What Is Hemorrhage? - Definition & Symptoms

Lesson Transcript
Instructor: Ian Lord

Ian is a 3D printing and digital design entrepreneur with over five years of professional experience. After six years of aircrew service in the Air Force, he earned his MBA from the University of Phoenix following a BS from the University of Maryland. He is also a real estate investor, board gamer and homebrewer.

Hemorrhage is a medical term used to describe the rupture of blood vessels, often due to injury, which results in excessive bleeding. Learn about the definition, symptoms, and classes of hemorrhage. Updated: 10/14/2021

Hemorrhage Defined

Bill is a bloody mess as he is brought into the emergency room. He was using a chainsaw that kicked back while cutting a fallen tree branch in his backyard, and now has a deep cut across his torso. The ER team has seen far worse and can save his life, but his injury is a good example of a hemorrhage. In simplest terms, a hemorrhage is when blood vessels rupture, often due to an injury, resulting in excessive bleeding. A hemorrhage can be either external or internal, which is harder to detect. Let's take a look at the Advanced Trauma Life Support (ATLS) classification of hemorrhage, along with the symptoms present in each class.

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  • 0:02 Hemorrhage Defined
  • 0:53 Hemorrhage: Class 1
  • 1:19 Hemorrhage: Class 2
  • 1:59 Hemorrhage: Class 3
  • 2:25 Hemorrhage: Class 4
  • 2:51 Lesson Summary
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Hemorrhage Classes

ATLS classes divide hemorrhage into four classes, based on the amount of blood lost. These four classes increase in severity, with Class 1 the least severe and Class 4 the most dangerous.

Hemorrhage: Class 1

The adult human body contains roughly five liters of blood. In the Class 1, or minimal stage of hemorrhage, there is less than 15%, or approximately 750ml, of blood loss. Patients still tend to have normal pulse rates and blood pressure. They are unlikely to have any further major medical problems because of the blood loss. Consider that a blood donation is about 450 to 500ml, and has very few side effects.

Hemorrhage: Class 2

Class 2, or mild hemorrhage, is defined as a 15 to 30% blood loss amount. In an adult, this would be equivalent to losing 750 to 1500 ml, which is about the equivalent of one or two bottles of wine.

Symptoms include a rapid heart rate, decreased pulse in the arms and legs, and an increased respiratory rate. The patient might be irritable or mentally altered and combative. His skin might be cooler to the touch and have delayed capillary refill. Urine production may be decreased, and have a higher concentration of other substances than normal. Thankfully for Bill, quick medical treatment means that his bleeding didn't progress beyond this class.

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