Welcome to the Disease Du Jour podcast on the topic of Fluid Therapy in Horses with Drs. Kira Epstein and Naomi Crabtree of the University of Georgia College of Veterinary Medicine. Epstein was invited to write a review of fluid therapy in horses for Frontiers. She recruited Crabtree to assist in the paper.
Their goal with this paper was to highlight the controversies commonly found in using fluid therapy in equine practice, said Epstein.
Brought to you by Merck Animal Health
Epstein, DVM, DACVS (large animal), DACECC, is a professor in large animal surgery and emergency critical care and the interim department chair of the Department of Large Animal Medicine and Large Animal Emergency and Critical Care Service at the Veterinary Teaching Hospital at the University of Georgia.
Crabtree, DVM, MS, DACVS (large animal), DACECC, is a clinical assistant professor of large animal surgery and emergency critical care at the University of Georgia College of Veterinary Medicine.
Epstein said the challenges for the use of fluid therapy in horses is that there is not a lot of research, which is why she focused on a review. That allowed her to give more information and draw on other species, including humans.
“Relying on expert opinion is not the best way to practice,” she said. “I wanted to bring together information to [help us] parallel to human and other species in fluid therapy. I waned us to treat fluids like a drug … type, how to use, how long to use.”
Crabtree said there are several ways to get fluids into horses. IV is the most appropriate for large volume use. Nasogastric tube is another way to directly put fluids into the GI tract. Giving fluids via rectum is safe and offers systemic hydration as well as increases fecal water content.
Crabtree said as a student she was taught to use fluids to correct dehydration, maintain fluid levels and replace ongoing fluid losses. “What I missed was that I don’t need to do any or all [fluid replacement via IV,” said Crabtree. “Alternative routes might be easier in the field, safer and cheaper for the client.”
Epstein noted a quote she learned—”A horse’s most frequent cause of death is lack of dough.”
In the second part of the Summary of the paper, Epstein also warned against fluid overload while stating that “aggressive” treatment is about twice maintenance levels—no more. “And fluid is effective at lower rates,” she added.
Epstein talked about the third part of the Summary in the paper. One issue was the attempt to use non-sterile or compounded fluids for horses. Because of federal issues, Epstein recommends only using legitimate fluid options rather than compounded or homemade fluids.
But, said Epstein, “It is still your license and your choice to use.”
The fourth part of the Summery talked about types of fluids. “We fooled ourselves using the term ‘normal’ saline, said Crabtree. She said it is not a balance of sodium and chloride and is missing other things. “You need to figure out what type of fluid you are trying to replace,” she added.
Epstein said small animal veterinarians are no longer using the term “normal” when talking about saline. “This highlights the fact that these fluids are drugs,” she said.
The fifth and sixth parts of the Summary deal with colloids, which she said has a lower interest factor among veterinarians. Epstein said based on human studies, there is risk without a lot of positives.
Epstein said the summary “take-home” from the review article is that it highlights what we don’t know and that we need more research on fluid therapy in horses.
Crabtree said she “echoes that. The safety or lack thereof in maintaining a catheter and possibly deadly complications” need to be considered.
The two practitioners and researchers then talked in-depth about using fluids in colic cases. One point they made was that trying to “hang” IV fluids on a horse being transported in a trailer to a hospital is difficult to achieve. They caution that the severe negative side effects can be a worst-case scenario, and in best-case scenarios it can just waste the owner’s money.
Current Concepts in Fluid Therapy Publication 2021
Abstract: “Despite the frequent inclusion of fluid therapy in the treatment of many conditions in horses, there are limited studies available to provide evidenced-based, species-specific recommendations. Thus, equine fluid therapy is based on the application of physiology and extrapolation from evidence in other veterinary species and human medicine. The physiologic principles that underlie the use of fluids in medicine are, at first glance, straightforward and simple to understand. However, in the past 20 years, multiple studies in human medicine have shown that creating recommendations based on theory in combination with experimental and/or small clinical studies does not consistently result in best practice. As a result, there are ongoing controversies in human medicine over fluid types, volumes, and routes of administration. For example, the use of 0.9% NaCl as the replacement fluid of choice is being questioned, and the theoretical benefits of colloids have not translated to clinical cases and negative effects are greater than predicted. In this review, the current body of equine research in fluid therapy will be reviewed, connections to the controversies in human medicine and other veterinary species will be explored and, where appropriate, recommendations for fluid therapy in the adult horse will be made based on the available evidence. This review is focused on the decisions surrounding developing a fluid plan involving crystalloids, synthetic colloids, and plasma.”