Ch.26 Bleeding Flashcards
The cardiovascular system is the main system responsible for supplying and maintaining adequate blood flow. It
consists of three parts:
• The pump (the heart)
• A container (the blood vessels that reach the cells of the body)
• The fluid (blood and body fluids)
All organs depend on the heart to provide a rich blood supply. For this reason, the heart muscle has several unique features. First, because the heart cannot tolerate a disruption of its blood flow for more than a few minutes, the heart muscle needs a rich and well-distributed blood supply. Second, the heart works as two paired pumps (FIGURE 26-2).
Each side of the heart has an upper chamber (atrium) and a lower chamber (ventricle), both of which pump blood.
Blood leaves each chamber of a normal heart through a__, which keeps the blood moving in the proper direction by preventing backflow.
one-way valve
The right side of the heart circulates blood from the body to the lungs. The left side of the heart circulates oxygen-rich blood from the lungs to the rest of the body. It is the more muscular of the two pumps because it must pump blood into the____ in order to reach all cells of the body.
aorta and arteries
As blood flows out of the heart, it passes into the aorta, the largest artery in the body. The arteries become smaller the farther they are from the heart. The smaller blood vessels that connect the arteries and capillaries are arterioles.
Capillaries are small tubes, with the diameter of a single red blood cell, that pass among all the cells in the body, linking the arterioles and the venules. Blood leaving the distal side of the capillaries flows into the venules. These small, thin-walled vessels empty into the veins, and the veins then empty into the inferior and superior vene cavae. This is the process that returns blood in the venous portion of the circulatory system to the heart. Oxygen and nutrients easily pass from the capillaries into the cells, and waste and carbon dioxide___ from the cells into the capillaries (FIGURE 26-3). This transportation system allows the body to rid itself of waste products.
diffuse
Blood contains red cells, white cells, platelets, and plasma (FIGURE 26-4). Red blood cells transport oxygen to the cells and transport carbon dioxide (a waste product of cellular metabolism) away from the cells to the lungs, where it is removed from the body during___. Platelets are the key to formation of blood clots. Blood clots are an important response from the body to control blood loss. In the body, blood clot formation depends on several factors: blood stasis, changes in the blood vessel wall (such as a wound), and the blood’s ability to clot (affected by disease processes or medications). When tissues are injured, platelets begin to collect at the site of injury; this causes red blood cells to become sticky and clump together. As the red blood cells begin to clump, a protein in plasma reinforces the developing clot by converting to a threadlike mesh that forms a clot. Medical conditions that interfere with the normal clotting process will be discussed later in this chapter.
exhalation
The____ monitors the body’s needs and adjusts the blood flow by constricting or dilating blood vessels as required. During an emergency, the__ automatically redirects blood away from other organs to the heart, brain, lungs, and kidneys. Thus, the cardiovascular system adapts to changing conditions in the body to maintain homeostasis and perfusion. If blood volume is significantly diminished and the system fails to provide sufficient circulation for every body part to perform its function, then hypoperfusion, or shock, results. See Chapter 13, Shock, for a more detailed discussion of this process.
autonomic nervous system
____is the circulation of blood within an organ or tissue to allow it to meet the cells’ current needs for oxygen, nutrients, and waste removal. Blood enters an organ or tissue first through the arteries, then the arterioles, and finally, the capillary beds (FIGURE 26-5). As it passes through the capillaries, the blood delivers nutrients and oxygen to the surrounding cells and picks up the wastes they have generated.
Perfusion
___must pass through the cardiovascular system fast enough to maintain adequate circulation throughout the body and to avoid clotting, yet slow enough to allow each cell time to exchange oxygen and nutrients for carbon dioxide and other waste products. Although some tissues never rest and require a constant blood supply, most require a large volume of circulating blood only intermittently, with less required when at rest. For example, skeletal muscles require a minimal blood supply during sleep, as opposed to a large blood supply during exercise. Another example is the gastrointestinal tract, which requires a high flow of blood after a meal. After digestion is completed, however, the gastrointestinal tract functions well with a small fraction of that blood flow.
Blood
All organs and organ systems of the human body depend on adequate___ to function properly. Some organs require a rich supply of blood and do not tolerate interruption of blood supply for even a few minutes without sustaining damage. If___ to these organs is interrupted, then dysfunction and failure of that organ system will occur. The death of an organ system can quickly lead to the death of the patient. Emergency medical care is designed to support adequate perfusion of these critical organs and organ systems, listed in TABLE 26-1, until the patient arrives at the hospital.
perfusion
The heart requires constant___ to function optimally; without it, cells in the brain and spinal cord start to die after 4 to 6 minutes. (Remember that cells of the central nervous system do not have the capacity to regenerate.) Without adequate__, the lungs can survive only 15 to 20 minutes and kidneys can be damaged after 45 minutes. Skeletal muscle demonstrates evidence of injury after 2 to 3 hours of inadequate perfusion, while the gastrointestinal tract can tolerate slightly longer periods. These times are based on a normal core body temperature (98.6°F [37.0°C]). An organ or tissue that is kept at a considerably lower temperature may be better able to resist damage from hypoperfusion.
perfusion
___means bleeding. External bleeding is visible hemorrhage. Examples include nosebleeds and bleeding from open wounds. As an EMT, you must understand how to control external bleeding.
Hemorrhage
With serious external bleeding, it is often difficult to determine the amount of blood loss because blood will look different on different surfaces, such as when it is absorbed in clothing, when it has been diluted in water, or when the environment is dark. It is important to estimate the amount of external blood loss; however, treatment should be based on the patient’s presentation and__
mechanism of injury (MOl).
