Hypovolemic shock

Definition

Hypovolemic shock is an emergency condition in which severe blood and fluid loss make the heart unable to pump enough blood to the body. This type of shock can cause many organs to stop working.

Alternative Names

Shock - hypovolemic

Causes, incidence, and risk factors

Losing about 1/5 or more of the normal amount of blood in your body causes hypovolemic shock.

Blood loss can be due to:

• Bleeding from cuts
• Bleeding from other injuries
• Internal bleeding, such as in the gastrointestinal tract

The amount of circulating blood in your body may drop when you lose too many other body fluids, which can happen with:

• Burns
• Diarrhea
• Excessive perspiration
• Vomiting

Symptoms

• Anxiety or agitation
• Cool, clammy skin
• Confusion
• Decreased or no urine output
• General weakness
• Pale skin color (pallor)
• Rapid breathing
• Sweating, moist skin
• Unconsciousness

The greater and more rapid the blood loss, the more severe the symptoms of shock.

Signs and tests

An examination shows signs of shock, including:

• Low blood pressure
• Low body temperature
• Rapid pulse, often weak and thready

Tests that may be done include:

• Blood chemistry, including kidney function tests
• Complete blood count (CBC)
• CT scan, ultrasound, or x-ray of suspected areas
• Echocardiogram
• Endoscopy
• Right heart (Swan-Ganz) catheterization
• Urinary catheterization (tube placed into the bladder to measure urine output)

This list may not be all-inclusive.

Treatment

Get immediate medical help. In the meantime, follow these steps:

• Keep the person comfortable and warm (to avoid hypothermia).
• Have the person lie flat with the feet lifted about 12 inches to increase circulation. However, if the person has a head, neck, back, or leg injury, do not change the person's position unless he or she is in immediate danger.
• Do not give fluids by mouth.
• If person is having an allergic reaction, treat the allergic reaction, if you know how.
• If the person must be carried, try to keep him or her flat, with the head down and feet lifted. Stabilize the head and neck before moving a person with a suspected spinal injury.

The goal of hospital treatment is to replace blood and fluids. An intravenous (IV) line will be put into the person's arm to allow blood or blood products to be given.

Medicines such as dopamine, dobutamine, epinephrine, and norepinephrine may be needed to increase blood pressure and the amount of blood pumped out of the heart (cardiac output).

Other methods that may be used to manage shock and monitor the response to treatment include:

• Heart monitoring, including Swan-Ganz catheterization
• Urinary catheter to collect and monitor how much urine is produced

Support Groups

Expectations (prognosis)

Hypovolemic shock is always a medical emergency. However, symptoms and outcomes can vary depending on:

• Amount of blood/fluid volume lost
• Rate of blood /fluid loss
• Illness or injury causing the loss
• Underlying chronic medication conditions, such as diabetes and heart, lung, and kidney disease

In general, patients with milder degrees of shock tend to do better than those with more severe shock. In cases of severe hypovolemic shock, death is possible even with immediate medical attention. The elderly are more likely to have poor outcomes from shock.

Complications

• Kidney damage
• Brain damage
• Gangrene of arms or legs, sometimes leading to amputation
• Heart attack
• Severe shock can lead to death

Calling your health care provider

Hypovolemic shock is a medical emergency. Call the local emergency number (such as 911) or take the person to the emergency room.

Prevention

Preventing shock is easier than trying to treat it once it happens. Quickly treating the cause will reduce the risk of developing severe shock. Early first aid can help control shock.

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References

Maier RV. Approach to the patient with shock. In: Fauci AS, Harrison TR, eds. Harrison's Principles of Internal Medicine. 17th ed. New York, NY: McGraw Hill; 2008:chap 264.

Spaniol JR, Knight AR, Zebley JL, Anderson D, Pierce JD. Fluid resuscitation therapy for hemorrhagic shock. J Trauma Nurs. 2007;14:152-156.

Jones AE, Kline JA. Shock. In: Marx JA, Hockberger RS, Walls RM, et al, eds. Rosen’s Emergency Medicine: Concepts and Clinical Practice. 7th ed. Philadelphia, Pa: Mosby Elsevier; 2009:chap 4.

Tarrant AM, Ryan MF, Hamilton PA, Bejaminov O. A pictorial review of hypovolaemic shock in adults. Br J Radiol. 2008;81:252-257.

den Uil CA, Klijn E, Lagrand WK, Brugts JJ, Ince C, Spronk PE, Simoons ML. The microcirculation in health and critical disease. Prog Cardiovasc Dis. 2008;51:161-170.