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Immediate Care of the Burned Patient
BURNS
Causes of hypokalaemia
Immediate Care of the Burned Patient
Low potassium intake (dietary deficiency, intravenous fluids) Gastrointestinal losses (vomiting, diarrhoea, villous adenoma, fistula, uterosigmoidostomy)
S M Jones P M Gilbert
Renal losses • Increased renal tubular fluid flow (diuretics, osmotic diuretics) • Mineralocorticoid excess — Hyperaldosteronism (primary or secondary) — Glucocorticoid excess (Cushing’s syndrome, ectopic ACTH production, steroid therapy) — Liquorice ingestion • Renal damage (renal tubular acidosis types I and II, some forms of leukaemia, drugs e.g. gentamicin, amphotericin B) • Metabolic alkalosis • Magnesium depletion
Definition: a burn is a coagulative destruction of the surface layers of the body caused by heat, chemicals or irradiation. Burns are a common injury. In the UK alone, there are approximately 600 deaths, 150,000 burn injuries and 12,000 hospital admissions. Domestic burns and scalds account for 6% of the casualties attending A&E departments and over half of these occur in young children. Good early management of burns is essential in the immediate resuscitation period, but burns are frequently mismanaged.
Pathophysiology Shift into the ICF • Drugs (insulin, β-adrenergic agonists) • Alkalosis
Rather confusingly, hypokalaemia also leads to progressively severe weakness of smooth and striated muscle, resulting in severe weakness, loss of tendon reflexes, paralytic ileus and even respiratory failure. Hypokalaemia can also trigger dysrhythmias (as well as ST segment depression, T wave inversion and U waves) in susceptible patients, particularly those on cardiac glycosides (digoxin). As with hyperkalaemia, symptomatic hypokalaemia is a medical emergency that needs prompt treatment with close supervision. Solutions containing more than 20 mmol/l of potassium should not be administered into a peripheral vein, or without appropriate cardiac monitoring, and should never be administered at greater than 40 mmol per hour outside an intensive care unit. Asymptomatic hypokalaemia can be treated by oral potassium supplementation, although slow-release preparations are associated with small bowel ulceration and should be avoided. u
Skin is important for many reasons. It protects against infection, it is a waterproof barrier, a sensory organ and aids in temperature control. It is also involved in secretion and excretion of substances such as water, salt, sebum and urea. Thus, any damage may have wide-ranging effects. Figure 1 shows the structures in skin. Tissue necrosis is directly related to the temperature of the burn-causing agent and contact duration. With heat burns, pain and rapid withdrawal from the burn agent are seen at temperatures of around 43.5 °C and tissue damage at temperatures above 48 °C. However, it must also be remembered that burns can be caused by chemicals and electricity, where the level of tissue damage will be affected by other factors. Immediately a burn is sustained, permeability of the capillaries is increased for approximately 48 hours, and is maximal at 8 hours. The capillaries leak water, electrolytes and albumin (proteins with a molecular weight < 350 kDa), causing oedema. Hypovolaemic shock may occur in larger burns where there is a generalized increase in capillary permeability. This plasma loss results in increased viscosity of the blood. Platelets and polymorphonuclear leucocytes adhere to damaged intima at the burn site leading to microthrombosis of fine peripheral capillaries. Haemoglobin is released into the blood from red blood cells (destroyed at the time of the burn or damaged on
FURTHER READING Park G R, Roe P G. Fluid Balance and Volume Resuscitation for Beginners. London: Greenwich Medical Media, 2000.
S M Jones is Acting Registrar at the Queen Victoria Hospital, East Grinstead, UK. She qualified from Oxford and United Medical and Dental Schools, London. She completed her basic surgical training at the Norfolk and Norwich University Hospital, Norwich.
8
P M Gilbert is a Consultant Plastic Surgeon and Director of the McIndoe Burn Centre at the Queen Victoria Hospital, East Grinstead, UK. He initially trained in dentistry but, after maxillo-facial surgery training, studied medicine and plastic surgery. His main interests are burns, facial deformity and vascular malformation.
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following day. A good test is to firmly rub the indistinct area; with erythema the skin remains intact.
Skin anatomy ����������
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Superficial burns The epidermis and papillae of dermis are involved, resulting in bright red or pink serum-filled blisters. The skin blanches on pressure and is pink, painful and sensitive. The epidermis often appears loose (unlike erythema) and blisters (Figure 2). Healing generally occurs within 7–10 days with minimal or no scarring.
