Hello! According to the pathophysiological characteristics of burns, the course of the disease is roughly divided into three stages. However, this is an artificial staging, and the stages often overlap with each other. The purpose of staging is to highlight the focus of clinical treatment at each stage.

(1) Acute body fluid exudation stage (shock stage), the immediate reaction after tissue burn is body fluid exudation, which generally lasts for 36^48 hours. For small superficial burns, the amount of body fluid exudation is limited, and through the body's compensation, it will not affect the effective circulating blood volume throughout the body. Those with large and deep burns may experience sudden shock due to massive leakage of body fluids and other hemodynamic changes. Shock in the early stage of burns is basically hypovolemic shock, but it is different from general acute blood loss in that the exudation of body fluids is gradual. It is most acute 2-3 hours after the injury, reaches a peak at 8 hours, and then gradually slows down to 48 hours. The blood pressure tends to recover, and the edema fluid that seeps out between tissues begins to recover. The clinical manifestations are that blood pressure tends to stabilize and urine begins to increase. According to the above rules, the rehydration rate in the early stage of burns should be fast first and then slow.

(2) During the recovery period of burn edema during the infection period, infection becomes the main conflict from the very beginning. If superficial burns are not treated properly in the early stage, periwound inflammation (such as cellulitis) may occur. Due to the impact of shock, severe burns leave the body's immune function in a sluggish state and are highly susceptible to pathogenic bacteria. The probability of early outbreak of systemic infection is also high, and the prognosis is the most serious. An important experience in the treatment of burns in my country is that timely correction of shock has the meaning of anti-infection.

The threat of infection will continue until the wound heals. Burns are characterized by extensive physiological barrier damage, extensive necrotic tissue and exudation, which are good culture media for microorganisms. Thermal damage to tissue begins with coagulative necrosis, followed by tissue dissolution. 2-3 weeks after injury, the stage of extensive tissue dissolution is another peak period of systemic infection. Granulation tissue at the junction of tissues also gradually forms. If the necrotic tissue can be removed or drained in time, the granulation tissue barrier will mostly form in about 2 weeks, which can limit the invasion of pathogenic bacteria. If not handled properly, pathogenic bacteria can invade adjacent non-burned tissues. In large-scale invasive infections, the bacterial count in the underlying tissue often exceeds 105/g. If the bacterial count continues to increase, burn wound sepsis can occur.

If the wound appears dark, rotten, sunken, and has necrotic spots, even if the bacteria have not invaded the blood, early incision or resection surgery and timely skin transplantation are often used to eliminate the wound. When the wound is basically repaired, complications are significantly

reduced.

(3) Repair period. After tissue burns, while the inflammatory response occurs, tissue repair has also begun. Most superficial burns can be repaired by themselves, deep burns of 11" can be repaired by the fusion of the remaining epithelial islands, and burns of 111" can be repaired by skin transplantation.

At present, most of the work of excision of burnt necrotic tissue and skin transplantation has been carried out during the infection period. In the repair period, only some residual and sporadic small wounds are repaired, and some joints and functional parts are repaired. Measures and exercises to prevent contracture and deformity. The recovery process for large and deep burns takes a long time, and some may require plastic surgery.

Wish you good health!