% vol = 14 number = 4 nextlink = 168 titolo = "ON BURN DISEASE" volromano = "XIV" data_pubblicazione = "December 2001" header titolo %>
SUMMARY.More than 9000 cases of burn injury are treated in the Federal Republic of Germany every year - and effective therapy needs extensive knowledge of "burn diseases" and their particular potential of danger. The development of thermal damage within the organism is described in detail, as also disturbances of vital organic systems (brain, kidney, liver, etc.). The determination of burn dimension is related to knowledge of certain rules. These are very important for establishing appropriate therapy, which is fundamental especially in first-aid treatment. This phase affects the patient’s future outcome. After extensive first aid and secondary in-patient treatment, surviving persons with serious burns need specialized care for their rehabilitation.
Burn injuries - not just a local occurrence but a "burn disease"
More than 9000 cases of burn injury are treated in the Federal Republic of Germany every year. Minor burns are no problem for either the physician or the patient, whereas a burned body surface area (BSA) of only 10% in children and 20% in adults presents a drastic and often extremely crucial clinical picture, as there are dramatic links between local skin injuries and the overall damage caused by the external heat effect in the organism. Prognosis in burn diseases depends on the extent and depth of the burned BSA. Infants and elderly patients are particularly at risk. Nearly 1000 of the 9000 annual patients subsequently die, and it must be made clear and frequently repeated to first-aid physicians who work at the scene of burn accidents and to those involved in after-treatment in hospitals how extremely important it is to possess adequate basic knowledge.
The skin and its complex functions should be well known. As the highly destructive action of heat has very special effects on the whole organism - and also on the psyche, because of the extensive mutilations caused - a complex and always new plan of therapy must be followed.
The skin is highly sensitive to the effect of heat and presents damage to cell enzymes if exposed to a prolonged temperature of only 40 °C. Even the use of an electric pad may lead to damage because of the gradual rise in temperature. Burns caused by the direct effect of fire are more impressive, and an explosion can also cause attendant injuries. If the flame reaches the face, thermal damage may be caused to the nasal part of the pharynx and the respiratory tract.
Hot water and fumes cause scalds, in which case the damage is local and restricted if simply caused by spilling but may be fatal if the result of total immersion. Touching hot metal may cause contact burns resulting in far-reaching damage, especially if there is additional pressure. Injuries by chemical burns and colliquation or released heat may cause damage equal to that caused by real burns. Electricity can cause very severe burns and even charring, since vessels, nerves, and the muscular system are especially vulnerable owing to their high conductivity.
A short period of action of the injuring source results in superficial burns, while longer periods lead to deep burns, with charring and the melting of subcutaneous tissue. The circumstances of the burn do not however affect either the appearance or therapeutic procedures.
Burn injuries cause a disease that severely affects the whole organism. The problems of prognosis and treatment depend on the extent and depth of the wounds, as also on the localization of the burn. Also crucial are the age of the patient and any attending diseases. Decisive procedures have to be initiated directly at the scene of the accident - and this first aid affects the course of further treatment.
The definition of burn extent follows the "Rule of Nine", according to Wallace, but with essential differences for different age groups (Fig. 1).<% immagine "Fig. 1","gr0000001.jpg","'Rule of nine' in adults and in chilfren of different age groups in relation to percentage area of burned body surface.",230 %>
For the definition of burns a rough classification of burn degree is used, as follows:
The localization of the burn is also important. Particularly dangerous are burns of the face and throat area because of the high risk of injury to the respiratory tract, resulting in its closure due to laryngeal oedema. There is also the risk of poisoning by carbon monoxide and - within closed rooms - prussic acid. Shock is always to be expected in a burn victim. Besides the far-reaching damage to the whole organism there is also very severe pain. Any pre-existing pathological condition will cause other aggravating effects.
The following procedures are recommended at the scene of accident:
In burn victims first-aid procedures at the scene of accident are extremely important for future survival. The main thing is to remove victims from the injurious heat source. Flames must be put out, and hot, drenched clothes removed. Immediate cooling with cold water is a very effective procedure that has to be performed for at least 15 min. This also protects the skin from the “after-burn effect” and from any increase in burn depth. The burned regions should be kept as sterile as possible, without any cleaning.
First- and second-degree burns cause the severest pain, also involving shock, and pain relief is an important procedure. Doses of analgesics must be given i.v. because of shock-dependent circulatory irregularities. Morphine derivatives combined with a sedative are the agents of choice.
A permanent venous catheter has to be placed by means of which a solution of electrolytes and glucose-lactates should be given in a ratio of 1:l within the first 120 min. A dosage of only plasma expanders and hypertonic solutions would dry up the interstitium and the intercellular area, and as the blood circulation is overloaded this might result in cardiac insufficiency.
Transport then has to be organized, involving the choice of further medical treatment depending on burn extent and the patient’s age.
