Hypovolemic Shock

Medically Reviewed by James Beckerman, MD, FACC on November 03, 2022
4 min read

Hypovolemic shock is a dangerous condition that happens when you suddenly lose a lot of blood or fluids from your body. This drops your blood volume, the amount of blood circulating in your body. That’s why it’s also known as low-volume shock.

Hypovolemic shock is a life-threatening emergency. Blood helps hold your body temperature steady, forms blood clots, and moves oxygen and nutrients to all of your cells. If your blood volume gets too low, your organs won't be able to keep working.

The most common cause of hypovolemic shock is blood loss when a major blood vessel bursts or when you’re seriously injured. This is called hemorrhagic shock.

You can also get it from heavy bleeding related to pregnancy, from burns, or even from severe vomiting and diarrhea.

How hypovolemic shock shows up can depend on a number of things, including:

  • Your age
  • Your past medical care and overall health
  • The cause of the shock or the source of the injury
  • How quickly you lost the blood or fluids
  • How much your blood volume has dropped

With an injury, the most obvious sign of hypovolemic shock is a lot of bleeding. But you won't see it when the bleeding is happening inside your body because of an aortic aneurysm, organ damage, or ectopic pregnancy.

Other signs of hypovolemic shock include:

Causes of hypovolemic shock that involve bleeding include:

  • Broken bones around your hips
  • Cuts on your head and neck
  • Damage to organs in your belly, including your spleenliver, and kidneys, because of a car accident or a bad fall
  • A tear in your heart or a large blood vessel, or a weakened spot in a large blood vessel that could burst
  • Problems with your digestive tract, such as ulcers
  • An embryo growing outside a woman’s uterus (ectopic pregnancy)
  • The placenta peeling away from the wall of a pregnant woman’s uterus (placental abruption)
  • A ruptured ovarian cyst
  • Heavy bleeding during labor or delivery, or in the following 24 hours
  • A disorder in which the tissue that usually lines a woman’s uterus grows outside it (endometriosis)

Causes that don’t involve bleeding include:

  • Dehydration
  • Diarrhea and vomiting
  • High fever
  • Severe sweating
  • Other gastrointestinal problems like stoma or fistulas
  • Kidney disease and diuretics
  • Fluids getting stuck in one part of your body because of a condition like pancreatitis or intestinal blockage

There are four stages of hypovolemic shock:

  1. Loss of up to 750 cubic centimeters (cc) or milliliters (mL) of blood, up to 15% of your total volume. Your blood vessels narrow slightly to keep blood pressure up. Your heart rate is normal, and your body makes as much urine as usual.
  2. Loss of 750 to 1,500 cc of blood. Your heart rate rises. Your body starts to pull blood away from your limbs and intestines and sends it to vital organs like your heart and brain. Your blood pressure and urine are regular, but you may feel some anxiety.
  3. Loss of 1,500 to 2,000 cc of blood, about a half-gallon. Your blood pressure drops. Your body stops making as much pee. Your limbs are cold and clammy, and your skin is pale. You may become confused or flustered.
  4. Loss of more than 2,000 cc of blood, more than 40% of your total blood volume. Your heart is racing, but you feel sluggish. Your blood pressure is very low. Your body is making little or no pee.

Your doctor will check your temperature, pulse, breathing, and blood pressure. They'll check the color and feel of your skin. If you're awake and alert, they'll ask about past medical issues and your overall health.

If you could be in shock because of an ectopic pregnancy or something else related to your reproductive organs, the health care team will also do a pregnancy test and ask about your last menstrual period and any recent vaginal bleeding.

You may need more tests, including:

  • Imaging studies such as X-rays, ultrasounds, or CT scans
  • Blood and urine tests
  • Heart tests like echocardiogram and electrocardiogram (ECG)

The first step is to get you to the emergency room as quickly as possible. Along the way, someone should try to stop any visible bleeding.

Your medical team will try to:

  • Get as much oxygen as possible to all parts of your body
  • Stop, or at least control, blood loss
  • Replace blood and other fluids

You’ll get fluids through an IV, a bag of liquid attached to a needle that goes directly into a vein. Most people who lose more than 30% of their blood volume will also need a blood transfusion. Many will need some kind of surgery, especially if they have internal or gynecological bleeding.

Hypovolemic shock can lead to complications such as:

  • Infection (if you were injured)
  • Damage to your kidneys and other organs
  • Death

The outcome depends on how serious your condition is when you start treatment, how much blood you lost, how quickly blood and fluids are replaced, and whether you have any other issues or complications.