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Partial-thickness burns Mid-dermal: in partial-thickness burns the epidermis is lost, along with varying degrees of dermis. The burn is ‘pink stained’ with small white speckled patches. This is caused by microthrombosis of vessels and the white patches are dermis. The burn blanches on pressure and is sensitive. If epithelial cells are present from hair follicles and sweat glands they will regenerate and spread, producing islands of dermal cells, i.e. healing is better on hairy skin. Healing generally occurs in 7–14 days depending on dermal destruction. Some mild pigmentation or scarring may result.
������������ ������ ����������� ������������� ������������� ������������������� 1
Deep-dermal burns: in deep dermal burns there is deeper dermal destruction. The burn appears white with little staining and does not blanche on pressure. It is insensitive and heals over a longer period of time (14–21 days), with scarring which may become hypertrophic (especially in children). Frequently, these burns require skin grafting for optimum healing.
passing through injured capillaries). This is lost in urine (haemoglobinuria) and can damage the kidneys. Burns increase metabolic rate, oxygen consumption, nitrogen loss and energy wastage through heat and water losses. Cortisol levels rise immediately, triggering protein catabolism, and in major burns both impaired insulin release and resistance can occur. This results in a massive catabolic drive (autocannibalism) through increases in catecholamines and glucagon, in which protein is broken down to provide the carbohydrate intermediaries essential for fat oxidation. This leads to a prolonged increase in oxygen consumption and heat production.
Full-thickness burns Full thickness burns result in total destruction of the dermis. The burn is leathery, white, insensate and does not blanch on pressure. Thrombosed vessels may be visible (Figure 3). Healing occurs from around the edges of the surrounding epithelium but is very slow with much scarring and contracture. Thus, all but very small full-thickness burns (i.e. less than 3 cm diameter) are generally best treated with a skin graft.
Classification Burn wounds can repair themselves if there are still viable epithelial cells in the base of the wound, e.g. hair follicles, sweat glands and sebaceous glands. Thus, the depth of the burn will determine healing potential and so classification is clinically useful.
Different types of burn Scalds Usually due to hot tea and coffee, cooking pans and hot baths. Depth is usually superficial or mid-dermal, but in infants and
Understanding the depth of burns The ability of the skin to repair itself depends on the depth of burn, which, as stated above, depends on the length of exposure and temperature of the burning agent. Burns can be divided into: • superficial burns • partial thickness burns (mid-dermal) • partial thickness burns (deep-dermal) • full-thickness burns. Erythema It is important not to confuse erythema with burn. This can lead to overestimation of the burn percentage, and inappropriate management. Erythema appears red and blanches on pressure. There are no blisters and usually skin has recovered by the
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2 Superficial burns.
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myoglobinuria can be expected in high-tension electrical burns or any very deep burn. Treatment should be directed at maintaining a high urinary output with a pH of ≈6.5 to try to prevent renal damage. Chemical burns The general rule is to wash off with copious quantities of running water. Acids: sulphuric and hydrochloric acid burns occur from industrial usage, car batteries and occasionally assaults. Hydrofluoric acid (HFl) is used for etching glass and in the electronics industry, by window cleaners, and in the pottery and china industries. Burns may penetrate to the bone or until the fluorine is neutralized by the tissues. Again, wash the acid off with water immediately. Calcium gluconate gel is often recommended for the treatment of HFl burns, but it is not as effective as iced water. Alkalis: these may be caused by a variety of common products. Sodium hydroxide (caustic soda) is an ingredient in drain and oven cleaners, and is also used in furniture restoration. Cement is a cause of common alkali burns. They often go unnoticed when cement gets inside shoes or boots, until they are removed, often resulting in deep-dermal and full-thickness injuries. Other chemical burns are rare. If the burn is caused by a proprietary agent, the manufacturer or poisons centre can be contacted for help.
3 Full-thickness burn. Note visible thrombosed vessels.
the elderly where the skin can be thin, deep-dermal and fullthickness injuries are seen. Hot fat has a higher temperature than boiling water and, because of its viscosity, contact time may be greater; therefore deep-dermal and full-thickness injuries often result. Flame burns Often associated with the use of petrol and other accelerants, but cigarettes are the main cause. Flash or flame burns may be superficial but if clothing catches alight then deep-dermal and full-thickness injuries occur.
First aid 1 Remove from the burn-causing agent • If the victim is on fire smother with a blanket • With scald injuries remove any hot water-soaked clothing • For patients with electrical burns remember to turn off the electrical source before administering first aid 2 Check airway, level of consciousness and circulation 3 Apply cold water (or watergel if available) to the burn for about 5 minutes. This may reduce the depth of burn and is soothing. However, beware not to cool the patient too much, which may result in hypothermia 4 Cover burn with clingfilm, and keep the victim warm with towels and blankets 5 Transfer to the nearest accident and emergency department.