First- and second-degree burns with an extent of up to 5% can be treated in a surgical ambulance. However, if the face, hands, and joints are involved, the patient should always be referred to a hospital. Patients with minor burns but with attendant injuries, as also with second- and third-degree burns with an extent of up to 20%, should be referred to the nearest hospital. Adults with more than 20% burned BSA, children under 2 yr, adults of 60 yr and over with a burned BSA of 15%, and patients suspected of having burns in the respiratory tract must all be referred directly to an intensive care unit or taken to a specialized ward.
If the sum of the percentage of burned BSA and the age of the patient in years is 80 or more, the prognosis is very unfavourable. Thus a 60-yr-old patient with a burned BSA of 50% may be taken to any nearby hospital, as he has hardly any chance of survival.
During transport, patients with burns in the face and throat area can be given priority as respiratory disorders may require intubation.
Extensive burns cause disorders in general functions, which after some hours always lead to the irreversible collapse of all vital functions. First of all hypovolaemia occurs, leading to a loss of circulating blood of up to 15-30% after only 1-2 h. The symptoms are similar to those caused by shock, but additionally they damage the burned areas. There is also an uncontrollable loss of liquids, lasting up to four days.
Hypovolaemia leads to an increase of liquid accumulation in the burned tissue and, as a result, of colloid-osmotic pressure - i.e., sequestration. The blood flowing back from this area is hypotonic to the entire organism, also making possible an increase in liquid receptivity. There is a likelihood of oedema in the liver, kidney, and brain, with the danger of cerebral oedema. This causes conditions of confusion and restlessness.
There is also an increased loss of liquid through injured capillaries and cell membranes that continues throughout the healing process. Another loss of liquid develops owing to “evaporation” from extensive wound areas - this evaporation amounts to 1200 ml per day with a burned BSA of only 10%. There is also an accumulation of sodium in the burn areas. The change in the liquid and electrolyte balance - intracellular calcium is exchanged for extracellular sodium - also changes the total capacity of extracellular liquids, and the sodium level in the serum is reduced. With reduced renal function there is an increase in potassium against the sodium losses by released calcium, flowing directly from the cells via cell substructures. If fluid intake is too low, renal functions will be damaged, as will eventually become manifest.
Tissue hypoxia causes an increase in lactates, leading to intracellular acidosis, the extent of which cannot be measured because of imbalances in the microcirculation. Burn patients always present an excessive catabolism. The high loss of secretions and the simultaneous onset of infection cause a negative protein balance, as there is an extremely high consumption of additional calories due to evaporation. For this reason severe infection may bring high fever. The regeneration process also necessitates additional energy demands. The burn areas must therefore be covered as soon as possible. Only then will it be possible to reduce the almost impossible supply of calories.
Renal functions are reduced by shock, and filtration pressure is limited in the vas afferens owing to shock. There is a parallel contraction of the vas afferens that makes the oxygen uptake insufficient, especially in the marking zone. This leads to permanent tubulonecrosis. Maintenance of filtration pressure is absolutely necessary. Urine excretion must be checked every hour - it must not fall below 30-50 ml.
After a burn, blood circulation in the skin, intestine, and muscular system is reduced by vasoconstriction for the maintenance of blood circulation in all essential organs. This causes an increase in the flow resistance of blood. The heart has to pump against increased resistance and may become insufficient because of the possibility of oedema. An additional threat is the tendency for an aggregation of thrombocytes and erythrocytes. The additional hypoxia leads to the occurrence of permanent myocardial necroses, even in younger patients.
As a result of the long-lasting shock situation, the patient is threatened by stress ulcers. This may lead to anaemia, which also develops because of the perishing of erythrocytes after burn injury. Erythropoiesis is also disturbed. Substitution with fresh blood and units of stored warm blood is therefore necessary and diagnostic drawing of blood should not be underestimated. Disturbances in blood clotting have already been mentioned - they can promote the formation of microclots that can cause consumption coagulopathy and pulmonary embolisms.
The formation of "shock lung" poses a much more difficult problem. During the phase of reabsorption of sequestered liquids, the excessive parenteral amount of liquid inundates the alveolar wall in oedematous manner, and oxygen restoration to the lung becomes more difficult or does not occur at all. Additionally, secretions will press into the alveoli, causing lung oedema and suffocating the patient. Radiography of the lungs reveals “snow- and furry-like” spotted shadows. These signs, in combination with dyspnoea and thanatophobia, may require the use of immediate intubation and high-pressure respiration with an ample supply of oxygen.
Jaundice is another complication. This may occur as a result of the extensive decay of erythrocytes promoted by septic processes and activation of the RES system. Well-developed disorders of the immunological system are related to the specific and unspecific defence system. RES cells are damaged by hypoxia. They may also be blocked by doses of penicillin or vital pigments, as vital pigments have a contra-induced function for the differentiation of third-degree injured areas. Granulocytes are also disturbed in their enzyme system. The antigen-antibody reaction is injured by a considerable reduction in T-cells which reflects the cellular immune reaction. As the production of immunoglobulins is also reduced, high doses must be delivered.
