Fluid Volume Imbalances (Grade A)

Summary:

Fluid volume imbalances refer to the condition where the body’s fluid intake is insufficient to meet its fluid needs. There are three types of dehydration: isotonic, hypertonic, and hypotonic. Isotonic is the most common type and is caused by plasma volume loss. Hypertonic dehydration occurs when water loss is greater than electrolyte loss, while hypotonic dehydration is due to the excess loss of Na+ and K+ from the ECF. Fluid volume excess, also known as overhydration/fluid overload, occurs when there is an excess of body fluids due to FVE in the vascular space or dilution of specific electrolytes and blood components. There are three types of fluid volume excess: isotonic, hypertonic, and hypotonic. Drug therapy, fluid restrictions, and monitoring I&O and lab values are some of the treatment options for fluid volume imbalances. Edema, ascites, and third space fluid accumulation are also discussed.

Excerpt:

FLUID VOLUME IMBALANCES

Dehydration, AKA Fluid Volume Deficit- The body’s fluid intake is not sufficient enough to meet the body’s fluid needs, resulting in a fluid volume deficit (FVD). Dehydration- refers to the loss of water without corresponding sodium loss.

3 types:
1. Isotonic- water and electrolytes are lost
2. Hypertonic- water loss is greater than electrolytes
3. Hypotonic- electrolyte loss is greater than water

ALWAYS GO TOWARDS MORE SOLUTES!
● Serum osmolality– think of chocolate syrup example
● Osmolarity-air-outside of the body
● Osmolality increases as water levels decrease, decreases as water levels increase

1. Isotonic
○ Most common type of FVD and caused by plasma volume loss.
○ ECF is lost from plasma and interstitial fluid spaces.
○ Serum osmolality remains normal.
○ No shift of fluid takes place, so ICF remains normal.
○ May lead to hypovolemia, which may decrease tissue perfusion. (isn’t enough plasma or RBCs)
○ Causes: hemorrhage, diarrhea, vomiting, diuretic therapy, GI suction, ostomies, severe wounds, abscesses, fistulas, burns, long-term NPO status, and frequent enemas. (fluid volume deficit)