Ken Miller, MD, PhD

Most of our EMS education focuses on management of a victim of an injury or illness. However, here we’ll try to focus on things that can be done to prevent or treat injury or illness in firefighters during wildland firefighting operations. We’ll try to address the most likely threats encountered in wildland fire suppression and field living, but we’ll also take on some of the less common ones as well.

Out of county strike teams are structured to include paramedic capability. However, remote field operations in or out of county can expose personnel to injury and illness that may have to be managed in the field for some period of time by the basic EMT or paramedic. An injured firefighter may require transport off the fire line to the fire camp medical unit for further evaluation and treatment or may require immediate evacuation to a hospital. The location and capabilities of the medical unit, strategies for evacuation to hospitals by air or ground and communications to facilitate paramedic operations should all be outlined in the Incident Action Plan for each operational period.

You may be assigned to the position of Line EMT if your company is attached to the Medical Unit under the Logistics Branch. Line EMTs may be asked to operate independently of the Medical Unit on assignment to one or more strike teams to provide first aid, basic life support and injury and illness surveillance. This function is like a "medical safety officer" for the assigned strike teams to assure adequate hydration, rest, treatment and medical logistical support of the strike team mission. These type of operations may place you in situations not commonly encountered in everyday urban EMS. We’ll try to give you some information that will allow you to take care of yourself and your colleagues in hostile remote locations. Here are the areas we’ll cover:

Part I (September):

Traumatic Injuries

Heat-Related Illness and Sun Exposure

(heat stress, heat exhaustion, heatstroke)

Part II (October):

Bites and Stings

(bees, fire ants, anaphylaxis; bats, rabies; snakes; ticks, Lyme disease)

Contact Dermatitis and Allergy

(poison oak)

Base Camp Hygiene and Field Living

This is probably the group of problems that will be most familiar. The decisions you may face when evaluating an injured crewmember are: treat on the line and return to duty, evacuate to the Medical Unit for further evaluation and treatment, or evacuate directly to a hospital. Factors other than medical issues that may contribute to this decision process are the remoteness of operations, availability of means and route of evacuation, weather, criticality of the crew’s mission, and availability of replacement personnel and equipment. Unlike military missions, the concept of "acceptable casualties" is not embraced by the fire service. We fully expect to come back with every firefighter we left with and with them entirely intact. However firefighting is an inherently dangerous activity. Balancing safety with the need for life and property protection is a dynamic process. With the possible exception of the most extreme life threat situations, we undertake significant measures to prevent serious firefighter injuries. Minor injuries are however quite probable during intensive or prolonged operations. Wildland firefighting occurs on uneven and unfamiliar terrain during sometimes extreme and rapidly changing environmental conditions requiring concentration on multiple activities at one time. Long operational periods can result in fatigue, loss of concentration and inattention to hazards. This is a setup for injury.

Soft tissue injuries like abrasions, contusions, puncture wounds and lacerations along with sprains, strains, fractures and burns are the likely constellation of common traumatic injuries. Eye injuries too are quite predictable. In general, for any kind of open wound the key treatment in field management is irrigation. Removal of debris from the wound will reduce the risk of infection later, especially if evacuation off the line is momentarily impossible or will be delayed. Once irrigated a durable dressing will protect the wound until evacuation or further evaluation is possible. Ideally the irrigation solution should be sterile and isotonic, like sterile saline. But carrying solutions takes space and adds weight to daypacks. So if this is not available any potable water source will be adequate. On your next trip to a drugstore look for your favorite durable Band-Aids and any small prepackaged irrigation solution to pack along. Wound closure can be delayed up to 12 hours usually. Beyond that the risk if infection seems to go up, so a wound older than 12 hours may be explored, irrigated again, packed with a sterile material and rechecked daily. If no infection is evident after 2 to 3 days then the wound can be closed. Tetanus booster immunization should be given every 5 years. These wounds will likely be tetanus prone.

Sprains can be minor or serious. These ligament injuries can look a lot like fractures when enough damage is done to the ligament. There can be swelling, pain, tenderness, ecchymosis, deformity and loss of function. Except for minor sprains they will probably need further evaluation. Effective field treatment though for sprains (or fractures if that is what it turns out to be) is just like on the playing field: rest (stay off of it), ice (if available), compression (with immobilization) and elevation ("RICE"). An ice compression dressing can reduce the amount of swelling and pain that will develop and if it turns out only to be a sprain may increase the chances of return to duty if that is what is desired.

