Thermal burn

Introduction to thermal burns "Burn" can be caused by hot water, steam, flame, electric current, laser, radiation, acid, alkali, phosphorus and other factors. Commonly referred to or narrowly defined burns are thermal burns caused solely by high temperatures and are common in the clinic. Burns caused by other factors are called the cause, such as electric burns and chemical burns. The pathological changes of thermal burns depend on the heat source temperature and heating time. In addition, the occurrence and development of burns are also related to the patient's body conditions. For example, some debilitated patients may cause II when they use a hot water bottle of 40-50 °C. Degree burns are not related to the conduction of heat to tissues. For example, the systemic response of children with burns is often more severe than that of adults after the same area (% of body surface) and concentration of burns. basic knowledge The proportion of sickness: 0.01%-0.05% Susceptible people: no special people Mode of infection: non-infectious Complications: septic shock, acute respiratory failure, adult respiratory distress syndrome, pulmonary edema, sepsis, atelectasis, acute renal failure

Cause of thermal burn

Cause:

"Burn" can be caused by factors such as hot water, steam, flame, electric current, laser, radiation, acid, alkali, and phosphorus. Commonly referred to or narrowly defined burns are thermal burns caused solely by high temperatures and are common in the clinic. Burns caused by other factors are called the cause, such as electric burns and chemical burns. Thermal burns are caused by high temperatures such as hot water, steam, flames, and electric current.

Thermal burn prevention

The basic method to prevent organ syndrome after burns is to promptly correct hypovolemia, rapidly reverse shock, and prevent or reduce infection. At the same time, according to the specific conditions, focus on maintaining the function of certain organs. For example: oliguria, hemoglobin or urinary tract type, etc., should consider blood volume deficiency, hemolysis or other renal damage factors, etc., to increase perfusion, diuresis, urinary phlegm, stop the antibiotics that damage the kidney (such as gentamicin , polymyxins and other measures. Pulmonary infection, atelectasis, etc., should actively suck and sputum, use antibacterial drugs, try to improve ventilation and oxygen.

Hot burn complications Complications septic shock acute respiratory failure adult respiratory distress syndrome pulmonary edema sepsis atelectasis acute renal failure

1. Shock: Most of the early stage is hypovolemic shock, and then concurrent infection may cause septic shock. The extraordinarily severe burns may be accompanied by shock and strong shock.

2. Sepsis: burns make the skin's barrier to bacteria appear defective; heavier patients also have weakened white blood cell function and immune function, so it is prone to infection, and the pathogen is the common bacteria of the skin (such as golden yellow grapes) Cocci, etc.) or exogenously contaminated bacteria (such as Pseudomonas aeruginosa), suppurative infection can occur on the wound surface and under the eschar, infection may also develop into sepsis, septic shock, in addition, widely used After antibiotics, especially in patients with weakened system, fungal infections can occur.

3. Pulmonary infection and acute respiratory failure: pulmonary infection may have multiple causes, such as respiratory mucosal burns, pulmonary edema, atelectasis, sepsis, etc., may also occur in adult respiratory distress syndrome or pulmonary infarction, leading to acute Respiratory failure.

4. Acute renal failure: renal ischemia before and after shock, severe renal capsule and renal tubule metamorphosis; hemoglobin, myoglobin, infection toxins can damage the kidney, it can lead to acute renal failure.

5. Stress ulcer and gastric dilatation: the duodenal mucosal erosion, ulcer, bleeding, etc. after burn, known as Curling ulcer, may be related to the gastrointestinal tract once ischemia, and the hydrogen ion countercurrent damage to the mucosa after reperfusion. Gastric dilatation is often caused by a large amount of water in the diseased population when the early gastric peristalsis is weakened.

6. Other myocardial function is reduced, stroke volume can be reduced: related to myocardial inhibitory factor, infection toxin or myocardial hypoxia after burn, cerebral edema or liver necrosis is also related to hypoxia, infection, etc., it is worth noting that burn Sickness is often caused by multiple system organ failure.

Symptoms of hot burns Common symptoms Drought blister edema Skin necrosis Mild burns Immunity Reduce acid burns Anxious burns pulse rate Increases irritability

The pathological changes of thermal burns depend on the heat source temperature and heating time. In addition, the occurrence and development of burns are also related to the patient's body conditions. For example, some debilitated patients may cause II when they use a hot water bottle of 40-50 °C. Degree burns are not related to the conduction of heat to tissues. For example, the systemic response of children with burns is often more severe than that of adults after the same area (% of body surface) and concentration of burns.

