Fluid Therapy | Solutions & Their Use

Crystalloids: water-based solutions having small particles which are normally osmotically active in body fluids & can pass through the capillary membrane.

Following crystalloid solutions are generally used in veterinary practice and animal fluid therapy:

A. Isotonic solutions

  1. Balanced solutions
    • Polyionic solutions (Ringer’s solutions)
  2. Unbalanced solutions
    • 0.9% NaCl solution
    • 1.3% NaHCO3 solution
    • 5% dextrose solution

Colloids: contains large particles which cannot pass through the capillary membrane & so do not leave the vessel but attract & hold water in the vascular spaces thus expanding the plasma volume.

Colloidal solutions are divided into natural and synthetic compounds.

A. Natural colloid solutions
1. Whole blood
2. Plasma
B. Synthetic colloid solutions
1. Hetastarch
2. Dextrans
3. Modified gelatin solutions

  1. Dextrose Solution

It is available in concentrations of 5 %, 10%, 25%, and 50%.


  1. To prevent tissue catabolism
  2. To prevent ketosis
  3. To counter dehydration
  4. To deplete liver glycogen

5% dextrose in water is mainly used as maintenance fluid and as a source of energy & more as a source of free water.
Oxidation of 1g of dextrose yields 0.6ml of water that adds to total body volume.

Hypertonic dextrose solution (10%, 25%, 50% dextrose sol.) are used for treatment of hypoglycemia & ketosis.
Used carefully as may draw water from the tissue into the plasma space & water may be lost faster than glucose can be metabolized.

2. Sodium Chloride Solution


  1. Vomiting
  2. Profusse sweating
  3. Alkalosis
  4. Gastroenteritis
  5. Panting (salivation)
  6. Heat Stroke


  1. Oedematous condition
  2. Ascites

Isotonic saline solution (Normal or physiological saline) is 0.9% NaCl in water. It is most widely used as replacement fluids & also used as maintenance fluid in animal fluid therapy.

Hypertonic saline solutions are used for the early treatment of hemorrhagic shock as they rapidly expand the blood volume.

3. Ringer Lactate Solution


  1. Mild acidosis
  2. Dehydration
  3. Burn (Shock)
  4. Peritonitis (Shock)


  1. Hepatic disorders
  2. Congestive heart failure
  3. Severe acidosis
  4. Anoxia due to shock
  5. Rumen acidosis
  6. Severe metabolic alkalosis

Ringer lactate is used as a volume expander & in all types of shock conditions except cardiogenic shock. It is useful in metabolic acidosis.

4. Mannitol

It is used as 20% solution

  1. To induce diuresis
  2. To decompensate intracranial pressure