Hypodermoclysis

In medicine and veterinary medicine, hypodermoclysis is a method of injecting, subcutaneously, large volumes of fluids for treating dehydration and water-electrolyte imbalance. It was in use before intravenous infusion became practical.

It has largely been abandoned in human medicine, but retains a significant role in veterinary medicine. With humans, subcutaneous injection of large volumes tends to be uncomfortable and does not enter the circulation as quickly as does the intravenous or intraosseous route. For animals such as cats and dogs, however, their loose skin stretches easily to accommodate large fluid volumes.

While essentially the same equipment is used for intravenous infusion and hypodermoclysis, the technique of introducing a hypodermic needle (or catheter) under an animal's skin is far easier than into a vein. It can, therefore, be made available for home use; among its applications can be considerably increasing the comfortable life of a companion animal with chronic kidney disease.

Given that it can be performed by relatively untrained personnel, it is of potential benefit in mass casualty incidents or epidemics. Oral rehydration fluid, however, has largely done away with the need for injected fluids in many epidemics such as cholera.