravenously combined in the – Retropulsion with a saline flush is commonly
same syringe as the opiate. Intravenous ultra used in practice, but is more likely to lead to re-
short-acting barbiturates (sodium thiamylal or obstruction, because obstruding material is
thiopentone (thiopental)), propofol, alfaxalone and pushed into the bladder.
inhalant anesthetics (isoflurane) can be used. – If local anesthetic agents are combined in the
Depressed cats can be masked down with isoflurane lubricating gel to anesthetize the urethral mucosa,
and oxygen. Beware of intubating the cat before it they should be used sparingly to avoid local
has reached a suitable plane of anesthesia, as intu- and systemic toxic effects that are more likely to
bation may cause reflex bradycardia or cardiac occur in the presence of damaged urothelium.
arrest. Spray the larynx with lignocaine (lidocaine) – Recatheterize with a long, soft, flexible Teflon
prior to attempting intubation. urinary catheter (3.5–4 French), secured in
● Succinylcholine is contra-indicated as it increases place with sutures, to empty the bladder com-
serum potassium levels. pletely.
● Catheterization of the bladder in cats with severe – Once the bladder has been catheterized, urine is
renal failure may be possible by using physical allowed to drip freely. Avoid removing urine by
restraint only. negative pressure (syringe) or by applying
● Catheterization. external pressure on the urinary bladder as this
– The method employed and the instrumentation can unnecessarily traumatize the bladder mucosa.
used to remove the obstruction must ensure that – If the urine is visibly clear: Instill 5–10 ml of
no further urethral or bladder trauma occurs. sodium acetate/acetic acid buffer solution