Hypovolemic shock is a medical emergency that happens when your body loses too much blood or fluid. It makes it very difficult for your heart to beat efficiently and can lead to organ failure.

Hypovolemic shock is a life-threatening condition that results when you lose more than 15 percent of your body’s blood or fluid supply and your heart function is impaired. It can occur due to any type of fluid loss, for example, as a result of dehydration or diarrhea.

Severe fluid loss makes it difficult for the heart to pump enough blood to your body. As the fluid loss increases, hypovolemic shock can lead to organ failure. This requires immediate emergency medical attention.

The symptoms of hypovolemic shock vary with the severity of the fluid loss. However, all symptoms of shock are life-threatening and need emergency medical treatment.

Generally, symptoms may include:

  • thirst
  • muscle cramps
  • decrease in blood pressure, or poor blood supply throughout the body

You may experience pain in your abdomen or your chest. You may also experience some neurological symptoms like confusion, agitation, or lethargy (drowsiness), which occur due to decreased blood flow to the brain.

Older adults are highly susceptible to shock, and children may not show symptoms of shock until they reach a more severe stage.

Hypovolemic shock occurs in stages, and the symptoms may change as the condition progresses.

The stages of the condition are:

Class 1

At this stage, you would be losing less than 15 percent of your blood volume, which is about 750 milliliters (mL).

Your blood pressure and breathing will still appear normal, but you may begin to suddenly feel anxious and your skin may look pale.

Class 2

The blood volume loss in this stage ranges between 15 and 30 percent, which is typically 750 to 1,500 mL. Your heart rate and breathing may get faster. Your blood pulse pressure may narrow. Your systolic blood pressure (the top number in a blood pressure measurement) may still be normal.

Your blood pressure at the beginning of this stage may still be normal, though the bottom number of the measurement, the diastolic pressure, may be high.

Class 3

At this stage, you lose 30 to 40 percent of your blood volume, which is between 1,500 and 2,000 mL. You’ll experience a major drop in your blood pressure and begin to see changes to your mental status.

Your heart rate will rise above 120 beats per minute (bpm), your breathing will become faster, and you’ll see a decrease in the amount you urinate.

Class 4

Once you’ve experienced blood volume loss of more than 40 percent, your condition becomes critical. Your pulse pressure will be really low, and your heart will beat faster at more than 120 bpm.

You may experience:

Your mental status will be obviously abnormal, and you’ll stop urinating almost completely. You may experience external and internal bleeding from areas in your body.

When the fluid loss occurs exclusively as a result of severe blood loss, a more specific term is used to describe the condition. This is called “hemorrhagic shock.”

Depending on the location of the bleeding inside the body, the signs and symptoms may include:

If you have any signs of hemorrhaging, you or someone near you must seek medical attention immediately.

While some symptoms like abdominal pain and sweating can point to something less urgent like a stomach virus, you should seek immediate medical attention when seeing groupings of these symptoms together.

This is especially true for the more serious symptoms. The longer you wait, the more damage can be done to your tissues and organs.

Hypovolemic shock results from significant and sudden blood or fluid losses within your body. In addition to actual blood loss, the loss of body fluids can cause a decrease in blood volume.

Different causes of hypovolemic shock include:

Blood carries oxygen and other essential substances to your organs and tissues. When heavy bleeding or fluid loss occurs, there’s not enough blood in circulation for the heart to be an effective pump. This is hypovolemic shock.

As you lose more fluid, you no longer have enough blood to effectively supply oxygen to your tissues. To make up for this, your body sends the remaining blood supply to the most important organs: the brain and the heart.

This means the rest of the body is even more in need of oxygen, and your tissues respond by producing lactic acid. As a result, the body enters acidosis, which is when your body fluid contains too much acid. Without timely treatment, this can lead to death.

Call 911

If you or someone around you is experiencing any symptoms of hypovolemic shock, call 911 or your local emergency number, or go to the nearest emergency department. Untreated hypovolemic shock will lead to death.

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If you are near someone else who is experiencing shock symptoms, do the following until first responders arrive:

  • Check for the person’s pulse if they are unconscious.
  • If there is no pulse, begin CPR.
  • Avoid moving the person if you suspect a head, neck, or back injury.
  • Keep the person warm to avoid hypothermia.
  • Do not give the person fluids by mouth.

Click here for information on how to perform CPR.

Do not elevate their head. Remove any visible dirt or debris from the injury site. Do not remove embedded:

  • glass
  • knife
  • stick
  • arrow
  • any other object stuck in the wound

If the area is clear of debris and no visible object is sticking out from it, tie fabric, such as a shirt, towel, or blanket, around the site of injury to minimize blood loss. Apply pressure to the area. If you can, tie or tape the fabric to the injury.

A lack of blood and fluid in your body can lead to the following complications:

The effects of hypovolemic shock depend on the speed at which you’re losing blood or fluids and the amount of blood or fluids you’re losing. The extent of your injuries can also determine your chances of survival.

Certain chronic medical conditions can increase the likelihood that you’ll experience more complications from hypovolemic shock. These may include:

There are often no advance warnings of shock. Instead, symptoms tend to arise only when you’re already experiencing the condition.

A physical examination can reveal signs of shock, such as low blood pressure and rapid heartbeat. A person experiencing shock may also be less responsive when asked questions by the emergency room doctor.

Heavy bleeding is immediately recognizable, but internal bleeding sometimes is not found until you show signs of hemorrhagic shock.

In addition to physical symptoms, your doctor may use a variety of testing methods to confirm that you’re experiencing hypovolemic shock. These include:

  • blood testing to check the severity of the hypovolemic loss
  • trauma ultrasound known as Focused Assessment with Sonography for Trauma (FAST)
  • CT scan to visualize body organs
  • echocardiogram, an ultrasound of the heart

Your doctor may order other tests based on your symptoms.

Once at a hospital, a person suspected of having hypovolemic shock will receive fluids or blood products via an intravenous (IV) line, to replenish the blood loss and improve circulation.

Treatment revolves around:

  • controlling loss of fluid and blood
  • replacing what’s been lost
  • stabilizing damage that both caused and resulted from the hypovolemic shock
  • treating the injury or illness that caused the shock, if possible

Treatments may include:

Doctors may also administer medications that increase the heart’s pumping strength to improve circulation and get blood where it’s needed. These include:

  • dopamine
  • dobutamine
  • epinephrine
  • norepinephrine

Antibiotics may be administered to prevent septic shock and bacterial infections. Close cardiac monitoring will determine the effectiveness of the treatment you receive.

Hypovolemic shock is dangerous for everyone, but it can be particularly dangerous in older adults. Older adults tend to experience hypovolemic shock more commonly than their younger counterparts.

As people age, they may have more health conditions that can reduce their tolerance to shock. Older people are also more likely to take anticoagulants, which are medications that help prevent blood clots.

This means that if they go into hypovolemic shock, which then develops into hemorrhagic shock, they are at a higher risk of serious complications and even death.

Recovery from hypovolemic shock depends on factors like the patient’s prior medical conditions and the degree of the shock itself.

Those with milder degrees of shock may have an easier time recovering. If you progress to the third or fourth stage, severe organ damage can result. This makes it much harder to recover, and continued medical interventions may be needed. In severe cases, organ damage may be irreversible.

Overall, your outlook will depend on the amount of blood you lost and the type of injury you sustained. The outlook is best in patients with good overall health who haven’t had severe blood loss.