Pathological changes, in addition to the local tissue damage caused by high temperature, caused by various reactions of the body, the body reaction may be released after burn: 1 stress hormone, due to pain stimulation, blood volume reduction, etc., catecholamine, corticosteroid, anti- Increased release of diuretic hormone, vasopressin, aldosterone, etc.; 2 inflammatory mediators, due to damage to tissue cells in the wound or contaminated bacteria, bradykinin, complement fragments (C3a, C5a, etc.), histamine, tryptamine, etc. 3; Arachidonic acid becomes prostaglandin (PG), thrombosis (TX) and leukotriene (LT) due to the action of phospholipase, etc. 4 various other factors, such as platelet active factor (PAF), interleukin ( IL), tumor necrosis factor (TNF), etc., a variety of biologically active substances can cause local inflammation and systemic reactions of burns, such as glucocorticoids, indomethacin and other drugs, can reduce the body's response, but can only be used properly, otherwise It can increase complications.

In order to properly deal with thermal burns, we must first determine the area and depth of the burn, but also closely observe the changes in the wound and the general condition, and should be aware of the occurrence of complications.

1. The area and depth of burns

As mentioned above, these two conditions are closely related to the severity of the condition.

1. The estimation of the area is expressed in % of the surface area of the burned area. The researchers have proposed several estimation methods. The new Chinese nine-point method and the palm method are available in China, and the latter uses small area burns.

The new nine-point method is to set the human body as 9% right, which is mainly suitable for adults. For children with large head and fewer lower limbs, it should be slightly modified. The specific method is shown in Table 1; Attached to the medical record to indicate.

2. Identification of the concentration According to the level of thermal damage to the tissue, the burn is divided into 1 °, shallow II °, deep II ° and III °.

I° burns: only the epidermis is injured, and the area is red and swollen, so it is also called erythema burn; there is pain and burning pain, the skin temperature is slightly increased, and it can be cured after 3 to 5 days, and desquamation without leaving scars.

II ° burn: deep into the dermis, local blisters, so also known as vesicular burns, 1 selected II ° only injured the shallow layer of the dermis, part of the germinal layer is healthy, due to more exudation, blisters are full, after rupture Wound surface exudation is obvious; the base is swollen and red; there is severe pain and hyperesthesia; the skin temperature is increased, if there is no infection and other complications, it can be cured in about 2 weeks, no scars will be left after the healing, and there may be pigmentation in the short term, and the skin function is good. 2 deep II ° injury and deep dermis, skin attachment remains, because the surface layer of the south is slightly thicker, the blisters are smaller or thinner, the feeling is slightly dull, the skin temperature can be slightly lower, the skin is light red after the epidermis Or red and white, or visible mesh embolization of blood vessels; surface exudate is less, but the bottom swelling is obvious, if there is no infection and other complications, 3 to 4 weeks can be more, because there is some granulation tissue in the middle of the repair process, so there are scars, but basic Saved skin function.

2. Burn severity indexing

In order to design a treatment plan, especially when dealing with a group of wounded people, to organize manpower, material conditions, and to distinguish the severity of burns, the following indexing methods are commonly used in China:

Mild burns: II° burns less than 9%.

Moderate burns: 2% to 29% of II° burns; or less than 10% of III° burns.

Severe burns: total area 30% ~ 49%; or III ° burn area 10% ~ 19%; or II °, III ° burn area does not reach the above percentage, but shock and other complications have occurred, respiratory tract burns or heavier Combined injury.

Extra heavy burns: more than 50% of the total area; or more than 20% of III° burns; or serious complications.

In addition, clinically, it is often referred to as small, medium and large-area burns, in order to show its damage, but the classification criteria are long and clear, so the medical records should still clearly define the area and concentration.

3. Local lesions

After heat is applied to the skin and mucous membranes, cells of different levels are metamorphosed due to protein denaturation and enzyme inactivation, necrosis, and then shedding or becoming sputum. The strong heat can make the skin and even the deep tissues char.

Capillaries in the burned area and its adjacent tissues may undergo congestion, exudation, thrombosis, etc. Exudation is the result of increased vascular permeability. The exudate is a plasma component (a slightly lower protein concentration), which can form epidermal dermis. The edema between the blisters and other tissues.

Systemic response

Smaller area, shallower thermal burns, in addition to painful stimulation, the systemic effect is not obvious, the area is large, and deeper thermal burns can cause the following systemic changes.