Contact burns Most common are injuries sustained when touching the hot plate on a cooker or iron, or when there has been prolonged contact with a hot radiator. These often result in deep-dermal and fullthickness injuries. Electrical burns Electrical flash burns: most burns that occur from an electrical short are not conductive electrical burns; more commonly they are flash burns. The flash from an electric arc has a temperature of about 4000 °C and lasts a tenth of a second. No electricity is passed through the body. Flash burns are generally found on the face and are superficial. Corneal burns are rare due to the blink reflex. Low-tension burns: household electrical burns are usually caused by faulty wiring or by undertaking repairs on electrical appliances when the current has not been switched off. Burns are usually small and limited to where the live wire contacted, and invariably full-thickness. High-tension burns: power lines and electrical sub-stations carry voltages as high as 32,000 V in the UK. Electrical conduction burns usually have an entry and exit wound which are usually fairly separated. Electric current passes along planes of least resistance, i.e. blood vessels, fascia and muscle. Therefore, the amount of tissue destroyed is far greater than is apparent from the comparatively small skin burn. First aid: ensure the electricity is off. Remove the patient from the electrical source and apply cold water soaks. Effects on the heart are fibrillation, arrhythmia or ischaemia, diagnosed with ECG and cardiac enzymes. Myonecrosis with
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Management in accident and emergency History of injury Immediate details include the time of injury, the agent involved and the first aid that was given. Consider the possibility of non-accidental injury. Relevant medical history Discover if the burns were a result of medical disease or drugs, e.g. diabetes, epileptic fit, alcohol abuse. Discover if the patient has any existing diseases that may affect healing, e.g. diabetes or conditions requiring steroids or immunosuppressives. Examination ATLS survey: there may be injuries that are more important than the burn.
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Area of burn: calculate the percentage of body surface area (BSA). Wallace’s Rule of Nines: head and neck 9%, each arm 9%, anterior trunk 2 × 9%, posterior trunk 2 × 9%, each leg 2 × 9%, leaving 1% for perineum. Area of patient’s hand: this is approximately 1% of BSA. Lund and Browder charts: these should be available in all A&E departments, including the modifications necessary to calculate burn percentages in children and infants whose body proportions are different from the adult. These charts must be filled in accurately and the percentage burn estimated using the instructions on the charts (Figure 4). Depth of burn: this is only important in A&E if the depth and distribution of the burn is causing ischaemia of the extremities or causing difficulties with chest expansion and respiration.
On the chest, escharotomies should be performed bilaterally in the anterior axillary lines. If done adequately, obvious release of the underlying soft tissues will be noted. If chest excursion is still not adequate, then the incisions can be joined with a chevron-like incision over the costal margin. On the extremities, pulses can be assessed using Doppler or by pinprick to the fingers or toes. Slow or absent bleeding indicates diminished or absent arterial inflow. Rapid, dark bleeding indicates partial or complete venous occlusion. In either case, immediate escharotomies should be performed, prior to transfer to the Burns Unit. Extremity escharotomies are performed in the mid-lateral lines of the limb and should extend through the entire length and depth of the eschar (Figure 5). Anaesthesia is sometimes required for this but generally full thickness burns are insensitive. Remember that bleeding can be vigorous and best done in a theatre environment.
Escharotomy Deep circumferential burns produce an unyielding band that restricts capillary perfusion. Clinical evaluation includes monitoring of pulse, circulation and sensation distally. Quantitative monitoring of tissue pressures may be done with a wick catheter. Capillary filling pressure is ≈25 mmHg. If the pressure is 30 mmHg or more on two separate occasions then escharotomy is indicated. Clinically, however, if the limb feels tight then escharotomy should also be considered (Figure 5). Circumferential eschar of the chest can result in respiratory compromise. In the limbs, it can cause compartment syndromes and/or distal ischaemia and necrosis.
Resuscitation Because of the fluid loss associated with burn injuries, intravenous fluid resuscitation is required where burns in children exceed 10% BSA, and in adults 15% BSA. Crystalloid resuscitation, using the Parkland formula as a guide, works well in practice. Always discuss resuscitation cases with your regional burns centre. Monitoring is necessary to assess the effectiveness of resuscitation. The minimum level of monitoring is accurate estimation of urine output, catheterization is therefore required. Parkland Formula Volume given = 4 ml × %TBSA × weight (kg)
Escharotomy technique: escharotomy can be done at the bedside. Bleeding may be brisk and blood should be available for transfusion. Local anaesthesia is usually unnecessary: eschar is insensate. However, if it is important that the whole compartment is released anaethesia may be required.