The typical adult male body contains approximately____ of blood per kilogram of body weight, whereas the adult female
body contains approximately____ of blood per kilogram of body weight. Therefore, a typical adult man weighing 175 pounds (79 kg) has a total blood volume of about 10 to 12 pints (6 L). The body cannot tolerate an acute blood loss of greater than 20% of this total blood volume, or more than 2 pints (approximately 1 L) in the average adult. With significant blood loss, adverse changes in vital signs will occur, including increased heart and respiratory rates and decreased blood pressure. Because infants and children have less blood volume compared with adults, these effects are seen with smaller amounts of blood loss. For example, a 1-year-old has a typical total blood volume of about 27 oz (800 mL); the child will show significant symptoms of blood loss after only 3 to 6 oz (100 to 200 mL) of blood loss, or less than half the volume of liquid in a 12-oz (350-mL) can of soda.
70 mL
65 mL
How well a patient’s body can compensate for blood loss is related to how rapidly the blood loss occurs. A healthy adult can comfortably donate ____within 15 to 20 minutes and adapt well to this decrease in blood volume. If this volume of blood loss occurs during a much shorter period, however, symptoms of hypovolemic shock, a condition in which low blood volume results in inadequate perfusion and even death, might develop. The age and preexisting health of the patient should also be considered
In any situation, severe blood loss presents an immediate life threat. Your priority is to quickly control major external
bleeding, even before you address airway and breathing concerns.
1 unit, or roughly 1 pint (500 mL) of blood
Injuries and some illnesses can disrupt blood vessels and cause external bleeding. You should consider bleeding to be severe if any of the following conditions exist:
• The patient has a poor general appearance and has no response to external stimuli.
• Assessment reveals signs and symptoms of shock (hypoperfusion).
• You note a significant amount of blood loss.
• The blood loss is rapid and ongoing.
• You cannot control the bleeding
• The bleeding is associated with a significant MOl.
Typically,___ bleeding from an open artery is bright red (because it is oxygen rich) and spurts in time with the pulse.
The pressure that causes the blood to spurt also makes this type of bleeding difficult to control. As the amount of blood circulating in the body drops, so does the patient’s blood pressure and, eventually, the arterial spurting.
arterial
___bleeding from an open vein is darker than arterial blood (because it is oxygen poor) and can flow slowly or rapidly, depending on the size of the vein. Because it is under less pressure, most venous blood does not spurt and is easier to manage; however, it can be profuse and life threatening.
Venous
___bleeding from damaged capillary vessels is dark red and oozes from a wound steadily but slowly. Venous and capillary blood is more likely to clot spontaneously than arterial blood
Capillary
On its own, bleeding tends to stop rather quickly, within about 10 minutes, in response to internal mechanisms and exposure to air. When a person’s skin is broken, blood flows rapidly from the open blood vessel. Soon afterward, the cut ends of the blood vessel begin to narrow (vasoconstriction), reducing the amount of bleeding. Then a clot forms, plugging the hole and sealing the injured portions of the blood vessel. This process is called___. With a severe injury, the damage to the blood vessel may be so great that a clot cannot completely block the hole. Bleeding will never stop if an effective clot does not form, unless the injured blood vessel is completely cut off from the main blood supply by direct pressure or a tourniquet.
coagulation
Despite the efficiency of the circulatory system, it may fail in certain situations. Movement, disease process, certain medications (such as blood thinners), removal of bandages, the external environment, or body temperature commonly affect the blood’s clotting factors. Occasionally, blood loss is very rapid. In these cases, the patient might die before clotting occurs.
A small portion of the population lacks one or more of the blood’s clotting factors, a condition called__. There are
several forms of hemophilia, most of which are hereditary and some of which are severe. Sometimes bleeding occurs spontaneously in patients with hemophilia. Because the patient’s blood does not clot effectively, all injuries, no matter how trivial, are potentially serious. Transport any injured patient with hemophilia immediately.
hemophilia
If a bandage has already been applied to control bleeding before your arrival on the scene, obtain a description of the wound and the amount of bleeding from the patient or bystanders. If blood has seeped through the dressing, do not remove it; most likely the clotting process has already begun and removing the dressing will disturb the clot. Instead, apply a clean dressing on top of the first one to reinforce it. You can also observe the old dressing to estimate the amount of blood loss.
Words of wisdom :)
___is any bleeding that occurs in a cavity or space inside the body. Internal bleeding can be very serious, especially because it is not easy to detect immediately. Injury or damage to internal organs commonly results in extensive internal bleeding, which can cause hypovolemic shock before you realize the extent of blood loss. A person with a bleeding stomach ulcer may sustain a large amount of blood loss very quickly. Similarly, a person who has a lacerated liver or a ruptured spleen may sustain a considerable amount of blood loss within the abdomen, yet the patient may have no outward signs of bleeding
Broken bones also may cause serious internal blood loss. A broken femur can easily result in the loss of 2 pints (approximately 1 L) or more of blood into the soft tissues of the thigh. Often, the only signs of such bleeding are local swelling and bruising (called a contusion, or ecchymosis) caused by the accumulation of blood around the ends of the broken bone. Severe pelvic fractures may result in life-threatening hemorrhage.
Always be alert to the possibility of internal bleeding. Assess the patient for related signs and symptoms, particularly if the MOl is significant. If you suspect that a patient is bleeding internally, treat for shock and promptly transport him or her to the hospital.
Internal bleeding
A bruise from an injury that causes bleeding beneath the skin without breaking the skin; also see ecchymosis
Contusion
A buildup of blood beneath the skin that produces a characteristic blue or black discoloration as the result of an injury
Ecchymosis