1. Blood volume reduction Within 24 to 48 hours after injury, capillary permeability is increased, plasma components are lost to the interstitial (third gap), inside or outside the blisters (after rupture of the blisters), so the blood volume is reduced, serious After the burn, in addition to the exudation at the injury site, other parts may also have increased vascular permeability due to the action of the inflammatory mediator of the receptor fluid, so the blood volume is further reduced. In addition to exudation, the burned area accelerates due to loss of skin function. Increased dehydration.

When the blood volume is reduced, the body regulates by the neuroendocrine system, lowers the urinary tract of the kidney to retain the body fluid, and produces a thirst. The exudation of the capillaries can be reduced to a stop after the peak period, and the exudate can be gradually absorbed between the tissues. However, if the blood volume reduction exceeds the body's compensatory capacity, it can cause shock.

2. Energy deficiency and nitrogen negative balance After the injury, the body's energy consumption increases, catabolism accelerates, and nitrogen negative balance occurs.

3. Heavier red blood cell loss can reduce red blood cell count, which may be due to intravascular coagulation, red blood cell deposition, red blood cell morphology is easily destroyed or engulfed by the reticuloendothelial system, so red blood proteinuria and anemia may occur.

4. Immune function reduces hypoproteinemia after injury, increased oxygen free radicals, and release of certain factors (such as PGI2, IL-6, TNF, etc.) can reduce immunity; neutrophil chemotaxis, The phagocytosis and killing effects are also weakened, so burns are easily complicated by infection.

5. Systemic reactions and complications

The severity of moderate to high burns actually includes systemic reactions and complications. Complications may even cause a risk of mild burn patients. Prevention or reduction of complications may prompt burn patients to be cured or cured. Early manifestations of systemic reactions and complications of burns.

The performance of hypovolemia, mainly thirst, dry lips, oliguria, increased pulse rate, low blood pressure, increased red blood cell ratio, etc., such as shock, may be irritated or indifferent, unresponsive, cold sweat or The limbs are cool and wet, the pulse is weak or unclear, the blood pressure is obviously reduced or not detected, the urine volume is very small or the catheter is able to observe the urine volume, and the central venous pressure is lowered.

Burns are easy to be infected, and the suppuration on the wound is easy to find. Necrotic tissue, infection under the eschar and systemic infection may be neglected. At this time, the patient's body temperature rises significantly, and the percentage of white blood cells and their neutrality increases significantly. It can be reduced, white blood cells can not increase or decrease, wound secretion and blood should be taken for bacterial culture and drug sensitivity test.

It is also necessary to monitor the function of important organs such as kidney and lung according to the severe burn procedure. For example, to change the renal function, in addition to calculating the urine volume per hour, it is also necessary to test the urine routine (including specific gravity), and determine blood/urinary creatinine, blood/urine sodium. Etc., changes in the lungs, in addition to the physical examination of the respiratory system, when necessary X-ray chest radiographs and blood gas analysis and other tests, in short, timely detection and diagnosis of various complications of burns, in order to take timely treatment.

Hot burn inspection

Burns can also be distinguished by total surface area ratio (TBSA) and then by depth. Once burns (only erythema, no blister) are not included. The commonly used method, called the nine-point method, helps doctors quickly determine the body surface area of a patient's injury. A more precise method is to distinguish between different proportions of the body of an adult and a child through the Lund-Broude table. A person's hand (palm and finger) is about 1% of the total surface area. The actual average surface area should be 0.8%, so using 1% may slightly overestimate the burn area. 10% of children with burns and 15% of adult burns may have a life-threatening risk due to reduced blood volume and need to be infused as soon as possible and monitored in the burn department.

(1) Nine-point method (adult): 9% (1 9%) of the head and neck, 18% (2 9%) of the upper limbs, 27% (3 9%) of the trunk (including the perineum 1%), and both lower limbs ( Containing buttocks) is 46% (5 9% + 1%), a total of 11X9% + 1% = 100%.

(2) Nine-point method (children): The head of the child is small and small, and varies with age. The calculation is as follows: head and neck body surface area (%) = 9% + (12-age)%, double lower limb surface area (%) =46%-(12-age).

Thermal burn diagnosis

Damage caused by flames, high temperature solids, and intense radiant heat is called burns. Burns are tissue damage caused by high temperatures, chemicals or electricity. The degree of burn varies depending on the temperature and duration of the action. Local changes can be divided into four degrees. When burned, the amount of lactic acid in the blood increased, and the pH of the arteriovenous blood decreased. As the capillary dysfunction of the tissue worsened, the hypoxemia also increased. Burns can be life-threatening when they reach more than one-third of the body surface area.

The material in this site is intended to be of general informational use and is not intended to constitute medical advice, probable diagnosis, or recommended treatments.