| disease | Frozen Frigidity Wound |
Local frostbite disease and systemic frostbite disease (frozen stiffness) mostly occur in accidents or during wartime, when the human body is exposed to sub-zero temperatures, such as encountering a snowstorm in the wild, being trapped in ice and snow, or being accidentally injured by refrigerants (liquid nitrogen, solid CO2, etc.) during work.
bubble_chart Pathological Changes
When a part of the human body is exposed to sub-zero temperatures, a strong vasoconstriction reaction occurs; if the exposure is prolonged or the temperature is very low, extracellular fluid and even intracellular fluid can form ice crystals. The damage from frostbite mainly occurs after thawing, with local vasodilation, congestion, exudation, and thrombosis; ice crystals in the tissue can increase the osmotic pressure of extracellular fluid or directly damage tissue cells subcutaneous node, leading to necrosis after thawing and inflammatory reactions in adjacent tissues.
When the entire body is exposed to low temperatures, in addition to strong peripheral vasoconstriction and shiver (muscle contraction) reactions, the body temperature decreases from the surface to the core (core body temperature decreases), causing damage to the heart blood vessels, brain, and other organs. If rescue is deficient, it can directly lead to death.
bubble_chart Clinical Manifestations
Local frostbite disease can be divided into 4 degrees according to the depth of injury. Before thawing, the affected skin is pale, cold, numb, and stabbing pain, making it difficult to distinguish its severity. After rewarming, the manifestations of wounds at different depths vary.
Ⅰ° frostbite disease: Injury to the epidermal layer. Local redness and swelling, with fever, itching, and stabbing pain (similar to grade I chilblain, but the course of frostbite disease is more distinct). The epidermis dries and peels off after a few days, healing without scarring.
Ⅱ° frostbite disease: Injury reaching the dermal layer. Local redness and swelling are more pronounced, with blister formation. The blisters contain serous fluid or slightly bloody fluid. There is subjective pain, but sensory testing reveals dullness. If there is no infection, the area may form a scab, which falls off and heals in 2-3 weeks, with little scarring. If infection occurs, the wound may ulcerate, leaving a scar after healing.Ⅲ° frostbite disease: Injury to the full thickness of the skin or deep into the subcutaneous tissue. The wound changes from pale to dark brown, with loss of sensation on testing. There is redness, swelling, and pain around the wound, and bloody blisters may appear. If there is no infection, the necrotic tissue dries and forms a scab, which gradually falls off and forms a granulation wound, healing very slowly and leaving a scar.
Ⅳ° frostbite disease: Injury deep into muscle, bone, and other tissues. The local manifestations are similar to Ⅲ° frostbite disease, with necrosis occurring at the injury site and inflammatory reactions around it. The depth often needs to be determined during treatment. It is prone to infection and wet gangrene; it can also worsen necrosis due to vascular lesions (endothelial injury, thrombosis, etc.). Functional impairment or disability often remains after healing.
Systemic frostbite disease initially presents with shivering, pallor, cyanosis, fatigue, weakness, yawning, etc., followed by limb stiffness, hallucinations, confusion, or even unconsciousness, arrhythmia, respiratory depression, and eventually cardiac and respiratory arrest. If the patient is rescued, their heartbeat and breathing may recover, but ventricular fibrillation, hypotension, shock, etc., are common; respiratory secretions may increase or pulmonary edema may occur; urine output may decrease or acute renal failure may occur; other organs may also experience dysfunction.
1. First Aid and Rewarming: Quickly remove the patient from the low-temperature environment and frozen objects. If clothing, shoes, socks, etc., are frozen together with the limbs, do not forcibly remove them. Instead, use warm water (around 40°C) to thaw the ice before removing or cutting them off. Immediately perform rapid local or whole-body rewarming, but avoid using a stove for baking. Soak the injured limb or the whole body in warm water at 38-42°C, ensuring sufficient water volume and stable temperature, to rewarm the local area within 20 minutes and the whole body within half an hour. It is preferable to soak until the extremities turn red and the skin temperature reaches around 36°C. Prolonged soaking can increase tissue metabolism, which is detrimental to recovery. During soaking, gently massage the uninjured parts to help improve blood circulation. If the patient feels pain, sedatives or analgesics can be used. Timely rewarming can alleviate local frostbite disease and facilitate the recovery of systemic frostbite disease. For those with sudden cardiac and respiratory arrest, perform cardiac compression and artificial respiration.
2. Treatment of Local Frostbite Disease: For first-degree frostbite, keep the wound clean and dry, and it can heal in a few days. For second-degree frostbite, after rewarming and disinfection, if the wound is dry, it can be wrapped with soft dry gauze; for larger blisters, the fluid inside can be aspirated and then wrapped with soft dry gauze, or exposed after applying frostbite ointment; if the wound is infected, use antibacterial wet gauze first, followed by frostbite ointment. Third and fourth-degree frostbites are mostly treated with exposure therapy, keeping the wound clean and dry; necrotic tissue is excised when the boundaries are clear. If infection occurs, adequate drainage is necessary; for those complicated by wet gangrene, amputation is often required.
3. Treatment of Systemic Frostbite Disease: After rewarming, the first priority is to prevent and treat shock and maintain respiratory function. Preventing and treating shock mainly involves fluid replacement, selection of vasoactive drugs, defibrillation, etc., but cerebral edema and renal insufficiency must be considered, hence diuretics are also needed. Maintaining respiratory function mainly involves keeping the airway clear, providing oxygen and respiratory stimulants, preventing and treating lung infections, etc. Other treatments include correcting acid-base and electrolyte imbalances, maintaining nutrition, etc. Systemic frostbite disease is often accompanied by local frostbite disease, so wound management should not be overlooked.
Personnel and troops working in cold conditions must be equipped with appropriate cold-weather gear. Individuals should adhere to the "three protections": ① Protection against cold: Wear loose, thick, and windproof clothing, minimize the body surface area exposed to low temperatures (using gloves, masks, ear covers, or head covers, etc.), and apply oil appropriately on exposed body surfaces. ② Protection against moisture: Keep clothing, shoes, and socks dry, and replace any wet items promptly; treat sweaty feet (e.g., with 5% formaldehyde solution, 5% boric acid powder, 15% alum powder, etc.). ③ Protection against stillness: Engage in appropriate activities in severe cold environments to avoid prolonged standing or squatting. Before entering a low-temperature environment, consume a sufficient amount of high-calorie food; however, avoid alcohol as it may lead to neglect of cold protection and could increase heat loss. Individuals expected to encounter extreme cold (such as entering high-altitude or high-latitude areas) should train their bodies to withstand cold in advance, such as through cold water baths or ice sports. Measures to prevent frostbite disease also involve communication setups during fieldwork and duty, as well as transportation vehicles at the base (such as helicopters). In summary, with adequate anti-freezing preparations, even when entering extremely cold regions and environments, frostbite disease can be prevented.
