We’ve talked about various heat-and-cold injuries to the body: Cold Blows the Wind Today and Heat Stress. Now it’s time to talk about something a bit more acute and a bit less systemic: Traumatic burns.

The subject has been brushed by: Sumer Is Icumen In (Lightning Strikes) and we’ve even circled around the edges: Stop Drop and Roll.

Now it’s time to get into the guts (so to speak) of Burns. Burns are some of the most frightening injuries. They are some of the most painful injuries. And, they can be life-threatening.

Sorry, folks, no pictures. Y’all can find ‘em on your own.

While burn injuries are classified as trauma, they have some significant differences from most other kinds of trauma. Normally, after (say) blunt trauma (e.g. falling off a roof) the body responds by constricting blood vessels, increasing heart rate, forming clots, shifting fluid to the area to allow white cells to access the injury, and similar good stuff. By contrast, with a major burn, the body’s defense mechanisms paradoxically cause it to shut down, go into shock, and die. Vasoconstriction and clotting can increase the size and severity of the burn while so much fluid may shift that it will throw the body into hypovolemic shock. Treatment of burns, prehospital, focuses on stopping or reversing those processes.

First: Stay safe. You can’t help a patient if you become a patient yourself. Downed power lines stay dangerous until someone wearing a white hard hat says they’re safe.

Second: Stop the burning process. If someone is on fire, put them out.

While the flames (and the thermal burns they produce) are the dramatic part of fire, the most dangerous part of a fire is the smoke. A very small amount of smoke inhalation can be fatal. Smoke, in addition to the particulates, can carry carbon monoxide, hydrogen cyanide, sulfur dioxide, and other chemical goodies. Usually, unless you’re looking at a steam burn, you won’t see a lot of actual thermal injury inside the lungs. Dry air doesn’t carry a lot of heat. But those particulates and gasses can produce chemical burns to the lungs even if they aren’t directly poisonous, producing chemical pneumonia and … this is bad.

The amount of smoke inhaled is the number one predictor of mortality in burn injuries, way ahead of the age of the patient or the surface area of the burn. Continue to be suspicious with someone who has escaped from a fire. Sometimes the symptoms of smoke inhalation don’t appear for hours or days.

The importance of smoke became obvious after the Cocoanut Grove Fire in Boston in 1942. Seemingly uninjured people who had escaped the fire and come to the hospitals looking for friends were falling down and dying in the waiting rooms. The presence of plastics was what had changed: Some of plastics’ byproducts of combustion are purely nasty.

While burns are not just injuries of the skin, that’s where we’re going to start as we look at this kind of injury. Often the first signs of burn injury appear on the skin.

Your typical adult has somewhere around 1.5 to 2 square meters of skin, divided into two layers: The epidermis on top, and the dermis below that. Below the dermis come the subcutaneous layers. The skin of males is typically thicker than the skin of females. The skins of children (<5) and elderly (>65) are typically thinner than adults. The skin is the largest organ in the body. It has three primary functions: Infection control, heat regulation, and water control. Burn injuries compromise all three of these functions.

Sometimes you hear burns classified as superficial, partial thickness, and full thickness. The “thickness” referred to is the thickness of the skin. I’m going to use another system of nomenclature: First degree, second degree, third degree, and fourth degree.

Your body contains an awful lot of protein. Proteins are complex molecules that easily denature with heat. When the body is burned, the central, most highly damaged, part of the burn is called the zone of coagulation. Which is exactly what it sounds like: The tissues have been hard boiled. The proteins have coagulated. The cells there are dead; they will not regenerate. Another cheerful name for this zone is the “zone of necrosis.”

The area surrounding the zone of coagulation is the zone of stasis. The cells there aren’t dead, but they are injured. Blood isn’t flowing to them; nutrients aren’t getting to them; oxygen isn’t getting to them. Without oxygen and nutrients those cells will die, and the zone of necrosis will expand.

Around the zone of stasis is the zone of hyperemia. Cells in this area are damaged, but not too badly, and are getting increased blood flow; the increased blood flow is part of the body’s normal reaction to any injury. The blood vessels get “leaky” to allow fluid to enter the intercellular space (between the cells) which allows white blood cells to access all parts of the injury. This causes swelling (edema) as the area puffs up with water.

It’s deucedly difficult to tell how deep a burn is immediately after the injury using a Mark One Eyeball. A burn that appears superficial may actually be deep, and that fact may not be apparent for up to 48 hours after the injury (when the top layers of the skin slough off). That being said, let’s talk about burn depths.

