Fluid Volume:Nursing Assessment Findings



  • Dehydration occurs when the fluid intake of the body is not sufficient to meet the fluid needs of the body.
  • The goal of treatment is to restore fluid volume, replace electrolytes as needed, and eliminate the cause of the fluid volume deficit.

Fluid Volume 1

Fluid volume 2

Types of fluid volume deficits

Isotonic dehydration

  • Water and dissolved electrolytes are lost in equal proportions.
  • Known as hypovolemia, isotonic dehydration is the most common type of dehydration.
  • Isotonic dehydration results in decreased circulating blood volume and inadequate tissue perfusion.

Hypertonic dehydration

  • Water loss exceeds electrolyte loss.
  • The clinical problems that occur result from alterations in the concentrations of specific plasma electrolytes.
  • Fluid moves fromthe intracellular compartment into the plasma and interstitial fluid spaces, causing cellular dehydration and shrinkage.
  • Hypotonic dehydration
  • Electrolyte loss exceeds water loss.
  • The clinical problems that occur result from fluid shifts between compartments, causing a decrease in plasma volume.
  • Fluid moves from the plasma and interstitial fluid spaces into the cells, causing a plasma volume deficit and causing the cells to swell.


Causes of fluid volume deficits

Isotonic dehydration

  • Inadequate intake of fluids and solutes
  • Fluid shifts between compartments
  • Excessive losses of isotonic body fluids

Hypertonic dehydration—conditions that increase

  • fluid loss, such as excessive perspiration, hyperventilation, ketoacidosis, prolonged fevers, diarrhea, early-stage renal failure, and diabetes insipidus

Hypotonic dehydration

  • Chronic illness
  • Excessive fluid replacement (hypotonic)
  • Renal failure
  • Chronic malnutrition


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