Page 470 - WSAVA2017
P. 470

An Urban Experience
ultrasound is useful for detecting pyelectasia, calculi, mass lesions, and other intraabdominal abnormalities that may be related to azotemia. Occasionally a ureteral obstruction may require contrast pyelography to diagnose.
A classification scheme has been proposed for staging V in dogs. (Table 1; Thoen 2011)
Table 1: Proposed Veterinary Acute Kidney Injury (V) staging system for dogs
from vomiting, diarrhea, respiratory disease, polyuria, etc. need to be calculated and replaced. These fluids are estimated, or can be measured. Urine output can be monitored by a variety of ways: 1. a urinary catheter can be placed and attached to a closed collection system, 2. the urine can be collected during walks, 3. The urine can be quantified using a metabolic cage, 4. The bedding can be weighed (1g=1ml urine), and 5. weighing the animal. Fluid balance can be complicated in the AKI patient. Determination of fluid rates is best determined by closely monitoring and comparing fluid losses
with infusion volumes, and monitoring central venous pressure.
Pharmacological intervention may be necessary when uremia is present, infection is suspected or hypertension is present. H2-blockers reduce acid secretion and reflux as well as promote mucosal healing when gastritis or uremic ulcers are suspected. Pantoprazole (0.7 mg/
kg IV q 24h) is the preferred drug by the authors during hospitalization. Liquid sucralfate (0.5-1g PO q6-8hr)
may coat an area of uremic erosion once vomiting
is controlled When vomiting from stimulation of the chemoreceptor trigger zone in the brain is suspected, substance-p and serotonin inhibitors, such as maropitant (2-8 mg/kg PO; 1mg/kg SQ q 24h), and ondansetron (0.1-0.3 mg/kg SQ TID, or 0.5 mg IV load then 0.5 mg/ kg/hr CRI) or dolasetron (0.5 mg/kg IV, SQ q 24h), may also be helpful. Placement of a nasogastric tube can aid in decompressing the stomach and reducing nausea, as well as provide a means for administering medications and nutritional support. Early feeding using liquid diets can improve gastrointestinal function and recovery rate. When it is periodically suctioned, the volume can be used in calculation for ongoing fluid losses.
Phosphate binders (aluminum hydroxide, aluminum carbonate, calcium acetate) may decrease phosphate absorption when the patient has hyperphosphatemia. Acid base disorders generally correct with adequate fluid resuscitation and reestablishing urine output.
For cases suspected to have a urinary tract infection, broad spectrum antibiotics covering for many aerobic infections is administered intravenously. Ampicillin (22 mg/kg IV q6hr), ampicillin-sulbactam (22 mg/kg IV q6hr), and cefazolin (22 mg/kg IV q 8h) are good choices. It is preferred that a urine sample for culture is obtained prior to starting antibiotics.
In the cardiovascularly stable patient, diltiazem (0.3–0.5 mg/kg slow push (10 min) followed by 3–5 μg/kg/min constant rate infusion (CRI) X 48 to 96 hours) can also lower the creatinine more effectively that diuresis alone in dogs with leptospirosis. A lowering of ~15 mmHg systolic blood pressure is expected, and heart rate and blood pressure must be frequently monitored.
V stage
Stage 0
Stage 1
Creatinine increase of 26.5 mmol/L (0.3 mg/dL) from baseline
Creatinine increase <150% from baseline Creatinine increase of 150–199% from baseline
Stage 2
Stage 3
An absolute creatinine value >354 mmol/L (4.0 mg/dL) PREVENTION
Creatinine increase of 200–299% from baseline Creatinine increase of ≥300% from baseline
All critically ill animals are at risk for sustaining AKI. Maintaining hydration and renal perfusion will reduce
risk of renal toxicity, and all critically ill patients should have renal parameters monitored daily (Creatinine, UO, electrolytes). When potentially nephrotoxic agents are used in the critical dog, daily comparison of urine GGT to creatinine ratio to baseline values may uncover early renal toxicity.
Circulatory abnormalities (hypotension, poor perfusion, arrhythmias) caused by hypovolemia and hyperkalemia must be rapidly corrected. The mainstay to treatment of AKI is to reperfuse the kidneys and promote excretion
of toxic substances. Because AKI and hypovolemia generally cause an acidosis, a balanced buffered isotonic crystalloid is chosen for resuscitation and rehydration. Small volume resuscitation techniques to normal perfusion endpoints are used until urine output is better characterized. Once perfusion has been restored, tissue hydration deficits are calculated and replaced over 4-10 hours. The calculated volume to replace is based on hydration status and laboratory parameters.
% dehydration × body weight (kg) = L of fluid required for replacement
In addition to the volume being administered for rehydration, sensible and insensible losses need to be accounted for (1-2 ml/kg/hr). Finally, ongoing losses

   468   469   470   471   472