Careful consideration of preoperative, intraoperative, and postoperative management techniques will assist in preventing
complications related to anesthesia and surgery in patients with urinary tract surgical disease. Hospital acquired renal
insufficiency is common in humans, seemingly less so in animals but caution is advised. Hypotension of any cause is a potential
predisposing cause to renal failure.
Potential Causes of Hypotension
Hypoperfusion may also potentiate the deleterious effects of other nephrotoxins such as aminoglycoside antibiotics, anesthetic
agents, and NSAID's.
1. Hypovolemia and electrolyte imbalance corrected PRIOR to definitive surgery. Maintenance of a normovolemic state
and NORMAL urine production (0.5-1.0 ml/kg/hr) during the anesthetic episode is a goal.
2. Administration of crystalloid fluids (LR or other balanced electrolyte solution) at rates of 10 ml/kg/hour in the
normal healthy patient is routine, HIGHER rates if there is preexisting disease.
3. Measuring urine production may be advantageous and requires nothing more than an indwelling u-cath and a closed system.
AIDS if patient is oliguric (choose one or more)
1. Furoseamide 2-4 mg/kg bolus
2. Dopamine 2-5 ug/kg/minute infusion, dose is critical, more is NOT better, causes vasoconstriction
3. Mannitol 0.5 gram/kg bolus
Anemia may be associated with chronic renal failure (CRF) or secondary to specific surgical procedures such as Urethrostomy
which may result in excessive bleeding. Consider Packed cells or whole blood for those animals needing surgery who have a
PCV below 25.
Surgical Exposure/Anatomy- Depends Upon Which Portion Of The Urinary Tract One Wants To Expose;
-Cranial ventral midline from xiphoid to midway between umbilicus and pubis for upper urinary tract (kidney)
-Umbilicus to pubis for lower urinary tract
-Pubic osteotomy or ostectomy MAY be necessary to expose pelvic urethra
-Episiotomy for exposure of the urethral papilla in the female
-Balfour retractors for exposure of the abdomen extremely valuable
Use of the duodenum & mesoduodenum on the right side and the colon and mesocolon on the left side as anatomic retractors will
help you in exposing the kidney/ureter on the respective side.
Renal Surgical Disease
The kidneys lie in the sublumbar region and are retroperitoneal. The right kidney is more cranial than the left and is fixed
to the liver by the hepatorenal ligament. Recall that the kidneys receive large volumes of total cardiac output by the renal
arteries which are direct extensions of the aorta. Reportedly, about 10-20 % of dogs have more than one renal artery on the
left side. The arteries are rostral and dorsal to the respective renal veins which are easily visualized. The right kidney
is closely associated with the caudal vena cava and disease (neoplasia) of the right kidney may involve the vena cava. A
GLOBAL picture of renal function is obtained by blood work and BUN/Creatinine assessment, urinalysis, and urine culture.
***Functional status of an individual kidney can be difficult to determine. Excretory urography is a qualitative study of
kidney filtration but is not a quantitative study. If no contrast is excreted by a kidney no function is present but if contrast
is excreted we can't determine how much function is present. 2-3 mm of functional cortex is enough to consider salvage of
a kidney. Renal scintigraphy is the only non-invasive technique for measuring glomerular filtration but is not widely available.