Give half in the first 8 hours, then give the rest over the next 16 hours. Therefore, you start with: 0.25 ml × %TBSA × weight (kg) = mls/hour Resuscitate with Hartman’s solution. Aim to achieve urine output greater than 0.5 ml/kg/hr, pulse rate lower than 120 bt/min, and a lucid, calm patient. Resuscitation may also be achieved using plasma, calculated by the Muir and Barclay formula:
4 Lund and Browder chart.
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5 Escharotomy of the lower limb.
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Surgery: a surgical approach can be adopted any time from admission of the patient to many weeks post burn where conservative treatment has failed. Deep-dermal burns constitute a difficult group. In many cases, there are not enough viable epithelial remnants in the skin to allow healing. Hairy areas such as the scalp may heal, as can the back where the dermis is thick. Where the skin is thin and non-hairy, grafting will usually be necessary and so there is no point pursuing conservative treatment beyond 10 days. Full-thickness burns should always be excised. If the area of burn is only a small percentage of BSA then delaying surgery, particularly if there are other health problems, can be justified. The use of topical antibacterial creams will keep the wound clean. In massive full thickness burns, excision of the burnt tissue should be undertaken in stages as soon after the injury as practicable, certainly within the first 3–4 days. If this is not done then bacterial colonization of the burnt tissue takes place, resulting in bacteraemia, septicaemia and sometimes death. Once the burnt tissue has been excised, skin cover is required to prevent gross fluid loss and infection. Skin cover may be achieved with autologous skin grafts (split skin or full-thickness), with or without meshing. Cadaver skin and artificial dermal substitutes may also be used, and each has its advantages and disadvantages. Sterne and Fatah (page 134) cover the topic in more depth.
Weight (kg) × burn% = mls/4 hours 2 for first 12 hours
Respiratory burns Suspect smoke inhalation in the following circumstances: • explosions • flame burns, particularly in enclosed space burns of the face • soot in mouth and nostrils • increasing hoarseness or stridor. Intubation may be necessary, and if it is likely from the history that the burn has caused respiratory injury, this must be done prior to transfer to a burns centre. Blood carboxyhaemoglobin levels may be a useful indicator of a significant inhalation injury to the lungs. Tetanus prophylaxis This should be done if necessary. Antibiotics should not be required at this stage. Dressings Superficial burns of less than 5% can be treated in A&E on an out-patient basis if the area can be easily dressed. However, dressings can be very time consuming in a busy A&E so referral to a burns centre may be advisable. Loose, blistered skin should be removed and the wound dressed with Vaseline gauze, e.g. Jelonet or Duoderm. Burns other than minor ones should be assessed in a burns centre.
Survival following burns This depends on the area and depth of burn, respiratory injury, age of patient and pre-existing medical condition. If the age of the patient plus the area of deep-dermal or fullthickness burn exceeds 100 then prognosis is poor. Bull and Fisher have published survival tables but major burn centres do better than their predicted levels.
Toxic shock syndrome This may occur even after a minor injury, and small children are especially vulnerable, so parents must be warned of the symptoms. Onset is sudden, with vomiting, diarrhoea, a temperature higher than 40 °C, diffuse macular rash which later desquamates, tachypnoea, oliguria, irritability, convulsions and coma. Typically, it develops on the third or fourth day following injury. The signs are usually associated with a fall in haemoglobin and white cell count. Toxic shock syndrome is thought to be due to a toxin produced by Staphylococcus aureus phage type 29/52. Treatment must be prompt, with control of temperature, reduction of any cerebral oedema, and the administration of whole blood, immunoglobulins and antibiotics.
Long-term problems Once the burn has been fully epithelialized there are still major problems, such as repeated wound breakdown, scarring, contracture, and cosmetic and psychological problems. These are beyond the immediate care phase and scope of this article; however, the rehabilitation of the patient back into society, so that he or she can lead an independent and useful life, must not be forgotten. u
Management in the burns centre Reassessment of injury Includes the area and depth of burn, respiratory status, other injuries and adequacy of resuscitation. Burn wound management Conservative: if the wound appears to be superficial or mid-dermal (i.e. may heal without grafting), dressings with silver sulphadiazine cream (flamazine) are indicated. Theoretically, these should be changed daily but in practice can be left for 2–3 days. Laser Doppler scanning has been shown to be helpful in estimating burn depth (best done on the third day post-injury). Many new and expansive dressings are available for superficial or mid-dermal burns, but their true place is as yet undecided.
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FURTHER READING Cason J S. Treatment of Burns. London: Chapman and Hall Ltd, 1981. Press B. Thermal, Electrical and Chemical Injuries. In: Grabb and Smith’s Plastic Surgery. Aston S J, Beasley R W, Thorne C H M, eds. Baltimore: Lippincott Williams and Wilkins, 1997. Settle J. Burns: The First Five Days. Essex: Smith and Nephew, 1986.
