Administer supplemental potassium. Potassium is often deficient in cats with renal failure because of the polyuria that has been occurring for weeks to months. Therefore, a vicious cycle of renal failure, potassium depletion, and worsening renal failure ensues. This cycle needs to be broken. Since intravenous potassium can cause fatal hyperkalemia, the use of oral potassium has definite advantages.
Metabolic acidosis is a frequent consequence of renal failure.
If acidosis is marked, add sodium bicarbonate to the intravenous fluids. And be sure to carefully monitor the patient. Reduce the serum phosphorus concentration. A phosphate binder is indicated when hyperphosphatemia occurs. Therapeutic renal failure diets are low in phosphorus and blunt the rise in or decrease the serum phosphorus concentration.