First degree burns. These only involved the epidermis (from epi - above; dermis - skin). These are the ones that are also called “superficial.” The epidermis varies in thickness from 1/20 of a millimeter on the eyelids to 1 millimeter on the soles of the feet. The signs are redness, the symptoms are pain. Usually they heal by themselves within a week without scarring. Large area superficial burns risk dehydration and the pain may be intense. The classic first degree burn is sunburn. Drink a lot of water and avoid re-injuring the area before it’s healed.

Second degree burns. These are also called “partial thickness burns” because they go part-way through the dermis. The most obvious feature of second degree burns are surface blisters or bare patches with a wet, glistening appearance. Exactly how severe a second degree burn is depends on how deep it is and how it’s cared for. A comparatively shallow second degree burn, with circulation rapidly returned to the zone of stasis, can heal on its own with normal wound care in two to three weeks. A deeper second degree burn, or where the zone of stasis is allowed to progress to necrosis, may require surgical treatment. An improperly treated second degree burn can convert into a third degree burn. Which you’re looking at is hard to determine on-scene. Second degree burns are also quite painful. Even air moving across the skin may be unbearable. (This is because the epidermis may be gone so that the nerve endings are directly exposed to the environment.)

Third degree burns. Sometimes called “full thickness” burns. They go all the way through the dermis. These burns generally have a thick, dry, leathery, white appearance (regardless of the race or skin color of the patient). The skin may appear charred. Blood vessels may be obviously congealed. These burns require surgical care and rehabilitation in specialty centers.

While third degree burns are classically painless (since the nerves are completely destroyed), they are generally surrounded by areas of second and first degree burns which are exquisitely painful.

Fourth degree burns are those that penetrate the skin entirely, with damage to the underlying fat, muscle, bone, or organs.

Let’s talk about blisters for a minute. They occur when the epidermis separates from the dermis and the space beneath the epidermis fills with fluid leaking from the damaged tissues below. This fluid contains proteins; it therefore continues to draw water into itself by osmotic pressure. Thus, blisters tend to grow, putting pressure on the wound beneath and increasing pain. Blisters do not actually act as a barrier to infection since they are not normal skin. But the need to drain and debride them is handled in a burn center, not in the field. If/when a blister opens, topical antiseptics are used to help prevent infection. Secondary infections after burns can be life-threatening.

Burns produce a massive fluid shift inside the body, from the blood vessels to the intracelluar space. Even more fluid is lost through evaporation. This produces hypovolemic shock. The treatment for this is massive amounts of intravenous fluid; according to the Parkland Formula (named after the hospital where it was devised), that’s 4mL of normal saline IV per kilogram of body weight per percent of surface area burned, with half of it delivered in the first eight hours after the time of injury and the rest over the next sixteen hours.

Please note that while massive fluid shifts are taking place, they take place over a period of hours. If the patient is showing signs of shock immediately or over a period of minutes, there’s more going on than just the burns: Look for broken bones, lacerations, and other trauma. Someone who fell down stairs or jumped out a second-floor window trying to escape a fire has those injuries too and you’ll have to deal with them; they may kill the patient before the burn has a chance to do it. Burns are dramatic and grotesque injuries. Don’t let them distract you from noticing that the patient is also having a heart attack, diabetic emergency, stroke, or other medical problem.

So what do we do, in the field, for burns?

First, as mentioned, stop the burning process. This does not mean “cool the burn.” The best way to stop the burning process is by flooding the area with large amounts of tepid water. Applying cold water or ice is contraindicated because that has the effect of making the blood vessels in the area constrict. Constricted blood vessels stop blood flow. But we’re trying to get blood to flow to the zone of stasis. Cold water or ice can convert the zone of stasis to the zone of necrosis and turn a shallow second degree burn into a deep second degree burn, or a second degree burn into a third degree burn. Yes, ice will numb the pain. But you’d be far better off using an oral painkiller for that, or just telling the patient to hang in there and gut it out.

In the course of stopping the burning process remove all jewelery and clothing from the patient. Those items retain heat, or trap chemicals, or constrict the body when the obligate edema occurs. All bad things.

Protect the area with dry, sterile (if you have ‘em) non-adherent (if you have ‘em) dressings. Wrap the patient in a clean dry sheet. You want to limit airflow over the wound. If you have a burned hand, put dressings between the fingers. Don’t put on creams or lotions — they may retain heat, or they may make it difficult for the nice folks at the burn center to assess the injury, and may make it impossible for them to use certain treatments (e.g. tissue-engineered products). (And it’s going to hurt like a dog when they scrape the goo off, too.)

