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Experience in the treatment of 16 cases of finger burns caused by hydrofluoric acid (continued) Hydrofluoric acid； Burns ； Fingers Hydrofluoric acid (HF) is a strong inorganic acid that is commonly used in fluoride production, semiconductor manufacturing, and the metal processing industry; it can also be used as a catalyst in petroleum products. Due to its widespread use in production, accidental burns are likely to occur. Due to its strong permeability and corrosiveness toward biological tissues, hydrofluoric acid can easily penetrate through intact skin and the lipid barrier to reach deeper subcutaneous tissues, even reaching bone tissue. If not treated promptly, even minor burns can lead to serious consequences, including death. We present below our experience in treating 16 patients with finger burns caused by hydrofluoric acid, who were admitted to our hospital from October 2003 to June 2005. 1 Clinical Data 1.1 General Information: Among the 16 patients in this group, there were 14 males and 2 females, with ages ranging from 25 to 53 years, and an average age of 34.8 years. Among them, there were 4 cases of burns to a single finger, 12 cases of burns to two or more fingers; 12 cases were grade II burns, and 4 cases were grade III burns. The burn area ranged from 0.35 to 5 cm2, with an average of 1.68 cm2. The earliest time of seeking medical attention was 30 minutes after the injury, and the latest was 12 hours after the injury. The 4 patients washed the affected area with tap water for about 5 minutes immediately after the injury, while the remaining 12 patients did not receive any treatment. All 16 patients arrived at the emergency department after experiencing severe pain. 1?2 Treatment Methods 1?2?1 Early first-aid measures: Upon arrival at the hospital, the wound should be thoroughly rinsed with plenty of running water to remove as much debris from its surface as possible; special attention should be paid to rinsing the nail area and nail folds for an extended period of time. Afterwards, the wound should be rinsed several times with isotonic sodium bicarbonate solution or soapy water, in order to remove blister skin and any shed epidermal cells. 6 finger blisters were excised, and dark red exudate was drained. In 4 cases of nail bed burns with subungual effusion, nail removal was performed under local anesthesia. In 2 cases accompanied by necrosis at the distal phalanges, local debridement and partial resection of the necrotic distal phalanges were performed, followed by advancement repair using single or bilateral lateral finger flap transpositions. 1?2.2 Local or intravenous injection of calcium agents: 10% calcium gluconate is injected directly into the deeper layers of the injured wound; 1% procaine can also be added to reduce pain. When injecting, the needle should be inserted from healthy skin tissue, so as to avoid inserting it directly into the wound and thereby risking the introduction of hydrofluoric acid into deeper tissues and causing further damage. At the same time, 10 ml of 10% calcium gluconate was administered by intra-radial artery injection (from the proximal to the distal end), once daily; in the early stage, it could be given 2–3 times a day for 3–5 consecutive days. If the wound is large, there is a tendency to fluorosis, and hypocalcemia has already occurred, calcium should also be administered intravenously to maintain blood calcium levels within the normal range. A dosage of 20–40 ml per administration is appropriate; close monitoring of blood calcium levels and ECG readings is necessary. Treatment usually lasts for 3–5 days, with the relief of pain and normalization of blood calcium levels serving as indicators of its effectiveness. 1?2.3 Topical application of calcium agents: A medicated solution containing calcium ions, such as 20 ml of 10% calcium gluconate, is used to soak a piece of dry gauze; 10 g of silver-zinc cream is added to the gauze and mixed well, after which the mixture is applied to the wound area. This helps to bind surface fluoride ions, reducing their absorption and preventing damage to deeper tissues. The dressing should be changed every 4–6 hours, and this treatment should be continued for 3–5 days, depending on the reduction in the patient’s pain. Thereafter, silver-zinc ointment was used for dressing changes every other day until recovery. 1?2.4 Surgical treatment: For patients with deep burns over a large area, it is necessary to remove the necrotic tissue as soon as possible. This not only helps to prevent the progressive damage caused by fluoride ions but also facilitates earlier repair of the wound surface. Two patients in this group (1 with the index finger and 1 with the middle finger) had necrosis at the tips of their phalanges; after local debridement and partial resection of the necrotic phalanges, single or bilateral lateral interdigital flap transfer repairs were performed, resulting in good functional recovery upon healing. 1?3 Results: The healing time for the 22 hands (52 fingers) of the 16 patients ranged from 10 days after injury to 28 days after injury, with an average of 14.3 days; the function of the fingers was good after healing. In 5 patients with 5 hands (7 fingers), patchy necrosis occurred; after the scabs dissolved, small wounds formed, and these wounds healed on their own within 3 to 4 weeks following dressing changes ； 4 cases of nail bed burns, underwent nail removal ； 2 cases with phalangeal necrosis were treated with partial finger amputation. 2 Discussion Characteristics of hydrofluoric acid burns: (1) The wound caused by hydrofluoric acid goes through a series of changes; these changes are not easily noticeable at the initial stage of injury. The duration of these changes depends on the concentration of hydrofluoric acid and the time of exposure ； (2) The pain is more severe than that of ordinary burns; even when the burn area is small, the pain remains unbearable ； (3) The trauma progresses increasingly, initially manifesting as redness of the epidermis, followed by whitening; it advances from grade I to grade III, and may even reach the bone. The corrosive effect of hydrofluoric acid can cause liquefactive necrosis of tissues as well as decalcification of the bone in the affected area. Since nails lack a keratinized layer, it penetrates rapidly into the nail bed and matrix as well as into the phalanges, leading to involvement beneath the nail. The severe, delayed pain in these deeper areas is a key characteristic of this condition; systemically, it can cause hypocalcemia, which is the main cause of death. Individual cases in this group presented with the aforementioned local clinical manifestations; however, due to the small area of burn, no significant hypocalcemia occurred. The key to treatment is to rinse the wound thoroughly with plenty of flowing water immediately after the injury and to use a neutralizing agent. The flushing time should be at least 5 minutes, with an appropriate extension for skin folds. Timely and thorough rinsing can effectively remove residual hydrofluoric acid from the body surface, but due to its strong penetration ability, simple rinsing often fails to prevent further damage to tissues by hydrofluoric acid; therefore, a neutralizing agent must be used immediately after rinsing. In this group of patients, 10% calcium gluconate combined with 1% procaine was injected locally into the fingers in the early stage; this caused calcium ions and fluoride ions to combine to form calcium fluoride, thereby reducing lipid dissolution and the saponification of fats. As a result, bone decalcification was diminished, which in turn reduced the severity of tissue necrosis caused by hydrofluoric acid. Consequently, the wounds on the fingers of 12 of these patients healed within 2 weeks. Procaine can relieve pain, making it easier for patients to undergo treatment. As a treatment for finger burns, surgery is the fundamental approach, including local debridement and nail removal. If blisters are present, they should be removed; if there is burns to the nail bed, the nail must be removed. In cases of bone necrosis in the fingers, the necrotic bone segments need to be promptly removed so that flap reconstruction can be carried out. Otherwise, the continuous spread of fluoride ions will lead to an increase in the size of the wound area and progressive necrosis of the finger bones, affecting the length of the finger and ultimately compromising its function. In addition, the topical application of calcium gluconate and silver-zinc cream allows the remaining fluoride ions to form calcium fluoride; the silver-zinc cream also helps prevent and reduce wound infections, with zinc ions facilitating wound healing. The results of this study indicate that this method is not only simple to use but also highly effective. Author: Li Jun