Minor burns can occur at gaps in nomex, like the wrist, neck and face. Of course serious burns will require immediate evacuation. The closest burn center should have been identified in the Medical Plan of the IAP along with a helicopter tasked for any immediate medical evacuation mission and the means to contact them. Airway protection, IV access and pain control would be priorities if field time and resources allow. Minor burns will probably be superficial (first degree) or partial thickness (second degree). Both will look similar in the immediate postburn period. Ice, when available, is helpful to reduce pain followed by irrigation and a durable dressing. If the burn is partial thickness and blisters develop it is generally best to leave them intact if possible. They form a natural protection to the underlying burn wound and reduce the risk of infection. If the location of the burn makes blister protection impossible, then remove the dead blister material and treat it like an open wound with irrigation and durable dressing. Later an antibacterial cream or ointment can be applied to the dressing when it is changed. Bacitracin and Silvadene are the ones most commonly used. Large blisters will have to be completely debrided back to intact skin so they should be evaluated in the Medical Unit. Leaving behind blister material is a setup for infection later.

Speaking of blisters, the other source for blisters is boot friction. Friction blisters are best managed by prevention. Make sure your socks and boots fit well. During rest periods take off boots and socks and dry and massage your feet when practical. Extra dry socks can be packed in too. At the first sign of irritation, like pain and redness before blister formation, place a patch of moleskin over the area. Once a blister has formed it’s less satisfactory to manage. Some moleskin packs come with formed rings to place around small blisters to protect them from further injury. Unroofing a blister and covering it with a durable Band-Aid or moleskin may be necessary but now it will need to be checked and cleaned several times a day to prevent infection. As trivial as it sounds foot care is essential. Wash and dry your feet while in fire camp between operational periods. Keep extra socks in your out of county bag.

Treating minor pain in the field is possible with over the counter drugs like ibuprofen, Tylenol (acetaminophen) or Aspirin. No one drug is right for everybody. There are medical conditions that can limit the use of any of these analgesics. Find one that is safe and effective for you and pack a few doses with you. Be careful using any analgesic that contains a drug that causes drowsiness. Loss of concentration on the fireground is dangerous. If absolutely necessary these analgesics should only be used when returning to fire camp long before the next operational period for your crew.

Eye injuries are a predictable injury during the early phases of wildland firefighting due to airborne particulates and wind. The trouble is that a foreign body sensation in the eye may be just that or a corneal abrasion or both. Usually corneal abrasions that result from foreign bodies that are not accelerated into the eye, like hammering or power tools, result from rubbing the eye with the foreign body still there. Eye protection should prevent these injuries. At the first sensation of a foreign body in the eye try to lift the lid a little and let the action of tears help to flush it out. If this is unsuccessful it will be necessary to irrigate the eye. Water is fine because it will be available. IV solutions are good and the tubing helps to aim the stream but they may not be immediately available on the fireground. Early irrigation will almost always remove a surface foreign body and prevent a subsequent corneal abrasion. If eye pain or a feeling of a retained foreign body persists then that eye should be evaluated in the Medical Unit or a hospital emergency department. Corneal abrasions are not necessarily serious but may require and eye patch and topical antibacterial to reduce pain, allow healing and reduce the risk of infection and corneal ulceration. An eye patch removes stereoscopic vision and will not allow a return to duty on the fireline.

Another very likely problem in wildland firefighting is heat-related illness. The body will accumulate heat from two sources. One source is convected and radiant heat from flame, heated earth and sun. The other is heat generated by muscular activity involved in fire suppression. Together the body can begin to store more heat than it can dissipate by sweat evaporation, conduction and convection. By far the most important mechanism of heat dissipation is sweat evaporation. And about 50% of sweat production is from the face and scalp. Primary prevention of heat illness is as important as recognition and treatment.

Clearly we are at a disadvantage in preventing heat illness. Fire suppression operations and protective gear place us in proximity to heat sources and reduce effectiveness of heat dissipation. One preventive measure is to be sure to hydrate well before leaving fire camp for the operational period’s mission. In addition, regular hydration during work is essential. People who have studied heat illness in athletes conclude that voluntary hydration, or drinking only when thirsty, is not sufficient to replace fluid losses. So, during every rest period or whenever practical drink water, 8-12oz. every 20-30 minutes is recommended for heavy physical activity. Water will generally be sufficient. Sport drinks and other salt and carbohydrate additives are reasonable with a few considerations. It is generally recommended that the sugar or carbohydrate content be less than 6%. Higher concentrations slow gastric emptying and can give a feeling of fullness or even nausea. These sensations will lead to reduced fluid intake, further complicating dehydration. Sodas with their high sugar content and carbonation are not good for rehydration. Sweat is hypotonic so you are loosing more water than salts. Meals will replace the salts lost. Chilled drinks also increase gastric emptying, but they are not always available. Another preventive measure is to remove headgear like the flash hood, bandanna and helmet during rest periods if it is safe to do so. The head and face dissipate heat proportionately greater than other parts of the body. Toweling off the head and face will help cool the body down. Acclimatization to heat does occur but takes up to 7-10 days. Long deployments may allow enough time for this to happen. Once acclimatized you will sweat sooner with physical activity and sweat in larger volume. Sweat becomes more hypotonic. This helps keep body core temperature down but increases hydration needs. Predicting the risk of heat illness is possible by calculating the Wet Bulb Globe Temperature Index (WBGT). The WBGT Index is calculated from the ambient temperature, wet bulb temperature which is determined by humidity, and globe temperature which is determined by radiant heat. This value may be available from the fire weather specialist and can be used to judge work-rest cycles.