As in any injury, maintain the patient’s airway, breathing, and circulation. While you’re stripping off all his/her clothing, pay attention to other injuries that may be revealed. One thing that you can do: Check every pulse point that you know. Take your Sharpie Pen and mark the ones that have pulses. Later on, swelling may make those pulses vanish, but the nice doctors will thank you for finding them.

Burn patients are unable to maintain their own body temperature. The skin controls temperature; they’ve lost their skin. After you’ve wrapped them in that clean, dry sheet, wrap them in a couple of blankets. Get them somewhere warm. Turn up the heat. If you aren’t uncomfortable it isn’t warm enough.

Now some special kinds of burns:

1) Electrical burns. Typically the injury appears less severe than it really is, since the only obvious surface burns are at the points of contact, but the damage is done internally as the electricity goes from the source to ground. Along with the destruction of tissue in general there’s a special (and this is in common with crush injuries); when muscle is injured it releases potassium, with can cause fatal heart arrhythmias, and it releases myoglobin, which causes kidney damage. Fractures due to muscle contraction are also a real possibility. In an electrical burn assume that the patient’s back or neck is broken.

2) Circumferential burns. That is, they go all the way around either a limb or the chest. On a limb, a circumferential burn can act like a tourniquet and stop blood flow to the outer portions of the limb, resulting in tissue death. Around the chest, a circumferential burn can make it difficult or impossible for the patient to expand the chest and breathe. This is bad.

3) Smoke inhalation. I’ve mentioned this twice already, but it really is that important. Burns to the face or mouth, or a patient who’s spitting up black sooty phlegm, should make you think of smoke inhalation. But just because you don’t see those signs doesn’t mean the patient didn’t get a lethal lungful. Any time you have combustion you have carbon monoxide. Symptoms include nausea, vomiting, lightheadedness, and vague flu-like symptoms. Or, unconsciousness and death. The primary treatment is to get the patient away from the source of carbon monoxide. The half-life of carbon monoxide in the body when breathing normal air is 250 minutes. When breathing 100% oxygen, the half-life of carbon monoxide is forty to sixty minutes. So, oxygen if you have it. Cyanide — the treatment for cyanide is rapid transport to an emergency room that has the antidote available. Particulates: The treatment is even more IV fluid, because the surface area of the burn is lots bigger than it looks. Sulfur dioxide, ammonia, hydrogen chloride — all present in smoke — can create damage in the lungs that doesn’t become apparent for days after the exposure. The amount, the duration of the exposure… don’t assume you’re out of the woods just because the patient seems to be fine the next day. Anyone who’s been in or near a fire needs to be observed for a considerable time.

4) Chemical burns. Treat them like thermal burns, using large amounts of tepid water to stop the burning process. By “large” I do not mean “a liter or two” or even “a gallon or two.” I mean throw-them-in-the-shower or turn-a-garden-hose-on-them for twenty minutes. (Don’t attempt to neutralize acids or bases; the chemical reaction between the two may create heat, producing further injury, and anything strong enough to neutralize a strong acid or base is itself hazardous.) Remember, the water that you’re using to flush the injury is itself contaminated and may be hazardous to you. Be careful. Protect yourself first.

When you’re calling the hospital to tell them that you have a burn patient, the two things they want to know are a) the patient’s weight, and b) the percent of the body surface area that’s burned. One way of estimating body area is the Rule of Nines. (Another way is by estimating how many times the patient’s palm would cover the burn; the palm of the hand is about 1% of the patient’s skin surface.)

Bottom line: All burns are serious, regardless of their size. There is no such thing as a “minor” burn. Unlike other forms of trauma the body has few-to-no natural defense mechanisms. The defense mechanisms that it does have tend to worsen the injury. On the plus side, burns are seldom rapidly fatal. You have time to get the patient to a burn center.

The leading cause of death in burn patients is smoke inhalation. Even in the absence of surface burns any patient with smoke inhalation should be taken to the hospital, and may well be transported to a specialty burn center after evaluation.

A patient with burns means that the situation is dangerous. Be careful. Do not become a victim yourself.

Copyright © 2013 by James D. Macdonald

I am not a physician. I can neither diagnose nor prescribe. These posts are presented for entertainment purposes only. Nothing here is meant to be advice for your particular condition or situation.

Trauma and You, Part Five: Burns by James D. Macdonald is licensed under a Creative Commons Attribution-Noncommercial-Share Alike 3.0 License.

(Attribution URL: http://nielsenhayden.com/makinglight/archives/014819.html)

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