Hypovolemia

What is hypovolaemia?

Hypovolaemia is the decrease in blood volume due to loss of blood, plasma and/or plasma water, which is encountered in cases of severe dehydration or blood loss. This eventually results in a loss of intravascular content and limits tissue perfusion. It can be fatal if left untreated.

What are its main signs and symptoms?

The common signs and symptoms of hypovolaemia include:

• Generalised weakness
• Paleness of skin (pallor)
• Cool, clammy skin or sweating, moist skin
• Rapid breathing
• Anxiety or agitation
• Low blood pressure (hypotension)
• Low or no urine output
• State of confusion
• Unconsciousness

What are its main causes?

Hypovolemia can be caused by:

• Loss of body fluids due to the following:
  • Severe persistent diarrhoea and vomiting
  • Extensive burns
  • Excessive sweating
  • Use of diuretics
  • Increased urination as seen with kidney diseases 

• Blood loss due to the following:
  • Bleeding from cuts or other injuries
  • Internal bleeding, such as in the digestive tract
  • Clotting abnormalities
  • Surgeries

How is it diagnosed and treated?

The diagnosis is mainly considered by the physician based on signs and symptoms and a complete physical examination. Further evaluation is done on the basis of the following tests:

• Blood test to evaluate kidney function, complete blood count (CBC) and damage to the heart muscles
• X-ray
• Ultrasound
• Computed tomography (CT) scan
• Endoscopy
• Echocardiogram
• Right heart catheterisation
• Urinary catheterisation

Treatment of hypovolaemia includes:

• The first line of treatment would be measured to replace blood and fluids, which can be achieved by giving various oral rehydrating liquids or intravenous (IV – through veins) transfusion of blood or fluids depending upon the cause of hypovolaemia. Further, to avoid hypothermia, the individual should be made comfortable and warm.
• In case the cause is an allergy, anti-allergens should be given.
• In severe cases, to increase blood pressure and cardiac output (the amount of blood pumped out of the heart), medications such as norepinephrine, dopamine, epinephrine or dobutamine may be given.

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