This is the deadliest of the deadliest sections of the whole course. You have chemical injuries, frostbite, CRPS, infection, and now burns. We'll try to get through this and try to get to the question section here quickly. So I'll review burns. And snakebites is also shown up on the self-assessment exam. And so I'll have a couple slides at the end about snakebites. Again, any information on my slides or on the handouts that has an asterisk has been covered by the self-assessment exam in the past. Burns, 2 million burns per year, over 500,000 are treated in the emergency room, and 70,000 in burn units. Mortality is highest in a very young population, two to four. And there's another spike a little bit older between 17 and 25 years of age. Topics that have come up on the self-assessment exam, the most common burn in the pediatric population are scalding injuries. Also brought up cast burns. You put a plaster cast or plaster splint on. Do not put it on an elastic pillow or anything that will not allow the heat to dissipate. With the plaster, there's an exothermic reaction. And if the heat can't dissipate, you can develop a burn. So our treatment, evaluate the depth of the injury, determine need for escharotomy, splint, and local wound care. So we classify the burn by the depth of skin injury. Type 1 is epidermal injury only. These are very superficial injuries, may be as mild as a sunburn, basically. You have some edema, a little erythema, but your capre fill and sensation is still intact. And these typically heal without any scar and doesn't require any treatment. Secondary or second-degree burn is injury to the epidermal as well as some of the dermal layers. These are the patients that have the blister formation. And typically, the skin is repopulated by the germinal cells adjacent to the follicles. And here's a typical second-degree burn that we'll tend to see with a large blister, dorsal, MP area. Third-degree burn, epidermal, as well as the entire dermal layer, as well as the subdermal fat. These are those patients you see that tight, dry, inelastic tissue, that eschar that develops following the burn. Here's an example dorsal aspect of the hand of a third-degree burn. No blistering, but just that tight eschar that's developed. Fourth-degree burn involves dermis, subcutaneous tissues, but also the deep tissues. It can involve tendon, nerve, bone, and joint. How do we determine the depth? Well, our clinical exam is only good in about 60% to 75% of cases. We can consider biopsy, but that's really impractical. Laser Doppler has been used, but it's not really widely available and typically just used in research, as a research tool. The extent and depth really is related to the intensity and duration of contact. The heat, over time, will lead to edema, ischemia with necrosis, and then, in some cases, infection. Ischemic factors may be systemic. You have hypovolemia from the evaporation due to the capillary permeability. And so, patients that have severe burns, they require fluid resuscitation. Local factors, if you have an eschar, completely circumferential eschar, that will tend to lead to an ischemic event, leading to necrosis. An infection develops associated with that ischemia and the tissue necrosis. It can also be common in patients that have an immunocompromised process. And the problem with infection, it converts viable tissue into further necrotic tissue. And so, we try to prevent the infection from happening with prophylactic antibiotics. Pseudomonas is the most common cause of systemic sepsis with a burn. Management for significant burns. If it's greater than 25% of the body surface area, or if it's a young child or an elderly patient, greater than 20% of body surface area, transfer that patient to a burn center. In addition, if you have a high-voltage injury, inhalation injury, consider transfer. The objectives, we need to prevent edema. We want to prevent a contracture from poor position of the hand, which will tend to develop following a burn. Again, prevent infection and try to preserve all the viable tissues possible. So, first degree and second degree burns, symptomatic care. Quite often, just mild analgesia, anti-inflammatory medications. If they have a wound, local wound care, we typically use some type of non-adherent gauze dressing. Topical antibiotics, I typically use basitracin. If it's a patient has swelling, elevation. And if it's a more significant burn, consider splinting. We want to splint them into functional position and early range of motion to prevent scar contraction. Historically, we left the blisters intact, and that's not well-documented in the literature, whether that makes that much of a difference. We do know that wound desiccation will lead to a deeper injury, but there is a greater risk of infection if you have the necrotic tissue. The pro-inflammatory cytokines within the blister fluid may limit wound healing. So, we debride the blisters if they're limiting range of motion or if they've burst. And by debriding the blisters, you can get a better assessment of the depth of the burn. And after debridement, we cover it with an occlusive dressing and try to maintain some hydration of the burn. After epithelialization, consider a compression garment, and that has been shown to decrease scar height with a compression garment. Historically, we use silver silvazalidine ointment. That may delay wound healing. It adheres to the dressing. Particularly with frequent dressing changes, it can traumatize our epithelial cells, and it may be toxic to our regenerating cells. If you have a superficial partial thickness wound, consider some type of skin substitute. There's a BioBrain. It does have a silicone component to it that allows an epidermal barrier to decrease evaporation and provide hydration, but it's expensive. And then if the fluid collects, you have to puncture the dressing in order to allow it to drain. These burns will colonize in approximately seven days, and so you want to treat these patients with antibiotics if you think that the wound will, or burn will continue for greater than a week. We consider excision and grafting if the extent of the burn we believe will take longer than two or three weeks to heal. It's a little bit controversial whether you do an early excision and graft versus a late excision and graft. Late excision and graft, you wait until that eschar has fully demarcated. It separates from the tissues, excise it, and graft. There have been some studies that have shown that early excision does reduce hospital stay and fewer secondary procedures, but again, it's very controversial of which