burn

burn

injury to tissues caused by contact with dry heat (fire), moist heat (steam or liquid), chemicals, electricity, lightning, or radiation. Safety measures in the home and on the job are extremely important in the prevention of burns. Burns have traditionally been classified according to degree: A first-degree burn involves a reddening of the skin area. In a second-degree burn the skin is blistered. A third-degree burn is the most serious type, involving damage to the deeper layers of the skin with necrosis through the entire skin. In some cases the growth cells of the tissues in the burned area may be destroyed. See accompanying table.

Another classification describes burns as partial-thickness wounds in which the epithelializing elements remain intact, and full-thickness wounds in which all of the epithelializing elements and those lining the sweat glands, hair follicles, and sebaceous glands are destroyed. A deep thermal burn is a deep partial-thickness wound that may have the white, waxy appearance of a full-thickness burn.

It is difficult to determine the depth of a wound at first glance, but any burn involving more than 15 per cent of the body surface is considered serious. Because surface area as well as depth is important in evaluating a burned patient's status, a method called the rule of nines has been developed to determine surface area involvement. The head and each arm are figured at 9 per cent. The anterior and posterior trunk and the two legs comprise 18 or (2×9) per cent each, and the perineum is figured as 1 per cent. An improvement on the rule of nines, the berkow formula. takes into account the age of the burn victim.

In a burn the crust is the dry, scablike covering that forms over a superficial burn. eschar is a hard layer of tissue that results from full-thickness injury. It is considered to be a protective covering over the wound, serving as a barrier to bacterial invasion. Research indicates that eschar may be viable tissue that can contribute to healing and the prevention of scarring.

Immediate Treatment. The following steps should be taken for prompt and effective treatment of the various types of burns.

Major Burns. A burn is classified as major if it meets the following criteria: (1) in children, one that involves 10 to 15 per cent of total body surface and is a second- or third-degree burn; (2) in adults, one involving 25 to 30 per cent of total body surface, with deep partial-thickness or full-thickness destruction of epithelializing structures; (3) in children and adults, electrical burns, burns of the face and hands, or those that have traumatized the bronchi and lungs.

Emergency care at the scene of the injury includes application of cool water to neutralize the continued thermal effects of the burn agent and to dilute and wash away any chemicals that may be on the skin. In order to avoid shock. no more than 10 to 20 per cent of the burned area should be cooled at one time. If there is evidence of a major burn, it is necessary to establish and maintain an airway. Respiratory problems are especially likely if the person was burned in an enclosed place or was burned on the face and neck. Singed nasal hairs, darkened oral and nasal membranes, hoarseness, and carbon particles in the sputum are indicative of thermal injury to the respiratory tract.

The victim should be wrapped in a clean, preferably sterile, sheet. A blanket is used to cover the unaffected areas and to maintain normal body temperature if possible. If available, an intravenous infusion of Ringer's lactate solution is begun. If intravenous therapy is not available and the victim is conscious and able to swallow, fluids can be given by mouth. Nausea, vomiting, and ileus contraindicate the administration of any food or liquids.

Clothing is removed from the burned area only if this does not further traumatize the skin. Burned clothing should be sent to the burn center, as it may help determine the chemicals and other substances that either caused or entered the wound. Absorbent cotton, oily salves, ointments, and creams should not be applied to moderate and severe burns. Blisters are not opened or disturbed in any way.

Minor Burns. For a small first-degree burn, the reddened area is immersed in clean cold water, or ice cubes are applied. This relieves the pain.

Even first-degree burns are extremely serious if they involve a large area. They should receive prompt medical attention. Death may result if a first-degree burn covers as much as two thirds of the body area. On a child such burns are dangerous on a smaller area of the skin.

Chemical and Other Burns. For chemical burns, such as those caused by acids, the affected area should be bathed immediately with water, using plenty of water and continuing bathing the area until all of the chemical has been washed away. A health care worker should be called and first aid treatment should be given as for any similar heat burn. If the burned area is extensive, the victim should be given emergency care for a major burn.

If the area affected is the eye, it is held open and flushed gently but thoroughly with water. Then it is covered with a sterile dressing and medical aid is sought immediately.

In electrical burns, shock is the main danger. It may be necessary to use artificial respiration. This should be begun as soon as contact with the current has been broken. A person stricken by lightning also requires artificial respiration if the shock has been severe enough to interfere with normal breathing.

Hospital Treatment. A major burn presents problems of respiratory impairment, disruption of fluid and electrolyte balance, disturbances of tissue perfusion and homeostasis, and the potential for infection, delayed healing, and unnecessary scarring. Long-term effects also include orthopedic deformities resulting from immobility.

In the United States, most severely burned patients are given emergency care in a local hospital and then transferred to a large burn center for intensive long-term care. Patients who show signs of trauma to the respiratory tract must be watched closely for signs of developing laryngeal edema and obstruction of the air passages. This condition can develop any time from 4 to 48 hours after the accident. When wheezing on inhalation or other signs of respiratory distress occur,

intubation, frequent suctioning, and ventilator assistance may be needed.

