Fluid Therapy in Pets

Many people outside the veterinary world are not aware that fluid therapy is actually one of the most common therapies provided in small animal medicine.  Patients can be given fluids by several different methods and for many different reasons.  The number of available fluids is also growing.  Understanding the basics of fluid therapy may help you feel more at ease if it is ever ordered for your pet in a veterinary setting. 

Fluid therapy may be administered for many reasons, including:  correction of dehydration, expansion and support of intravascular volume, correction of electrolyte disturbances, and encouragement of appropriate redistribution of fluids that may be in the wrong compartment in the body.  Some more common examples (and less scientific sounding) are if your pet is severely dehydrated (perhaps from vomiting or diarrhea), is in shock due to the loss of blood or fluids from an accident, has consumed something it shouldn’t (poison, antifreeze, food it shouldn’t have, etc.) or is diagnosed with a disease that affects the fluids in its body.

The first step to determine if a patient needs fluid therapy is a full physical exam.  Consideration of fluid losses is an important part in determining a fluid therapy plan.  These losses must be factored in when deciding the type, amount, and route of fluid therapy. 

Fluid administration can be accomplished in several different ways.  Oral, subcutaneous, intravenous, and intraosseous routes can be used depending on the species receiving the fluid and why it is needed. 

The oral route is by far the simplest and can be as easy as offering the patient a bowl of water.  This is typically used in milder cases of dehydration.  The subcutaneous route is very common, but is not appropriate for life-threatening conditions.  Many owners can be trained to provide this therapy at home.  The intravenous route is also very common and a more appropriate method in emergency situations.  When an IV catheter is placed into a vein, this allows for restoration of intravascular volume, dehydration correction, as well as the administration of IV medications.  The intraosseous method (catheter placement in the medullary cavity of a bone) is used when IV access is difficult or impossible.  This route is also very useful in tiny patients such as neonates and pocket pets like hamsters or gerbils.  This method is not as common because fluid cannot be provided at a rate equivalent to that of IV access and the needles are not designed for long-term use.

Monitoring fluid therapy is very important.  This is the reason that in most cases many veterinary staff want to keep the patient in their hospital while administering fluids.  Fluid overload can be a major complication that is best avoided by diligent monitoring. 

There are many different fluids available for fluid therapy in pets and they each have their “time and place.”  Determining which fluid an animal needs depends on the species of the animal, how the patient presents to the veterinary staff, and the diagnosis given.  The amount of time fluid therapy is administered also varies greatly between patients depending on the situation of each. 

In most cases the administration of fluids is simple with the proper skills.  The use of anesthetic is rarely used for any route of fluid therapy unless the safety of the administrator or patient is at risk.  

Understanding the need for fluid therapy and the methods used is important for pet owners to know in case you find yourself suddenly in this situation.  As always, the more you know, the better!