is best. When we do an excision, it's a tangential excision, and quite often you'll have multiple levels of injury, third degree, some second degree, we'll typically use an epi-soak sponge after the excision of the tissue down to the bleeding edges of the tissues in order to limit hematoma, and then split the skin graft at 15 one-thousandths of an inch since the full thickness graft has not been shown to improve the results over a split thickness graft. Typically don't mesh the graft since cosmetically it tends to be a better result with a non-mesh graft, although if it's a very extensive wound, we'll tend to mesh. Again, place the hand in an intrinsic plus position and maintain that first web space. We can use skin graft substitutes. It's a mechanical barrier to infection and fluid loss. It does decrease wound contracture, and they can be classified as epidermal, dermal, or dermal-epidermal substitutes. The dermal replacement, there's a bi-layer bovine collagen material that has a silicone surface. It's a two-stage procedure where at two to four weeks following placement, remove the silicone and skin graft over the top. And we tend to use the skin substitutes, the engineered skin substitutes for more extensive burns. Fourth-degree burns, once you get down to bone and tendon injuries, skin grafts aren't adequate. They typically need either flat coverage and quite often amputation. Escharotomy, main indication for escharotomy if you have poor perfusion, particularly in that patient that has that fully circumferential eschar. And again, main purpose is to improve perfusion of the limb. We can do these quite often bedside. Quite often, they're in the intensive care unit, IV sedation. We make mid-axial lines. You can make an incision from the acromion, you can make an incision from the acromion all the way down to the radial aspect of the wrist and hand. If it's a more extensive eschar, you can make a medial incision as well. Within the digits, it's in the mid-axial line. When digits long and indexed, we consider ulnar incisions, where the small finger will tend to perform a radial incision, just like when we drain an abscess in order to prevent that incision from being over that surface where you're typically leaning on the hand, on the ulnar aspect of the digit. Consider carpal tunnel release, as well as intrinsic muscle release with more extensive burns. We'll use intravenous antibiotics, more severe burns, and topical antibiotics, again, with those burns we accept to continue for over a week. Contractures, PIP contractures, usually flexion contractures. In more significant burns, it's related to loss of the central slip. With volar burns, you'll tend to develop that thick scar contraction, the palmar aspect of the digit. And it's also associated quite often that claw-type of deformity with the MP hyper-extension deformity. And these can be very, very severe contractures, requiring flap coverage. Sometimes just even doing a PIP contracture, or PIP fusion, is the easiest way to address this. First, web-space contractures, one of the most common burn contractures that require surgical management. We use a Z-plasty if we have adequate local tissues. And if flap coverage required, consider posterior interosseous flap, radial form, or a dorsal interosseous artery flap, or a dorsal ulnar artery flap, as shown up on the self-assessment exam in the past. Electrical burns, these injuries quite often are difficult to assess the extent. You may have an entrance and exit wound. Initially, appear to be very innocuous. Be careful, you may also have a skeletal injury. Patient falls following that electrical event. And quite often, with these electrical injuries, a compartment syndrome will develop. And so it's important to have a low threshold for fasciotomy. The severity of electrical burns depend on the voltage, amperage, current of the electrical injury, but also the resistance of the tissues that it's going through. Highest resistant tissue is bone, least is nerve. And so a low-voltage injury will extend through the nerve, whereas a high-voltage injury will be direct flow. So the nerve injury can be related to that low resistance of the tissue itself, but also can be related to progressive carpal tunnel syndrome or compartment syndrome. And so have a low threshold, again, for compartment release or carpal tunnel release. Out of all those factors, voltage is a major determinant in tissue damage. Fasciotomy within four to six hours is important. And quite often, you'll have to perform multiple debridements because of the extent of the injury. Definitive treatment quite often is amputation or flap coverage. And electrical burns have a higher rate of amputation in comparison to thermal burns. To finish up, a few slides on snake bites. 20% of snake bites are non-venomous. And if it is a venomous snake bite, 98% will be a pit viper, copperhead, water moccasin, or rattlesnake. And 2% are the coral snakes or elapid. Most of these will occur in the upper extremity. The crotylid or pit viper, usually you see the two discrete fang marks within the injury. With evenimation, a patient will develop local and sometimes systemic symptoms. If you do not have the symptoms with a pit viper bite by four hours, you probably didn't have any venimation. Patients can develop progressive symptoms, cardiac as well as neurologic symptoms post-injury. The elapid or coral snakes will have poorly developed fangs. It's more of a chewing action that they use in order for their bite. Most are non-venomous. But it can cause or lead to a significant neurologic process requiring antivenom. Pre-hospital, limit physical activity, place pressure on the area. But typically, we don't use tourniquets. Other important components, don't place ice with on the area of injury, since that can potentiate the necrotic effect of the snake venom. We assess their vital signs. We assess their coags. And then we consider antivenomation if there is evidence of systemic symptoms. I'll do one question here. Which of the following is the initial treatment after second degree burns? Early skin grafting, enzymatic debridement, splinting, tangential excision, or immediate escherotomy? Now, second degree burn, there's not going to be an escher. It's going to be a blister. Early skin grafting is very, very uncommon. You consider that for third degree burns. You're going to continue splinting in order to maintain the functional position of the hand and first web space. We end here, and then we can get started with the rest of the panel.

burns

snake bites

treatment options

venomous snakes

antivenom treatment