Veterinarians at Tufts Raise Awareness of Intravenous Fluid Therapy Complications

When critically ill animals arrive in veterinary emergency rooms, one of the first steps to recovery is to put them on intravenous fluids—often a salty mixture of electrolytes and water meant to counter dehydration and restore adequate blood flow. This decision saves lives, but after a few hours to days, if not closely monitored the same fluids may start to do more harm than good, say Tufts experts, potentially causing organs to swell or malfunction. Weight gain of more than 10 percent from overuse of fluids can be especially dangerous for small animals, reducing their chances of survival.

“People aren’t talking about this,” says Alexandra Pfaff, a clinical assistant professor at Cummings School of Veterinary Medicine at Tufts University. “Research on fluid overload in pets is scarce and the concept of fluid stewardship has not been described. Implementation of such programs at more veterinary institutions would improve care in an area that affects patients and clinicians every day.”

Inspired by a similar movement in human medicine, Pfaff has spent years helping veterinary clinicians rethink their approach to fluid administration. She founded the Tufts Fluid Stewardship Team in 2021, bringing together experts from nephrology, anesthesia, nutrition, and other subspecialties to develop guidelines to improve fluid management in small animal medical practices.

“Fluids are actually some of the most difficult medications to prescribe, with different concentrations, types, and rates of administration that need to be considered,” says Cummings School Clinical Assistant Professor Emmanuelle Butty, Pfaff’s counterpart on the fluid stewardship team who specializes in kidneys and dialysis. “We’re developing recommendations based on what we currently know, but we’re at the very beginning.”

“Yet, fluids are frequently not considered medications and therefore formulation and monitoring of fluid prescriptions doesn’t follow the same thought process as the prescription of other drugs, such as antibiotics,” Pfaff says. “We want to ensure that benefits are maximized, and adverse effects are minimized, which enhances patient outcomes and has cost-reducing effects.”

Finding the Right Dose

When introducing the idea of fluid stewardship, Pfaff likes to quote Swiss physician Paracelsus (1493–1541), who is credited with saying: “All things are poison, and nothing is without poison; only the dose makes a thing not a poison.”

The fluid team’s goal is to move veterinary medicine to a place where fluid therapies are individualized, prescribed like drugs, and reassessed daily. Research on critically ill human patients identifies four phases where a person’s fluid needs change. In the first minutes to hour of emergency care, the focus is resuscitation, increasing fluid balance, which is optimized over the course of the day depending on the patient’s responsiveness. Fluid intake should equal fluid loss by days 2–3 as the patient stabilizes. The goal is to achieve a negative fluid balance by days 3–7.

“Another area of discussion is the amount of fluid administered as drug diluents or flushes to keep veins accessible,” says Pfaff. “In people, between 25–61% of total daily fluids in intensive care patients consist of ‘hidden fluids’ that are typically not accounted for in fluid therapy plans and have been correlated with fluid overload and increased length of hospitalization.”

“In a healthy animal, you probably have a lot of wiggle room where fluids are not going to cause harm, but very sick patients are going to be less tolerant of any type of error,” says Butty. “Kidneys need time to work, so if we overdo it, they are going to overload and work less effectively. We’ve been able to remove these excess fluids with dialysis and see patients immediately feel better.”

An effective fluid stewardship team would combine multiple services to assess and reassess patients’ fluid levels across the different stages of their care. For a very sick animal, recommendations could change hour-by-hour. How various procedures and prescriptions affect a patient’s fluid levels would be clear from the team’s guidelines and supported by communication between the attending physicians.

Filling the Gaps

When Pfaff started her fluid stewardship work, she didn’t expect it to generate this much interest. While human medicine is tackling the exact same issues, it’s had at least a 10-year head start and more financial support to run large studies.

“There’s general discomfort among clinicians about how to prescribe fluids, going from a time when everyone was a lot more liberal about them to a trend of sometimes being too restrictive, which is just as detrimental,” Pfaff says. “The work we’re doing is helping get people more comfortable, but that’s going to take time.”

Based on best practices in human medicine, Pfaff recommends animal hospitals start to implement fluid stewardship programs by auditing patient records and logs to identify areas of concern. Next, they can conduct surveys within the hospital to assess knowledge gaps around fluid prescription and composition. Finally, they can create educational materials based on the learnings.

The Tufts Fluid Stewardship Team’s focus is now on writing research papers, trying to fill gaps in the veterinary literature with the goal of formulating evidence-based guidelines in the future. They have already identified a couple of areas where they can get to work developing reliable tools to better assess a patient’s fluid status.

“Our goal is to create studies that highlight the potential complications of fluid misuse and raise awareness of the issue so we can do the best job possible for our next patient,” says Butty. “This is why I stayed in academia, not just to practice what I learned, but to advance veterinary medicine using a team-based approach with our amazing colleagues.”

“There are so many unanswered questions, but we’re getting the message out there,” says Pfaff. “There are times when I feel like it takes a long time to make progress, but then I’m contacted by someone who heard about what we’re doing, and I’m reminded, baby steps.”