Filtering the future: Hemoperfusion brings new hope for septic horses

BRYAN-COLLEGE STATION, Texas — Sepsis, a condition in which the immune system spirals out of control in response to an infection, is one of the most life-threatening health concerns a horse can face.

Managing it requires medications, fluids, and other supportive care, which quickly add up to long hospital stays and overwhelmingly expensive bills. Even then, survival is far from guaranteed — only 30-40% of horses survive and those that do are often left with severe complications.

However, a new technology called hemoperfusion is offering hope for septic horses; it may be able to stop the condition from becoming life-threatening, while also lowering both the time and cost of treatment.

Dr. Kallie Hobbs, an assistant professor at the Texas A&M College of Veterinary Medicine & Biomedical Sciences who has been at the forefront of hemoperfusion research, shares how the technology works and the difference it could make for septic horses.

FILTERING OUT THE DANGER

Normally, when bacteria or other microorganisms invade a horse’s bloodstream, the immune system releases cytokines — inflammatory signals or messengers that help the body fight off infection.

“In a septic horse, however, there’s an overproduction of cytokines, a ‘cytokine storm,’ that overwhelms the immune system and prevents it from fighting the infection,” Hobbs said.

In cases of sepsis, hemoperfusion may help the immune system “reset” by physically removing those excess cytokines, restoring the body’s natural ability to fight infection.

“A hemoperfusion machine uses a cartridge filled with beads — called a column — to filter out the cytokines, very similar to a water filter,” Hobbs said. “A catheter draws blood from the horse, the blood passes through the hemoperfusion column for filtering, and then the cleaned blood is returned to the horse.

“Depending on what the problem is and the size of the animal, a session can be anywhere from four to 12 hours,” Hobbs said. “For the sepsis cases we’ve treated in horses, it’s always taken about four to six hours. And most horses just stand and eat hay while we run the treatment.”

GAME CHANGER IN CRITICAL CARE

Polymer-based hemoperfusion — which gained renewed interest during the COVID-19 pandemic — is still new in the veterinary world, but it has already shown encouraging results and may become a breakthrough for treating horses with sepsis. One of the most promising aspects is how fast horses improve after filtering.

“I’ve filtered blood in several horses with sepsis that have otherwise failed traditional treatment, and I have noted a rapid improvement in their clinical signs,” Hobbs said. “One patient, for example, was able to substantially decrease the medications they were on within 24 hours after we did the treatment.”

Beyond speed, this technology can also ease the financial and emotional toll of a sepsis diagnosis.

“It has the potential not just to save lives but to save time and costs as well,” Hobbs said. “Sepsis can lead to horses being in the hospital for a long time, and each day can cost several thousands of dollars to keep the patient stable. Reducing treatment time also reduces stress on the animal and allows veterinarians to help more patients.”

OTHER USES

While sepsis has been Hobbs’ primary focus, hemoperfusion has also proven useful in other emergencies, successfully treating toxicity cases such as rat bait ingestion and venomous snake bites — instances where dangerous substances can be physically removed from the blood.

“We know it pulls out Western Diamondback snake venom,” Hobbs said. “With continued research, we hope to figure out exactly what conditions respond best to hemoperfusion.”

Because hemoperfusion is still new in veterinary medicine, it’s not widely available — yet.

“Currently, Texas A&M is one of the only three teaching hospitals that can perform hemoperfusion on animals,” Hobbs said. “We have been publishing data showing not only that polymer-based hemoperfusion works but also how it works, which will hopefully expand its acceptance and availability as a treatment.”

For Hobbs, the goal is to see hemoperfusion become an established part of sepsis care.

“Right now, hemoperfusion is the last resort to save a horse that’s not responding to anything else,” Hobbs said. “My hope is that it will become a management strategy we can use early, instead of waiting until everything else has failed.”

Pasture Talk is a service of the College of Veterinary Medicine & Biomedical Sciences, Texas A&M University. Stories can be viewed on the web at vetmed.tamu.edu/news/tag/pasture-talk. Suggestions for future topics may be directed to vmbs-editor@tamu.edu.