Fluid loss by the evaporation of free water through the burned area causes disturbances in the extracellular and intracellular fluids. This can lead to burn shock, renal damage, and other life-threatening conditions. In addition to a loss of body water and changes in fluid composition, there are alterations in the composition of blood and the development of metabolic acidosis. If untreated, the changes in volume, concentration, and composition of extracellular fluid can be fatal. Information about the specific kinds of intravenous fluids that should be administered should be obtained from the burn center to which the patient will be transferred so that there is no break in the continuity of patient care.

In order to avoid nausea, vomiting, and the gastric and intestinal distention resulting from decreased peristaltic activity, a nasogastric tube is inserted and gentle suction applied. A retention catheter is inserted into the urinary bladder to obtain accurate measurement of output and periodic urine specimens for the determination of specific gravity and the presence of protein and blood.

In the emergency department. the burn wounds are cleansed according to established protocol, using clean technique and avoiding excessive loss of body heat. The cleansed wounds are then usually covered with dry sterile dressings, or with saline-soaked dressings that are covered with dry bandages before the patient is transferred. Exposed bone and tendon must be kept moist at all times with sterile saline-soaked dressings.

The major cause of death in burn victims is infection. Immunization against tetanus by administration of tetanus toxoid is recommended. If the patient has not received basic immunization prior to injury, he is also given tetanus immune globulin (Hyper-Tet).

The kind of environment provided in special burn units in large medical centers varies, but all have the objectives of avoiding contamination of the wound. Some special units use complete reverse isolation precautions and elaborate laminar air flow systems to maintain an environment that is as free of microorganisms as possible.

When the patient is cared for in a general hospital, it is recommended that some form of reverse isolation be used. Every effort should be made to protect the patient from autocontamination as well as from contamination from others and from the environment. It has been estimated that more than half of all burn wound infections can be traced to contamination by microorganisms such as Staphylococcus that originate in the patient. Physically isolating the patient from others should not be allowed to foster neglect and failure to attend to basic principles of cleanliness and good personal hygiene in day-to-day care.

Burn wounds can be treated in either of two ways: open or closed methods of therapy. In the open, exposed method of treatment no dressings are applied. Every effort is made to avoid disturbance of the eschar and the introduction of pathogenic microorganisms into the wound. If, however, the eschar causes a circumferential constriction of the trunk or an extremity, an escharotomy is indicated to prevent ischemic necrosis. antimicrobial agents are given systemically and, if the open method is used, they are applied topically. Examples of these topical medications include silver nitrate, silver sulfadiazine cream, and mafenide acetate.

The closed method of treatment may involve the application of dry occlusive dressings or wet dressings soaked in saline or some other solution preferred by the physician. The wet dressings require frequent changes when there is much exudate from the wound.

Immersion in water is especially helpful in cleansing the wound, removing debris and caked creams, and therapeutic exercise is essential to avoid orthopedic deformities. See also hydrotherapy .

Skin grafting is done soon after the initial injury. The donor skin is best taken from the patient, but when this is not possible, the skin of a matched donor can be used. Prior to grafting, or in some cases as a substitute for it, the burn may be covered with either cadaver or porcine (pig) skin to keep it moist and free from exogenous bacterial infection.

Patient Care. The primary concerns in patient care are prevention of infection, avoidance of a fluid and electrolyte imbalance, and prevention of such orthopedic deformities as contractures and ankylosis. If the patient is confined to a bed or frame, all the hazards of immobility must be guarded against. In addition to these measures, it is especially important that good sanitation practices and sterile technique be carried out faithfully. Handwashing is of vital importance.

The patient must be protected from extremes of heat and cold whether dry or wet dressings are used. Dry dressings, which do not allow for circulation of air, can cause a buildup of body heat, especially in a febrile patient. The patient receiving wet dressings must be protected from drafts and other conditions that could produce chilling.

Careful and accurate taking and recording of vital signs is done periodically and any significant change reported immediately. An accurate record of intake and output is of primary importance. Because large amounts of body fluids and many essential minerals and salts can escape through burn wounds, it is imperative that a record be kept of fluids excreted through the kidneys or intestinal tract or by emesis. Observations should include not only the amount but also the color, concentration, unusual odor, or any other characteristic of the urine, emesis, or liquid stool.

A high-protein diet with supplemental vitamins and minerals is prescribed to aid in the repair of damaged tissue. Ingenuity and imagination may be needed to encourage the patient to eat meals as well as the between-meal feedings prescribed.

The patient who has suffered disfigurement from burns will have additional emotional problems in adjusting to a new body image. Burn therapy can be long and tedious for the patient and family. They will need emotional and psychological support as well as attention to their spiritual needs as they work their way through the many problems created by the physical and emotional trauma of a major burn.

acid burn injury to tissues caused by an acid, such as sulfuric acid or nitric acid. Emergency first aid for an acid burn of the skin includes immediate and thorough washing of the burn with water for 20 minutes and transportation of the victim with extensive burns to an emergency care facility. See also discussion of Chemical and Other Burns, under burn .

Source: medical-dictionary.thefreedictionary.com

Category: Forex

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