Vol.4-Ch.5 "Burns" Flashcards
How does a thermal burn occur?
What 3 major factors determine the damaging effect of a hot substance? (thermal burn)
As a substance gets hotter its molecules move faster and collide faster, this creates heat and energy. When this head and energy gets close to skin it transfers that energy to the skin, denaturing proteins and cell membranes.
1) its temperature
2) concentration of heat it has (depends on density)
3) length of time in contact
(for #2 imagine steam at a certain temp hitting you VS grease hitting you at same temp)
What are the 3 zones of Jackson’s Theory of Thermal Wounds? Describe what is happening in each zone.
1) Zone of Coagulation - the closest to the heat source; cells membranes are rupturing, protein are denaturing, and blood is coagulating
2) Zone of Stasis - just outside zone of coagulation; is a less damaged area that is still inflamed and has decreased blood flow
3) Zone of Hyperemia - outside zone of stasis; this has limited inflammation and blood flow restriction, it mostly just accounts for erythema
If the zone of coagulation penetrates the _____ the burn is considered to be full thickness or 3rd degree
Dermis
At what % of the body being burned can you get large scale pathological effects on the body as a whole?
15-20%
What are the 4 phases of the bodies response to burns?
- Emergent Phase
- Fluid Shift Phase
- Hypermetabolic Phase
- Resolution Phase
What happens in the Emergent Phase of the bodies response to a burn?
First phase ; includes a pain response and the dumping of catecholamines in response to pain. The Pt will experience:
- tachycardia
- tachypnea
- mild hypertension
- mild anxiety
What happens in the Fluid Shift Phase of the bodies response to a burn?
Second phase ; this occurs in patients with burns 15-20% of the bodies surface and happens over up to 24 hours, but peaking at 6-8 hours. It is when the body begins releasing agents to initiate the inflammatory response which increases blood flow to capillaries near the burn and capillary permeability. This causes a large shift of fluids from the intravascular space to the extravascular space.
What occurs in the Hypermetabolic Phase and Resolution Phase of the bodies response to a burn?
Hypermetabolic Phase:
-third phase; can last days or week and is the bodies increase of demands for nutrients as the body begins to heal
Resolution Phase:
- fourth and last phase; scar tissue is formed and the Pt is rehabilitated and back to normal function
What is:
- voltage
- current (measured in?)
- resistance (measured in?)
Voltage - is the difference between two concentration of electricity (like difference in pressures)
Current - is the rate/amount of flow of electricity and is measured in AMPERES.
Resistance - is how resistance electricity is faces as it travels through a material and is measured in OHMS
What is Ohm’s Law?
V = IR
V = voltage I = current R = resistance
What is Joule’s Law? What does it calculate?
It calculates the heat produces by electrical current (power)
P = I^2 x R x t
P = power I = current R = resistance t = time during which it flows
How does skin and nervous tissue resistance electrical current?
Skin is highly resistant but the nervous system is not resistant as it is the bodies electrical impulse system
Where does the highest heat occur at in an electrical burn?
At the point of greatest resistance; i.e the skin with dry skin being more resistant than wet and thin skin
Are blood vessels and nerves more likely to be damaged in an electrical burn or bone and muscle?
Blood vessels and nerves because they offer less resistance
The _____ the area of contact the _____ the concentration of energy and therefore the _____ the injury.
The smaller the area of contact the greater the concentration of energy and therefore the greater the injury.
How do chemical burns do damage? What are the 2 most common causes?
They denature the biochemical make up of cell membranes (mostly proteins) and destroy the cells.
Acids and Alkalis are the most common causes.
(damage is usually LIMITED except with the most caustic substances b/c the injuries are not transmitted through the body, it must destroy what it is currently in contact with first before it can go deeper)
What is coagulation necrosis and what causes it?
Acid burns cause this and it is the formation of a thick, insoluble mass called a COAGULUM, and it helps to limit the depth of the acid burn but causes immediate pain.
What is liquefaction necrosis and what causes it?
Alkali burns cause this, it is the destruction of cell membranes and the release of intercellular and interstitial fluid, destroying tissue. It causes limited pain but does NOT form a coagulum, making these burns go much DEEPER THAN ACID burns.
It also progressively denatures proteins and collagen, dissolves fats, dehydrates tissues, and damages blood vessels.
Alkalis are commonly used in oven and drain cleaners, agricultural fertilizers and in industry.
How does radiation damage occur?
It does damage through IONIZATION, in which radioactive energy particles travel into a substance and change an internal atom
What 3 things happen to cells that are effected by ionization?
What human cells are most sensitive to radiation injury?
1) cell repairs damage
2) cell dies
3) cell produces more damaged cells (cancer)
Cells that reproduce quickly are most sensitive:
erythrocytes, leukocytes, platelets, cells in intestinal tract, and reproductive cells
What are the 4 types of ionizing radiation? Describe them.
1) Alpha Radiation : very weak; stopped by paper, clothing, or the epidermis; can only travel a few inches, though very large atomically (only dangerous if inhaled)
2) Beta Radiation : although smaller than alpha it can travel up to 6-10ft and penetrate clothing and first few millimeters of skin. It has potential for external/internal injury
3) Gamma Radiation : (x-rays) most powerful ionizing radiation, has no mass (is pure electromagnetic energy, or protons), has great penetrating power, requires thick concrete or lead protection
4) Neutron Radiation : great penetrating power b/c of small size and no charge, not found outside of nuclear reactors or bombs
What are the 2 mechanisms people get exposed to ionization through?
1) unshielded person in direct exposure to source
2) exposure through dust, debris, or fluids that contain small particles of radioactive material
What are the 3 main factors that may affect the damage done by radiation exposure?
1) Duration of exposure
2) Distance from the source
3) Shielding from the source
What tools are used to detect radiation and in what units do they measure?
A Geiger Counter or Dosimeter (for prolonged exposure) measuring in a rad or Gray (1 Gray = 100 rads)
