EMT Lecture: Bleeding and the Cardiovascular System

Flashcards covering the vocabulary, physiology, and emergency treatment of bleeding and cardiovascular trauma based on EMT training materials.

Hemorrhage

Bleeding, which is the single most preventable cause of traumatic death.

Shock (hypoperfusion)

A condition in which the cardiovascular system fails to provide sufficient circulation for every body part to perform its function, resulting from low blood volume.

Perfusion

The circulation of blood within an organ or tissue to allow it to meet the cells' current needs for oxygen, nutrients, and waste removal.

Cardiovascular system components

Consists of three parts: the pump (heart), the container (blood vessels), and the fluid (blood and body fluids).

Atrium

An upper chamber of the heart; each side of the heart has one.

Ventricle

A lower chamber of the heart; each side of the heart has one.

Aorta

The largest artery in the body, into which the left ventricle pumps oxygen-rich blood.

Arterioles

Smaller blood vessels that connect the arteries and capillaries.

Capillaries

Small tubes the diameter of a single red blood cell that link arterioles and venules, allowing for the exchange of nutrients, waste, oxygen, and carbon dioxide.

Venules

Small, thin-walled vessels that receive blood from the distal side of the capillaries and empty into the veins.

Venae cavae

The inferior and superior vessels that return blood from the venous portion of the circulatory system back to the heart.

Red blood cells

Blood components responsible for transporting oxygen to the cells and carbon dioxide away from the cells to the lungs.

Platelets

The key components in the blood for the formation of blood clots to control blood loss.

Plasma

The fluid portion of blood that contains proteins to reinforce a developing clot by converting into a threadlike mesh.

Coagulation

The process where blood vessels narrow and a clot forms to plug a hole and seal injured portions of the vessel.

Hemophilia

A condition, often hereditary, where a person lacks one or more of the blood's clotting factors, making all injuries potentially serious.

Adult total blood volume

The typical adult has an average volume of $9$ to $10$ pints ($5$ to $5.5\,L$).

Significant blood loss (Adult)

An acute loss of greater than $20\%$ of total blood volume, or more than $2$ pints (approximately $1\,L$).

Significant blood loss (Infant)

Significant symptoms appear after only $3$ to $6\,oz$ ($100$ to $200\,mL$) of loss in a child with a total volume of $27\,oz$ ($800\,mL$).

Brain and spinal cord perfusion tolerance

Critical organs where cells start to die after $4$ to $6$ minutes without a steady supply of oxygenated blood.

Kidney perfusion tolerance

Organs that can be damaged after $45$ minutes of inadequate perfusion.

Skeletal muscle perfusion tolerance

Tissue that demonstrates evidence of injury after $2$ to $3$ hours of inadequate perfusion.

Arterial bleeding

Bright red, oxygen-rich blood that spurts in time with the pulse and is often difficult to control due to high pressure.

Venous bleeding

Oxygen-poor, darker blood that flows steadily or rapidly; it does not spurt and is generally easier to manage than arterial bleeding.

Capillary bleeding

Dark red blood that oozes from a wound steadily but slowly.

Ecchymosis

Bruising or discoloration (also called a contusion) caused by the accumulation of blood around broken bone ends or in soft tissues.

Hematemesis

The vomiting of blood, which may be bright red, dark red, or look like coffee grounds if partially digested.

Melena

Unusually dark, foul-smelling, tarry stool that contains digested blood.

Hemoptysis

The coughing up of bright red blood.

Hematuria

The presence of blood in the urine, suggesting serious internal injury or disease.

Hematoma

A mass of blood that has collected in the soft tissues beneath the skin.

Epistaxis

Common emergency term for a nosebleed.

Tourniquet

A device applied at least $2$ to $3$ inches ($5$ to $8\,cm$) proximal to a wound to control substantial extremity bleeding that direct pressure cannot stop.

Hemostatic dressing

A dressing impregnated with a chemical compound that slows or stops bleeding by promoting clot formation.

Junctional tourniquet

A device used for life-threatening bleeding in areas where standard tourniquets are not possible, such as the groin or axilla.

Pelvic binder

A type of splint used to reduce the width of and stabilize suspected unstable pelvic fractures to help control internal bleeding.

Pediatric shock BP threshold

In children $9$ years and younger, a systolic blood pressure less than $70\,mm\,Hg + (2 \times \text{age in years})$.