Burns Flashcards
What is the pathophysiology of burns?
Skin is capable of tolerating up to 40 degrees for brief periods of time. However, the magnitude of tissue damage logarithmically increases as the temperature increases. The process of thermal damage is related to the denaturation of the proteins in the skin as the chemical bonds are broken down by the heat energy.
Burns are usually classified as superficial, partial thickness or full thickness burns.
Superficial burns involve the epidermis and are red and painful. Partial thickness burns involve the epidermis and some of the underlying dermis. The skin can be blistered, glistening and very painful.
Full thickness burns appear white and leathery, or charred in severe cases. A full thickness burn has three zones of tissue injury. The central zone, the zone of coagulation, is where most of the damage is done and is necrotic and not capable of regeneration. The next zone is the zone of stasis. The tissue in this area is damaged but capable of repair if not deprived of oxygen or blood flow. This is the area where ice or very cold water may detrimentally affect the recovery of tissue by causing vasoconstriction. The outermost area is the zone of hyperaemia with minimal tissue damage, increased blood flow and erythema.
Although important in hospital the depth of burns is difficult to determine and doesn’t really effect pre-hospital treatment. Of more significance is the TBSA that is affected. If the burned is less than 20 % then a local response results if more than 20 % then a systemic response occurs as well, as the body becomes overwhelmed by the widespread inflammation and fluid loss. (PHTLS, 2011).
What is the epidemiology of burns?
In the UK, burn injuries are experienced by an estimated 250,000 people every year resulting in 175,000 visits to an emergency department annually and 13,000 admissions to hospital. During an average year, around 1000 people are admitted with serious burns requiring fluid resuscitation, of which half are under 16 years of age. The chance of surviving major burns has improved steadily over the last two decades but an average of 300 fatalities occur annually. However, the risk of death from major burns in those over 60 has remained constant, whereas, the survivability has improved in younger adults and children (National Burn Care Review Committee, 2001). The improvements in survivability are due to a better understanding of ‘burn shock’, advances in the use of fluid therapy, analgesia and antibiotics, better debridement techniques and the formation of specialist burns teams (Caroline, 2013). Serious burn injury accounts for 5.4% of all serious trauma (Kalson et al, 2011).
Burn injury most commonly occurs in the home (over 30 %) with the kitchen being the most likely location. The most common sources of injury are; cup of tea in children, petrol ignition in adults, bathing, kettle spills and central heating radiators in the elderly (National Burn Care Group, 2008).
What is the treatment for burns?
As always, a dynamic risk assessment is vital. An ambulance technician is of no use to a burns victim if they succumb to the effects of the fire, whether that be directly through thermal injury or indirectly through smoke inhalation. Inhalation of smoke is a life-threatening injury that is frequently more dangerous than the burn injury (Tredget, 1990). Toxic gases such as hydrogen cyanide and carbon monoxide can remain in areas with limited ventilation even after the fire has been extinguished.
A standard ABC assessment would take place with particular attention being paid to the airway. The nostrils and mouth would be checked for any sign of soot as this would be indicative of potentially life-threatening inhalation of smoke and toxins. The initial treatment of the burn injury would be to stop the burning process by removing any smouldering clothes or other items that may retain heat. If clothes adhere to the skin, cut away the excess material, leaving behind the attached fragments so as not to cause further damage to the skin. Next, you would irrigate the injury with copious amounts of room temperature water. This would be to done to remove heat from the injury and provide an analgesic effect. Cold water or ice is contraindicated because the resultant vasoconstriction would increase the likelihood of necrosis of tissue in the zone of stasis. This would outweigh the analgesic benefits the cold water and ice would provide. Prolonged cooling or cooling over a large area can cause hypothermia to develop so it is important to keep the patient warm. NB that hypothermia is part of the lethal triad of trauma (Sharpe et al, 2011).
Infection is a considerable hazard to the patient and so aseptic techniques are essential. Sterile non-adherent dressing and sheets of cling-fling can be applied to keep the injury cool and protected from infection. Do not apply the clink-film circumferentially due to the potential for tissue swelling and resulting tourniquet effect.
Consider the MOI as other significant injuries may exist in addition to the burn. Rapid transport to hospital with a pre-alert due to time critical nature of the injury and resultant complications. Consider the best position for the patient to minimise pain, consider elevating affect limbs to minimise fluid loss.
Paramedic may consider IV fluids to combat hypovolaemic shock and can administer morphine, a strong opioid analgesic which will help block pain receptors, unless contraindicated (JRCALC, 2013).
NB
Circumferential burns - escarotomies (PHTLS, 2011).
Trauma can be defined as a disease caused by physical injury. Major trauma is that which may cause death or severe disability (Brohi K et al 2009). As such a major burn is can be classed as trauma.
When does hypovolaemic shock occur with regards to burn?
When more than 20% TBSA is affected a systemic response will occur. Caroline 2013.
When blood volume is reduced by 15-25% due to serum being lost from the circulatory system. Cardiac output will fall because of low blood volume and hence low venous return.
Ross and Wilson. 2010
What complications are associated with burns?
Although burns usually affect the skin. If the burns are extensive enough, systemic reactions may occur that can be fatal or life-threatening.
These include:
Hypovolaemic shock - develops when 15% or more of the surface area is affected.
Hypothermia
Infection - can result in septicaemia.
Renal failure - kidney tubules cannot deal with amount of waste from haemolysed erythrocytes and damaged tissue.
Describe kee at all description of burn shock.
Kee et al 2009
Increased capillary permeability in area of burn injury due to inflammatory response -loss of plasma proteins and electrolytes-increase in interstitial fluid - massive oedema and decrease in intravascular volume-hypovolaemia-reduce venous return reduced cardiac output hypotension, tachycardia - burn shock!
How long does burn shock take to develop?
6-8 hours so look out for other causes of shock if patient appears shocked in the pre-hospital environment. Caroline 2013.