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Causes of hypokalaemia
Immediate Care of the Burned Patient
Low potassium intake (dietary deficiency, intravenous fluids) Gastrointestinal losses (vomiting, diarrhoea, villous adenoma, fistula, uterosigmoidostomy)
S M Jones P M Gilbert
Renal losses • Increased renal tubular fluid flow (diuretics, osmotic diuretics) • Mineralocorticoid excess — Hyperaldosteronism (primary or secondary) — Glucocorticoid excess (Cushing’s syndrome, ectopic ACTH production, steroid therapy) — Liquorice ingestion • Renal damage (renal tubular acidosis types I and II, some forms of leukaemia, drugs e.g. gentamicin, amphotericin B) • Metabolic alkalosis • Magnesium depletion
Definition: a burn is a coagulative destruction of the surface layers of the body caused by heat, chemicals or irradiation. Burns are a common injury. In the UK alone, there are approximately 600 deaths, 150,000 burn injuries and 12,000 hospital admissions. Domestic burns and scalds account for 6% of the casualties attending A&E departments and over half of these occur in young children. Good early management of burns is essential in the immediate resuscitation period, but burns are frequently mismanaged.
Pathophysiology Shift into the ICF • Drugs (insulin, β-adrenergic agonists) • Alkalosis
Rather confusingly, hypokalaemia also leads to progressively severe weakness of smooth and striated muscle, resulting in severe weakness, loss of tendon reflexes, paralytic ileus and even respiratory failure. Hypokalaemia can also trigger dysrhythmias (as well as ST segment depression, T wave inversion and U waves) in susceptible patients, particularly those on cardiac glycosides (digoxin). As with hyperkalaemia, symptomatic hypokalaemia is a medical emergency that needs prompt treatment with close supervision. Solutions containing more than 20 mmol/l of potassium should not be administered into a peripheral vein, or without appropriate cardiac monitoring, and should never be administered at greater than 40 mmol per hour outside an intensive care unit. Asymptomatic hypokalaemia can be treated by oral potassium supplementation, although slow-release preparations are associated with small bowel ulceration and should be avoided. u
Skin is important for many reasons. It protects against infection, it is a waterproof barrier, a sensory organ and aids in temperature control. It is also involved in secretion and excretion of substances such as water, salt, sebum and urea. Thus, any damage may have wide-ranging effects. Figure 1 shows the structures in skin. Tissue necrosis is directly related to the temperature of the burn-causing agent and contact duration. With heat burns, pain and rapid withdrawal from the burn agent are seen at temperatures of around 43.5 °C and tissue damage at temperatures above 48 °C. However, it must also be remembered that burns can be caused by chemicals and electricity, where the level of tissue damage will be affected by other factors. Immediately a burn is sustained, permeability of the capillaries is increased for approximately 48 hours, and is maximal at 8 hours. The capillaries leak water, electrolytes and albumin (proteins with a molecular weight < 350 kDa), causing oedema. Hypovolaemic shock may occur in larger burns where there is a generalized increase in capillary permeability. This plasma loss results in increased viscosity of the blood. Platelets and polymorphonuclear leucocytes adhere to damaged intima at the burn site leading to microthrombosis of fine peripheral capillaries. Haemoglobin is released into the blood from red blood cells (destroyed at the time of the burn or damaged on
FURTHER READING Park G R, Roe P G. Fluid Balance and Volume Resuscitation for Beginners. London: Greenwich Medical Media, 2000.
S M Jones is Acting Registrar at the Queen Victoria Hospital, East Grinstead, UK. She qualified from Oxford and United Medical and Dental Schools, London. She completed her basic surgical training at the Norfolk and Norwich University Hospital, Norwich.
8
P M Gilbert is a Consultant Plastic Surgeon and Director of the McIndoe Burn Centre at the Queen Victoria Hospital, East Grinstead, UK. He initially trained in dentistry but, after maxillo-facial surgery training, studied medicine and plastic surgery. His main interests are burns, facial deformity and vascular malformation.
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following day. A good test is to firmly rub the indistinct area; with erythema the skin remains intact.
Skin anatomy ����������
���������� �����
����
Superficial burns The epidermis and papillae of dermis are involved, resulting in bright red or pink serum-filled blisters. The skin blanches on pressure and is pink, painful and sensitive. The epidermis often appears loose (unlike erythema) and blisters (Figure 2). Healing generally occurs within 7–10 days with minimal or no scarring.
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Partial-thickness burns Mid-dermal: in partial-thickness burns the epidermis is lost, along with varying degrees of dermis. The burn is ‘pink stained’ with small white speckled patches. This is caused by microthrombosis of vessels and the white patches are dermis. The burn blanches on pressure and is sensitive. If epithelial cells are present from hair follicles and sweat glands they will regenerate and spread, producing islands of dermal cells, i.e. healing is better on hairy skin. Healing generally occurs in 7–14 days depending on dermal destruction. Some mild pigmentation or scarring may result.