The demanding activities involved in the treatment and nursing of severely burned patients need first of all an appropriate therapy unit. This unit must be sealed off from other places of clinical treatment, with its own air-conditioning system and bathroom unit, as well as a sluice for the changing of clothes by the nursing staff. The team of physicians and nurses must be well versed in the treatment of burn victims. Working under sterile and operative procedure conditions is the rule in this particular kind of burn treatment.
The main procedure, under sufficient analgesics, is infective prophylaxis. A parenteral dose of antibiotics has to be administered as prophylaxis against pneumonia, but a sufficient amount of drugs cannot be brought to the place of burn because of the necrosis wall. The patient must be given frequent showers above a bowl, especially in the anogenital area. Various disinfectants and even tanning drugs must be applied to the wound. In our hospital we favour immediate coverage of burn wounds with sterile fresh-frozen porcine skin after removal of skin also scraps and necroses. This can be kept in store, even in a refrigerator, without any problems. Porcine skin adheres to the wound area, preventing excessive evaporation and working against infection. Coverage with porcine skin (Fig. 3) leads to enormous additional pain relief, and the patient can be mobilized immediately, which is particularly important in hand burns. Daily, painful changes of dressing material are thus unnecessary as porcine skin is removed<% immagine "Fig. 3","gr0000003.jpg","Burn wounds with covering of sterile, fresh-frozen porcine skin as a collagenate forming a primary wound dressing. With porcineskin, paintful daily dressing changes become unnecessary: essenttially it provides additional prevention against infections by adhering to the wiund area.",230 %>
by itself, resulting in very tender burn scars with less formation of keloids (Figs. 4,5).<% immagine "Fig. 4","gr0000004.jpg","Tender burn scars after coverage of burn wounds with MEDISKIN - a collagene of fresh, sterile, frozen porcine skin.",230 %> <% immagine "Fig. 5","gr0000005.gif","Note the significant difference in the developement of disfiguring scars in burn wounds with conventional treatment and with primary dressing with MEDISKIN, depending on the rate of infection.",230 %>
The estimated depth and dimension of burns are recorded on special forms. The quantities of infusion are calculated every day and can be administered by means of a central venous catheter. Specific shock therapy will however always be the basis of all further infusion therapy.
High doses of corticosteroids can be administered, as they are a useful prophylaxis against pharyngeal, pulmonary, and even cerebral oedema.
A permanent bladder catheter completes first-aid appliances. Throughout treatment regular monitoring is necessary, with essential laboratory tests of electrolytes, clotting time, hepatic impairment, and blood glucose.
In the process of wound healing, the removal of necroses is useful for further prevention against infection and for the elimination of toxins from decayed tissue. In so doing, the wound area is prepared for coverage with an intrinsic skin graft. Necroses can be cleared away vertically, causing heavy haemorrhage, even tangentially, from a centric incision in layers right into the depth of the wound. In drastic necrotic excisions it is important to maintain a maximum amount of vital structures. The wound area is later covered with an intrinsic skin graft. If the wound area is extensive, the mesh graft method can be used: a cleavage skin flap is cut, using a matrix, into a pattern of lattices, so that the skin flap can be extended two- to five-fold. No more than 20% of the skin should be taken in one sitting.
Foreign skin grafts can be used but are very expensive because of the difficulties of production and large-scale refrigerating for storage. Typified foreign skin is also very expensive to apply and is also less effective than homografts. Allografts have to be changed every day, causing the patient pain and interfering with granulation.
The psychological guidance and care of burn victims is important for successful therapeutic treatment as they are compelled to lie in “solitary confinement” without any visible signs of healing. After healing they need a protracted period of time for rehabilitation, often combined with plastic surgery, which in the end will allow these aesthetically injured patients to return to associate with other people.
This general overview gives an idea of the problems of the treatment and rehabilitation of burn victims. It also indicates the enormous costs of such treatment. Effective prevention must aim at keeping the number of burn injuries as low as possible. We therefore need the on-going education of non-professional figures and the co-operation of all physicians, especially those who work in companies with a high rate of burns occurring in the productive process. Wide-ranging education of non-professionals in relation to the consequences of burn diseases, to burn mortality rates, and to the high costs of clinical and nursing staff would surely result in a reduction in the number of burn accidents.
RESUME. Le nombre des personnes atteintes annuellement de brûlures en Allemagne et hospitalisées excède 9000 - et une thérapie efficace nécessite des connaissances profondes des "maladies des brûlures" et de leurs possibles conséquences dangereuses. Dans cet article, l’Auteur décrit en détail le développement des effects nuisibles des brûlures dans tout l’organisme comme aussi les effets sur les systèmes organiques vitaux (cerveau, rein, foie, etc). La détermination de l’extension précise des brûlures dépend de certaines règles qui sont très importantes pour calculer la thérapeutique, ce qui constitue un aspect fondamental en particulier des premier soins. Cette phase précoce détermine le progrès futur du patient. Après les importants premiers soins et le traitement secondaire en hôpital, les grands brûlés qui survivent ont besoin de soins spécialisés pour leur rééducation.