Chap 25 Flashcards
Different parts of a vessel
External elastic membrane Smooth muscle Internal elastic membrane Lumen Endothelium
Valve- only in veins
Capillaries- just has endothelium
Functions of blood
Transports gases Nutrition Excretion Protection Regulation
hemorrhage
Bleeding, especially severe bleeding
Hemorrhage is the major cause of shock in trauma
Arterial bleeding
Bleeding from an artery, which is characterized by bright red blood that is rapid, profuse and difficult to control
Spurting Blood
Pulsating flow
Bright red color
Venous bleeding
Bleeding from a vein, which is characterized by dark red or maroon blood and a steady, easy to control flow
Steady, slow flow
Dark red color
Capillaries
Small vessels that are under far less pressure and can be easily controlled. Superficial wounds to the surface of the skin
Bleeding is under very low pressure and produces only a slow ooze from the wound. Typically ceases with out any intervention
Sometimes occurs over large areas so risk of infection is high
Slow, even flow
Junctional hemorrhage
Occurs where the appendages of the body connect to the trunk. In these locations large arteries and veins tend to be less well protected and particularly vulnerable to traumatic forces. The neck both armpits and both sides of the groin are sites were massive bleading is likely
Affects of hypothermia on blood
Affects ability to clot decreases. The colder a patient gets, the more likely coagulopathy or impaired ability to clot. Hypoperfused slowly lose their ability to generate heat through metabolism and their ability to conserve heat through blood flow
Compressible
For the most part, external hemorrhage is “compressible”, that is it can be controlled by compressing the tissue around the wound or the vessel that is bleeding or both.
Late signs of shock
Thirst, dilated pupils, and cyanosis around the lips and nail beds
Anaphylactic and neurogenic shock
Skin is typically warm, flushed and dry because the circulatory system has lost the ability to constrict blood vessels in the skin
Major methods of controlling external bleeding
Direct pressure
Elevation of a limb
Hemostatic agent
Tourniquet
Pressure dressing
A bulky dressing held in position with a tightly wrapped bandage, which applies pressure to help control bleeding
Elevation
Gravity helps reduce the blood pressure in the extremity, slowing bleeding. Don’t use this method if you suspect possible muscle skeletal injuries, impales objects in extremity or spine injury as the movement of broken bone ends or penetrating objects can further damage the tissue
Hemostatic agents
Substances applied as powders, dressings, glaze or bandages to open wounds to stop bleeding
Placement of tourniquet
2 inches above bleed
Make shift tourniquets
Two inches wide
Several layers thick
Bystanders tourniquets
If the EMT determines that the bleeding is not severe and other means would control it, medical direction may be contacted about removing the tourniquet
If you find that the tourniquet spoiled by a layperson has not stopped the bleeding, immediately apply direct pressure and remove it.
Splinting for bleeding control
Air splint may he used to control internal and external as long as no suspected bone injury. Air splints are most effective for venous and capillary bleeding but not usually effective for high pressure bleeding caused by artery bleeds unless arterial pressure has decreased below that of the splint
Cold applications
Cold minimizes swelling, reduce pain and reduces the bleeding by constricting the blood vessels.
Don’t apply directly to skin. don’t leave in place longer than 20 minutes
Head injury
Traumatic injuries resulting in a fractured skull may cause bleeding or loss of cerebrospinal fluid (CSF) from the ears or nose. Head injury results in increased pressure within the skull, which forces fluid out of the cranial cavity. You should not attempt to stop this bleeding or fluid loss as doing so may increase the pressure in the skull. Do not apply pressure to the ears or nose. Allow he drainage to flow freely using a gauze pad to collect it
Nosebleeds
(epistaxis)
Tiny capillaries in nose may burst because of increased blood pressure, sinus infection, or digital trauma (nose picking).
Steps
- Patient sit down and lean forward
- Apply or instruct patient to apply direct pressure to the fleshy portion around the nostrils
- Keep patient calm and quiet
- Don’t let the patient lean back. This allows the blood to flow down the esophagus to the stomach causing nausea and vomiting
- If patient goes unconscious, place in the recovery position
Mechanisms for blunt trauma
Falls
Motor vehicle or motorcycles crashes
Auto-pedestrian collisions
Blast injuries
Mechanisms for penetrating trauma
Gunshots
stab wounds
impaled objects
Compensated shock
The body senses the decrease in profusion and attempts to compensate for it. the body is able to compensate the work and patient maintains his blood pressure.
Constriction of the peripheral circulation(to redirect blood to the vital core organs) results in pale, cool skin and in infants and children, increased capillary refill time
Decompensated shock
Point when the body can no longer compensate for the low blood volume or lack of perfusion. Late signs of shock, such as falling blood pressure, develop.
Hemorrhagic shock
shock resulting from blood loss
Hypovolemic shock may also be caused by burns or crush injuries where plasma is lost or by severe dehydration
Fight or flight
When pressure receptors in the aorta and carotid artery sense decreased flow, they stimulate the release of epinephrine and norepinephrine into the bloodstream. This causes blood vessels to constrict, especially in the skin, kidneys and gastrointestinal tract. When blood vessels in the skin constrict, the skin becomes cool and pale. Sweat glands empty their contents, causing the sweaty skin so commonly seen in this situation. When blood vessels in the kidney constrict, the kidneys produce less urine, thereby preventing the loss of more fluid. Constriction of blood vessels in the GI tract causes the stomach to try to empty its contents leading to nausea and vomiting.
Neurogenic shock
result from the uncontrolled dilation of blood vessels from nerve paralysis caused by spinal cord injuries. Although there is no actual blood loss, the dilation of the blood vessels increases the circulatory systems capacity to the point where the available blood can no longer adequately fill it
Sepsis (also called blood poisoning) and anaphylactic reaction also results in vasodilation that may cause shock
Platinum 10 minutes
The goal for on scene time when caring for a trauma or shock patient has been stated as a maximum of 10 minutes.
Acidosis (lactic acid)
a condition that occurs when cells receive insufficient oxygen and generate acidic waste products that accumulate in the blood.
Layers of vessels starting from the outside
External elastic membrane Smooth muscle Internal elastic membrane Lumen Endothelium Valve- just veins
What’s narrowing of blood pressure
As the difference between the systolic and diastolic pressure decrease, it shows signs of shock