������������ ������ ����������� ������������� ������������� ������������������� 1
Deep-dermal burns: in deep dermal burns there is deeper dermal destruction. The burn appears white with little staining and does not blanche on pressure. It is insensitive and heals over a longer period of time (14–21 days), with scarring which may become hypertrophic (especially in children). Frequently, these burns require skin grafting for optimum healing.
passing through injured capillaries). This is lost in urine (haemoglobinuria) and can damage the kidneys. Burns increase metabolic rate, oxygen consumption, nitrogen loss and energy wastage through heat and water losses. Cortisol levels rise immediately, triggering protein catabolism, and in major burns both impaired insulin release and resistance can occur. This results in a massive catabolic drive (autocannibalism) through increases in catecholamines and glucagon, in which protein is broken down to provide the carbohydrate intermediaries essential for fat oxidation. This leads to a prolonged increase in oxygen consumption and heat production.
Full-thickness burns Full thickness burns result in total destruction of the dermis. The burn is leathery, white, insensate and does not blanch on pressure. Thrombosed vessels may be visible (Figure 3). Healing occurs from around the edges of the surrounding epithelium but is very slow with much scarring and contracture. Thus, all but very small full-thickness burns (i.e. less than 3 cm diameter) are generally best treated with a skin graft.
Classification Burn wounds can repair themselves if there are still viable epithelial cells in the base of the wound, e.g. hair follicles, sweat glands and sebaceous glands. Thus, the depth of the burn will determine healing potential and so classification is clinically useful.
Different types of burn Scalds Usually due to hot tea and coffee, cooking pans and hot baths. Depth is usually superficial or mid-dermal, but in infants and
Understanding the depth of burns The ability of the skin to repair itself depends on the depth of burn, which, as stated above, depends on the length of exposure and temperature of the burning agent. Burns can be divided into: • superficial burns • partial thickness burns (mid-dermal) • partial thickness burns (deep-dermal) • full-thickness burns. Erythema It is important not to confuse erythema with burn. This can lead to overestimation of the burn percentage, and inappropriate management. Erythema appears red and blanches on pressure. There are no blisters and usually skin has recovered by the
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2 Superficial burns.
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myoglobinuria can be expected in high-tension electrical burns or any very deep burn. Treatment should be directed at maintaining a high urinary output with a pH of ≈6.5 to try to prevent renal damage. Chemical burns The general rule is to wash off with copious quantities of running water. Acids: sulphuric and hydrochloric acid burns occur from industrial usage, car batteries and occasionally assaults. Hydrofluoric acid (HFl) is used for etching glass and in the electronics industry, by window cleaners, and in the pottery and china industries. Burns may penetrate to the bone or until the fluorine is neutralized by the tissues. Again, wash the acid off with water immediately. Calcium gluconate gel is often recommended for the treatment of HFl burns, but it is not as effective as iced water. Alkalis: these may be caused by a variety of common products. Sodium hydroxide (caustic soda) is an ingredient in drain and oven cleaners, and is also used in furniture restoration. Cement is a cause of common alkali burns. They often go unnoticed when cement gets inside shoes or boots, until they are removed, often resulting in deep-dermal and full-thickness injuries. Other chemical burns are rare. If the burn is caused by a proprietary agent, the manufacturer or poisons centre can be contacted for help.
3 Full-thickness burn. Note visible thrombosed vessels.
the elderly where the skin can be thin, deep-dermal and fullthickness injuries are seen. Hot fat has a higher temperature than boiling water and, because of its viscosity, contact time may be greater; therefore deep-dermal and full-thickness injuries often result. Flame burns Often associated with the use of petrol and other accelerants, but cigarettes are the main cause. Flash or flame burns may be superficial but if clothing catches alight then deep-dermal and full-thickness injuries occur.
First aid 1 Remove from the burn-causing agent • If the victim is on fire smother with a blanket • With scald injuries remove any hot water-soaked clothing • For patients with electrical burns remember to turn off the electrical source before administering first aid 2 Check airway, level of consciousness and circulation 3 Apply cold water (or watergel if available) to the burn for about 5 minutes. This may reduce the depth of burn and is soothing. However, beware not to cool the patient too much, which may result in hypothermia 4 Cover burn with clingfilm, and keep the victim warm with towels and blankets 5 Transfer to the nearest accident and emergency department.
