Question

A dehydrated patient needs to be rehydrated with an IV of Ringer's solution. At the start of their rehydration therapy, right when the IV is first connected, what is the tonicity of the cells of their body compared to the Ringer's solution? Once the patient is fully rehydrated, and the IV is stopped, what is the tonicity of the cells in the patient's body compared to the Ringer's solution?

Answer 1

So what type of IV solutions are hypertonic?  These are the common ones:

10% Dextrose in Water3% Saline5% Dextrose in 0.45% Saline5% Dextrose in 0.9% Saline

Notice that three of the solutions contain Dextrose, which is a sugar.  The dextrose is included as a way of providing extra calories to the patient.  In fact, even though these dextrose solutions are hypertonic, once the dextrose is absorbed by the body then only pure water or saline is left in the blood vessels.  These three solutions are primarily used for the purpose of providing the patient with extra calories.

3% saline is typically used to treat severe cases of hyponatremia (low sodium).