Renal Replacement Therapy: A Future Option for Horses?

When a person or small animal’s kidneys are injured, stressed, or fail, renal replacement therapy can create a life-saving bridge until kidney function recovers (or, in some human cases, a donor organ is secured). In horses similar treatment generally isn’t an option, and renal failure is devastating.

To investigate the possibility of developing a viable solution for horses suffering kidney injury or disease, David M. Wong, DVM, MS, Dipl. ACVIM, ACVECC, of Iowa State University College of Veterinary Medicine Lloyd Veterinary Medical Center, in Ames, decided to investigate the use of renal replacement therapy in equids.

He presented the results of his study, “Renal Replacement Therapy in the Horse: A Viable Clinical Option?” at the American College of Veterinary Internal Medicine Forum held June 12-15 in Seattle, Wash.

Renal Replacement, the Cliff Notes Version

Kidneys are organs of the urinary system that provide essential regulation of electrolytes, blood-pressure (salt and water balance), and acid-base balance as they filter waste from the blood and expel it through the urine.

Wong explained that renal replacement therapy includes artificial techniques that mimic or augment kidney function, typically in the clinical setting of acute renal failure (ARF). The goals of treatment include:

  • Maintaining fluid, electrolyte, acid-base, and solute balance;
  • Preventing further kidney insult;
  • Promoting healing and renal recovery; and
  • Permitting supportive measures (i.e., nutrition) to proceed without limitation.

These techniques include modalities such as intermittent hemodialysis, peritoneal dialysis, and continuous renal replacement therapy (CRRT).

In horses, renal replacement could potentially help in removing toxins, inflammatory cytokines and drugs (in cases of over- or accidental dosing) from the horse's system, and when the horse experiences tying up (rhabdomyolysis), sepsis (infection), and endotoxemia, Wong said.

Study Results

Wong’s study included five healthy adult horses undergoing CRRT for six hours each. The sedated animals had dialysis catheters inserted into their left jugular veins, while three other catheters were placed to monitor arterial blood pressure, administer continuous sedation, and allow blood collection.

The team, which included an experienced dialysis nurse, connected the horses to a commercial CRRT machine for dialysis treatment and monitored vital signs, including heart rate, respiratory rate, body temperature, blood pressure, and heart rhythm.

Wong described complications associated with treatment as minimal jugular and facial artery hematoma (bruising) at catheter sites, heart arrhythmias, and hypothermia.

Future Application

Veterinarians rarely use renal replacement therapy in equine veterinary and critical care, mostly because its labor-intensive nature and that CRRT machines are not designed for 1,200-pound animals, Wong said.

“The future of CRRT in equine medicine is unknown, but might provide an adjunct therapy to improve outcome to equine patients with ARF,” he concluded.

Disclaimer: Seek the advice of a qualified veterinarian before proceeding with any diagnosis, treatment, or therapy.