Contact burns Most common are injuries sustained when touching the hot plate on a cooker or iron, or when there has been prolonged contact with a hot radiator. These often result in deep-dermal and fullthickness injuries. Electrical burns Electrical flash burns: most burns that occur from an electrical short are not conductive electrical burns; more commonly they are flash burns. The flash from an electric arc has a temperature of about 4000 °C and lasts a tenth of a second. No electricity is passed through the body. Flash burns are generally found on the face and are superficial. Corneal burns are rare due to the blink reflex. Low-tension burns: household electrical burns are usually caused by faulty wiring or by undertaking repairs on electrical appliances when the current has not been switched off. Burns are usually small and limited to where the live wire contacted, and invariably full-thickness. High-tension burns: power lines and electrical sub-stations carry voltages as high as 32,000 V in the UK. Electrical conduction burns usually have an entry and exit wound which are usually fairly separated. Electric current passes along planes of least resistance, i.e. blood vessels, fascia and muscle. Therefore, the amount of tissue destroyed is far greater than is apparent from the comparatively small skin burn. First aid: ensure the electricity is off. Remove the patient from the electrical source and apply cold water soaks. Effects on the heart are fibrillation, arrhythmia or ischaemia, diagnosed with ECG and cardiac enzymes. Myonecrosis with
SURGERY
Management in accident and emergency History of injury Immediate details include the time of injury, the agent involved and the first aid that was given. Consider the possibility of non-accidental injury. Relevant medical history Discover if the burns were a result of medical disease or drugs, e.g. diabetes, epileptic fit, alcohol abuse. Discover if the patient has any existing diseases that may affect healing, e.g. diabetes or conditions requiring steroids or immunosuppressives. Examination ATLS survey: there may be injuries that are more important than the burn.
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Area of burn: calculate the percentage of body surface area (BSA). Wallace’s Rule of Nines: head and neck 9%, each arm 9%, anterior trunk 2 × 9%, posterior trunk 2 × 9%, each leg 2 × 9%, leaving 1% for perineum. Area of patient’s hand: this is approximately 1% of BSA. Lund and Browder charts: these should be available in all A&E departments, including the modifications necessary to calculate burn percentages in children and infants whose body proportions are different from the adult. These charts must be filled in accurately and the percentage burn estimated using the instructions on the charts (Figure 4). Depth of burn: this is only important in A&E if the depth and distribution of the burn is causing ischaemia of the extremities or causing difficulties with chest expansion and respiration.
On the chest, escharotomies should be performed bilaterally in the anterior axillary lines. If done adequately, obvious release of the underlying soft tissues will be noted. If chest excursion is still not adequate, then the incisions can be joined with a chevron-like incision over the costal margin. On the extremities, pulses can be assessed using Doppler or by pinprick to the fingers or toes. Slow or absent bleeding indicates diminished or absent arterial inflow. Rapid, dark bleeding indicates partial or complete venous occlusion. In either case, immediate escharotomies should be performed, prior to transfer to the Burns Unit. Extremity escharotomies are performed in the mid-lateral lines of the limb and should extend through the entire length and depth of the eschar (Figure 5). Anaesthesia is sometimes required for this but generally full thickness burns are insensitive. Remember that bleeding can be vigorous and best done in a theatre environment.
Escharotomy Deep circumferential burns produce an unyielding band that restricts capillary perfusion. Clinical evaluation includes monitoring of pulse, circulation and sensation distally. Quantitative monitoring of tissue pressures may be done with a wick catheter. Capillary filling pressure is ≈25 mmHg. If the pressure is 30 mmHg or more on two separate occasions then escharotomy is indicated. Clinically, however, if the limb feels tight then escharotomy should also be considered (Figure 5). Circumferential eschar of the chest can result in respiratory compromise. In the limbs, it can cause compartment syndromes and/or distal ischaemia and necrosis.
Resuscitation Because of the fluid loss associated with burn injuries, intravenous fluid resuscitation is required where burns in children exceed 10% BSA, and in adults 15% BSA. Crystalloid resuscitation, using the Parkland formula as a guide, works well in practice. Always discuss resuscitation cases with your regional burns centre. Monitoring is necessary to assess the effectiveness of resuscitation. The minimum level of monitoring is accurate estimation of urine output, catheterization is therefore required. Parkland Formula Volume given = 4 ml × %TBSA × weight (kg)
Escharotomy technique: escharotomy can be done at the bedside. Bleeding may be brisk and blood should be available for transfusion. Local anaesthesia is usually unnecessary: eschar is insensate. However, if it is important that the whole compartment is released anaethesia may be required.
