The IV bag that was available in class read .45% NaCl. What is the osmolality of this bag? What is the significance of this value? When would you use an IV bag of this concentration?

Each 100 mL of 0.45% Sodium Chloride Injection, USP contains 450 mg sodium chloride in water for injection.

Electrolytes per 1000 mL: sodium (Na+) 77 mEq; chloride (Cl-) 77 mEq.

The osmolality is 154 mOsmol/L

This solution is hypotonic with a pH of 5.6.

Normal NaCl solution for IV is 0.90%. This is isotonic.

It is used for hypotonic hydration and to replace sodium and chloride. It would be needed if a person has hyperosmolar diabetes.

Hypotonic saline fluids such as 0.45% sodium chloride solution, which expand the intracellular compartment, are indicated for hypertonic dehydration, gastric fluid loss, and cellular dehydration from excessive diuresis.

But there can be problems if too much is mixed with blood cells during transfusion, the cells will pull water into them and rupture.

When using this, be aware that there will be more water outside of the cell than inside of it.