Definition and Overview

Hypovolemic shock is a life-threatening condition caused by severe blood or fluid loss usually due to blunt traumatic injuries or internal bleeding. When at least 20% of the body’s blood or fluid supply is lost, the heart’s ability to pump an adequate amount of blood is severely compromised. Without enough blood supply, the risk of kidney and brain damage, gangrene of the legs or arms (which may create the need for an amputation), heart attack, and other organ damage is extremely high. In severe cases, the condition leads to death.

Hypovolemic shock, which is also referred to as haemorrhagic shock, is the most common type of shock. Other types include septic shock (caused by severe infections) and cardiogenic shock (caused by heart problems). The bleeding may be internal or external. Internal bleeding may occur within cavities, tissues, and organs of the body including the spinal canal, head, abdomen, and chest. It is much more challenging to diagnose when compared to external bleeding and may not be evident for many hours after it begins. External bleeding, on the other hand, is easy to recognise as blood coming from an open wound is readily seen.

Causes of Condition

Hypovolemic shock is caused by severe internal or external bleeding, which can be the result of the following:

  • Large wounds or cuts

  • Blunt traumatic injuries

  • Bleeding from the digestive tract

  • Ruptured ectopic pregnancy

  • Gynaecologic cancers that can result in excessive vaginal bleeding

  • Invasive and extensive surgical procedures

  • Severe burns leading to the loss of plasma

  • Heat stroke or heat exhaustion

  • Leukemia

Key Symptoms

Patients suffering from hypovolemic shock are at risk of serious complications because their body is unable to replace the amount of fluid they are losing. Without enough blood and fluid supply, cardiac output and blood pressure cannot be maintained. When this happens, cells start to malfunction and waste products quickly build up. Cells then begin to die and the worsening body environment leads to multiple organ failure.

There are often no advance warnings that could prompt the patient to seek immediate medical attention. Symptoms often occur when the condition is starting to disrupt bodily functions as various organs are left without enough blood and oxygen supply for an extended period.

Hypovolemic shock symptoms include:

  • Blue lips and fingernails

  • Cold, clammy, and pale skin

  • Confusion

  • Loss of consciousness

  • Rapid heart rate

  • Rapid, shallow breathing

  • General weakness

  • Anxiety

  • Low blood pressure

  • Reduced responsiveness

Meanwhile, patients suffering from internal bleeding and mild hypovolemic shock may experience the following:

  • Abdominal pain/swelling

  • Blood in the stool/urine

  • Black stool

  • Chest pain

  • Dizziness

  • Headaches

  • Nausea

  • Profuse sweating

  • Fatigue

Who to See and Types of Treatments Available

Patients showing signs of hypovolemic shock must be taken to a hospital emergency room as quickly as possible. Their treatment, however, often begins at an accident site or at home. A prehospital care team must work to stabilise the patient as well as prevent further injury and blood loss. This involves immobilising the patient, putting pressure on the wounds, and ensuring proper ventilation. Although such measures are very essential, transporting the patient to the hospital remains the most important for patients suffering from the condition. Delayed transport could be potentially harmful.

In the hospital, an intravenous line is immediately established to replace the lost blood and fluid as quickly as possible. Medicines such as epinephrine and dopamine are also used to increase blood pressure. Emergency doctors focus on maximising oxygen delivery, fluid resuscitation, restoring normal blood flow, and preventing further blood loss. They also work to stabilise any damages caused by the condition and treat any injury. Antibiotics are also provided to prevent bacterial infections and septic shock.

Doctors then perform various diagnostic tests to identify the underlying cause of shock and the severity of the condition. These tests may include:

  • Blood tests, to check liver and kidney function as well as electrolyte imbalances

  • Imaging tests, to visualise internal organs

  • Echocardiogram, to check the function of the heart

  • Endoscopy, to examine gastrointestinal organs

  • Radiographs, if long-bone fractures are suspected

  • Abdominal sonography, if traumatic abdominal injury is suspected

  • Pregnancy test, a standard test performed on female patients of childbearing age

  • CT scanning of the chest

Hypovolemic shock is always considered a medical emergency. The patient’s outlook depends on many factors, including:

  • The amount of blood/fluid loss

  • The speed at which blood or fluid is lost

  • The cause of the condition

  • Underlying medical conditions including kidney disease, diabetes, and previous stroke

  • The extent of injuries

  • If the patient is taking blood thinners

In general, patients suffering from severe shock, especially those who are either very old or very young, have poor prognosis and death in such cases is not uncommon. The best way to prevent life-threatening complications is to ensure that the patient receives immediate medical attention.

References:

  • Traumatic hypovolemic shock: Halt the downward spiral. Nursing, 40(10), 34–39. http://journals.lww.com/nursing/Fulltext/2010/10000/Traumatichypovolemicshock_Haltthe_downward.12.aspx

  • 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.

  • 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.

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