Give half in the first 8 hours, then give the rest over the next 16 hours. Therefore, you start with: 0.25 ml × %TBSA × weight (kg) = mls/hour Resuscitate with Hartman’s solution. Aim to achieve urine output greater than 0.5 ml/kg/hr, pulse rate lower than 120 bt/min, and a lucid, calm patient. Resuscitation may also be achieved using plasma, calculated by the Muir and Barclay formula:
4 Lund and Browder chart.
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5 Escharotomy of the lower limb.
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BURNS
Surgery: a surgical approach can be adopted any time from admission of the patient to many weeks post burn where conservative treatment has failed. Deep-dermal burns constitute a difficult group. In many cases, there are not enough viable epithelial remnants in the skin to allow healing. Hairy areas such as the scalp may heal, as can the back where the dermis is thick. Where the skin is thin and non-hairy, grafting will usually be necessary and so there is no point pursuing conservative treatment beyond 10 days. Full-thickness burns should always be excised. If the area of burn is only a small percentage of BSA then delaying surgery, particularly if there are other health problems, can be justified. The use of topical antibacterial creams will keep the wound clean. In massive full thickness burns, excision of the burnt tissue should be undertaken in stages as soon after the injury as practicable, certainly within the first 3–4 days. If this is not done then bacterial colonization of the burnt tissue takes place, resulting in bacteraemia, septicaemia and sometimes death. Once the burnt tissue has been excised, skin cover is required to prevent gross fluid loss and infection. Skin cover may be achieved with autologous skin grafts (split skin or full-thickness), with or without meshing. Cadaver skin and artificial dermal substitutes may also be used, and each has its advantages and disadvantages. Sterne and Fatah (page 134) cover the topic in more depth.
Weight (kg) × burn% = mls/4 hours 2 for first 12 hours
Respiratory burns Suspect smoke inhalation in the following circumstances: • explosions • flame burns, particularly in enclosed space burns of the face • soot in mouth and nostrils • increasing hoarseness or stridor. Intubation may be necessary, and if it is likely from the history that the burn has caused respiratory injury, this must be done prior to transfer to a burns centre. Blood carboxyhaemoglobin levels may be a useful indicator of a significant inhalation injury to the lungs. Tetanus prophylaxis This should be done if necessary. Antibiotics should not be required at this stage. Dressings Superficial burns of less than 5% can be treated in A&E on an out-patient basis if the area can be easily dressed. However, dressings can be very time consuming in a busy A&E so referral to a burns centre may be advisable. Loose, blistered skin should be removed and the wound dressed with Vaseline gauze, e.g. Jelonet or Duoderm. Burns other than minor ones should be assessed in a burns centre.
Survival following burns This depends on the area and depth of burn, respiratory injury, age of patient and pre-existing medical condition. If the age of the patient plus the area of deep-dermal or fullthickness burn exceeds 100 then prognosis is poor. Bull and Fisher have published survival tables but major burn centres do better than their predicted levels.
Toxic shock syndrome This may occur even after a minor injury, and small children are especially vulnerable, so parents must be warned of the symptoms. Onset is sudden, with vomiting, diarrhoea, a temperature higher than 40 °C, diffuse macular rash which later desquamates, tachypnoea, oliguria, irritability, convulsions and coma. Typically, it develops on the third or fourth day following injury. The signs are usually associated with a fall in haemoglobin and white cell count. Toxic shock syndrome is thought to be due to a toxin produced by Staphylococcus aureus phage type 29/52. Treatment must be prompt, with control of temperature, reduction of any cerebral oedema, and the administration of whole blood, immunoglobulins and antibiotics.
Long-term problems Once the burn has been fully epithelialized there are still major problems, such as repeated wound breakdown, scarring, contracture, and cosmetic and psychological problems. These are beyond the immediate care phase and scope of this article; however, the rehabilitation of the patient back into society, so that he or she can lead an independent and useful life, must not be forgotten. u
Management in the burns centre Reassessment of injury Includes the area and depth of burn, respiratory status, other injuries and adequacy of resuscitation. Burn wound management Conservative: if the wound appears to be superficial or mid-dermal (i.e. may heal without grafting), dressings with silver sulphadiazine cream (flamazine) are indicated. Theoretically, these should be changed daily but in practice can be left for 2–3 days. Laser Doppler scanning has been shown to be helpful in estimating burn depth (best done on the third day post-injury). Many new and expansive dressings are available for superficial or mid-dermal burns, but their true place is as yet undecided.
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FURTHER READING Cason J S. Treatment of Burns. London: Chapman and Hall Ltd, 1981. Press B. Thermal, Electrical and Chemical Injuries. In: Grabb and Smith’s Plastic Surgery. Aston S J, Beasley R W, Thorne C H M, eds. Baltimore: Lippincott Williams and Wilkins, 1997. Settle J. Burns: The First Five Days. Essex: Smith and Nephew, 1986.
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