burns Flashcards
Severe Burn Patient - A burn occurs when there is injury to body tissue caused by:
heat
chemicals
electrical current
radiation
The extent of the burn is influenced by:
temperature of the burning agent
duration of contact time
type of tissue injured
Types of Burns
A. Thermal Burns
Caused by flame, flash, scald, sunburn, or contact with hot objects.
Most common type of burn
chemical burn
B. Chemical Burns
Acids, alkalis & organic compounds. Eyes can be injured due to splashes. Can cause respiratory problems if inhaled.
Household cleaners, fertilisers, industrial cleaners, petrol, creosote, chlorine.
burns
C. Electrical Burns
Intense heat from an electrical current.
Direct damage to nerves & vessels can cause anoxia & death.
Electrical current that passes through vital organs will produce more life threatening consequences.
Severity of a burn is determined by:
the depth of the burn the extent of the burn (percentage of total body surface area) the location of the burn patient risk factors local response to burn injury
Depth of Burn
Burns are defined according to the depth of skin destruction. Partial thickness & full thickness.
- Partial thickness
Superficial partial thickness includes the epidermis e,g, sunburn
Deep partial thickness includes the dermis e.g. Flame, flash, scald, chemical, electric
- Full thickness
Includes fat, muscle, tendons, bones e.g. Flame, scald, chemical, electric
Extent of burn
Total body surface area needs to be worked out to determine the extent of the burn.
Two commonly used guides include:
- Lund-Browder chart
- Rule of nines
Lund-Browder chart is considered the most accurate. The rule of nines is considered easy to remember & effective to initial assessment.
Location of burn
Burns to face and neck, chest and back may inhibit respiratory function due to mechanical obstruction secondary to oedema or leathery, devitalised tissue (eschar). These injuries may also indicate inhalation & respiratory mucosal damage.
Burns to hands and feet, joints and eyes are concerning because they alter the persons ability to function (self-care). Vascular & nerve supply need to be maintained during healing.
Burns to ears & nose are susceptible to infection due to poor blood supply to the cartilage.
Burns to buttocks or perineum high risk for infection.
Circumferential (all the way round) burns to upper or lower extremities can compromise circulation. Nerve damage can cause neurological impairment. Patients may also develop compartment syndrome from damage to the muscles & susequent oedema & vascular problems.
Patient risk factors
Older adults heal slower & have more difficulty with rehabilitation.
Patients with pre-existing conditions (cardiovascular, respiratory or renal diseases) have poorer prognosis because of the extra demands placed on the body by the burn injury.
Patients with diabetes mellitus or peripheral vascular disease have poor healing and at risk for gangrene.
Physical debilitation from any chronic disease (alcoholism, drug abuse, malnutrition) leaves the patient physiologically less able to recover.
Other injuries sustained at the time of burn (fractures, head injury, trauma) also complicates recovery.
Local response to burn
Zone of coagulation—This occurs at the point of maximum damage. In this zone there is irreversible tissue loss due to coagulation of the constituent proteins.
Zone of stasis—The surrounding zone of stasis is characterised by decreased tissue perfusion. The tissue in this zone is potentially salvageable. The main aim of burns resuscitation is to increase tissue perfusion here and prevent any damage becoming irreversible. Additional insults—such as prolonged hypotension, infection, or oedema—can convert this zone into an area of complete tissue loss.
Zone of hyperaemia—In this outermost zone tissue perfusion is increased. The tissue here will invariably recover unless there is severe sepsis or prolonged hypoperfusion.
Phases of Burn Management
Fluid shift burns3 phases that correspond with the key priority?
Emergent phase (resuscitative) Acute phase (wound healing) Rehabilitation phase (restorative)
Pre-hospital phase
first on the scene, rescue services who provide emergency services (ambulance, fire rescue, police). A B C’s is the first priority and initial first aid. See p. 548 3rd edition text & p. 453 4th edition text for more information on pre-hospital care.
Emergent Phase
The period of time required to resolve the immediate, life-threatening problems. This phase lasts up to 72hrs from the time of burn.
Primary concerns during this time is onset of hypovolaemic shock and odema formation. The phase ends when fluid mobilisation and diuresis begin
Fluid & electrolyte shifts
The greatest threat to a patient with a major burn is hypovolaemic shock caused by massive shift of fluids out of the blood vessels as a result of increased capillary permeability. Can begin as early as 20 minutes from time of burn.
As the capillary walls become more permeable, water, sodium & later plasma proteins (albumin) move into interstitial spaces and other surrounding tissue.
The progressive loss of protein from the vascular space decreases the colloidal osmotic pressure which results in more fluid shifting out of the vascular space into the interstitial space.
Fluid also moves to places that normally have minimal or no fluid, e.g. blisters, exudate.
Other sources of fluid loss during this phase are losses by evaporation from large, denuded body surfaces and the respiratory system.
The overall result of the fluid shifts and lossess is intravascular volume depletion & hypovolaemic shock.
Circulatory status is also impaired because of haemolysis (breaking down) of red blood cells caused by the insult of the burn injury & release of factors at the time of burn.
Thrombosis in the capillaries of burned tissue also causes additional loss of circulating RBC’s. Blood becomes more viscous (thick & sticky) and haematocrit (a measure of packed red cell volume) increases .
Major shifts in sodium & potassium also occur during this phase. Sodium rapidly shifts to the interstitial spaces & remains until oedema ceases. Potassium shift develops initially because of injured cells and haemolysed RBC’s release potassium into the circulation.
Adequate fluid resuscitation is required.
Complications
Three major organ systems most susceptible to complications during the emergent phase of the burn injury are:
Cardiovascular
Respiratory
Urinary
