AAHA and the American Association of Feline Practitioners recommend the use of fluid therapy during even minor procedures, but not all hospitals act on the recommendation - usually due to added costs.

In an attempt to more accurately gauge the importance of giving IV fluids for a wide range of surgical procedures, researchers from Penn Vet collaborated with experts from Abbott Laboratories and Colorado State University to monitor the blood flow of dogs undergoing spay surgeries.

In the study, recently published in the American Journal of Veterinary Research, researchers sought to find out whether administering IV fluid during a minor surgery would impact microcirculation in healthy animals. They also wanted to determine which level of fluid delivery produces optimal results, Penn Vet reported.

The researchers enrolled 49 healthy client-owned dogs and separated them into three groups: one receiving no fluid, one receiving 10 milliliters per kilogram weight per hour of lactated Ringer's solution, and one receiving 20 milliliters per kilogram weight per hour.

They then used a video microscope placed against the dogs' gums to monitor flow through blood vessels of various sizes both before the procedure and 30 and 60 minutes after the animals were anesthetized. 

The researchers analyzed the videos recorded during the study and reported that:

• There was no observable difference among the groups in the proportion of vessels with blood flow or the amount of flow within the vessels.
• They did not observe any differences among the groups in capillaries that are less than 20 micrometers in diameter.
• In blood vessels larger than 20 micrometers, researchers found that dogs receiving the greatest amount of fluids had greater densities of these blood vessels than dogs receiving no fluids. They also had greater densities of these larger vessels with blood flow compared to the control group, study authors reported.

"The larger vessels are the ones that are constricting and dilating to feed the microcirculation," said Deborah Silverstein, DVM, associate professor at Penn Vet's Department of Clinical Studies-Philadelphia. "And it appears that the animals that got the highest rate of fluids in this study - which may not be the optimal rate - are the ones that seemed to have the greatest recruitment of arterioles and venules."

The study authors concluded that the results of their study underscore the importance of giving IV fluids even during minor, elective surgical procedures for animals.

Read the full study at the American Journal of Veterinary Research.