Water Intake and Work-Rest Cycle

*Not to exceed 1.5 quarts/hour or 12 quarts/day.

1 quart approximately equals 1 liter.

Recognition and treatment of heat illness is sometimes confusing because the syndromes represent a continuum of disease. Textbooks tend to list specific symptoms and signs without clarifying that one syndrome can progress to another without abrupt changes in appearance. Heat stress is the mild syndrome of weakness, dizziness, fatigue, and maybe mild nausea that occurs early from heat accumulation and inadequate hydration, rest or cooling. Body temperature remains normal. It usually responds to rest, removal from exposure as much as possible and rehydration. Return to duty is likely. Heat exhaustion and heat cramps develop next if early heat stress is not addressed. Exertional heat exhaustion presents with headache, dizziness, drowsiness, confusion, chills, and possibly syncope. Probably the first indication that heat stress in progressing to something more serious is subtle change in mentation. The person will remain conscious and alert but may be slightly confused or show some impairment of judgment. Body temperature may be near normal early in heat exhaustion but may also be elevated. Temperatures below 39C (102.2F) are likely in heat exhaustion. Heat cramps may occur with or independent of heat exhaustion. They usually follow several hours of heavy physical activity, heavy sweating and water rehydration. Muscle cooling at rest may also bring on heat cramps. Heat cramps respond to rest and salt rehydration, either using a sport drink or by eating food. Treating heat exhaustion requires removal from exposure, probably evacuation to the medical unit if possible, cooling measures, oral or intravenous rehydration and rest. Rehydration should be at a rate of 1-2 liters over 2-4 hours. If nausea limits oral rehydration then IV saline may be necessary. The distinction between recovery from heat stress and from heat exhaustion is that it will take more time to recover from heat exhaustion. It may take up to 24 hours to recover. A return to duty decision will require more careful judgment. The most effective method of active cooling is removal of head and chest gear and moist toweling and fanning of the head and torso.

Exertional heatstroke is the next transition in heat illness. Body temperature regulation begins to fail. Temperature of 41C (105.8F) or greater is usually used to define heatstroke. This syndrome is the version of heatstroke most likely to occur on the fireground. Both heat storage from the environment and heat generation from muscular activity contribute to heat accumulation. The important point to make here is that there can still be profuse sweating during the transition from exertional heat exhaustion to exertional heatstroke. Mental status continues to decline and will be clearly abnormal now. Seizures are possible as temperature rises. This is an emergency and will require evacuation to a hospital either directly from the fireline or from the Medical Unit, whichever is more logistically appropriate. The key field intervention is aggressive external cooling. Like before, toweling off with water and fanning the head, face and torso is both practical and effective. If available, ice packs can be placed over the blood vessels in the neck, axillae (armpits) and groin. By itself this is less effective be is additive to evaporative cooling measures. When available oxygen should be give by nonrebreather mask and IV started for rapid IV saline rehydration. If seizures occur IV diazepam (Valium) can be given. The goal of cooling measures is to lower the body temperature below 39C (102.2F) within 30 minutes.

What makes the recognition of heatstroke confusing is that it can occur in two forms. Exertional heatstroke is the form most likely to be encountered on the fireground. It is characterized by marked body temperature elevation, altered mental status, hot wet skin and possibly seizures and hypotension. Classic heatstroke is the version described with hot dry skin, along with altered mental status, seizures and hypotension. The difference is the mechanism of heat exposure and population of people exposed. Exertional heatstroke takes hours of exposure and exertion to develop. Classic heatstroke takes hours to days to develop and results from ongoing exposure to hot ambient temperatures. Exertion is not an element of classic heatstroke. Usually the elderly, poor, malnourished, substance addicted and chronically ill are victims of classic heatstroke. Urban heatwaves (like the one occurring now in the Midwest and the 1995 Chicago heatwave that killed up to 700 persons) are a good example as is passive hyperthermia in children and pets left in exposed unventilated vehicles. Confined space operations in proximity to a radiant heat source also can cause classic heatstroke. Treatment is the same, but don’t assume that the diagnosis of heatstroke requires the absense of sweating. Another interesting and important observation is that vulnerability to heat exhaustion and heatstroke depends in part upon cumulative heat stress. In other words, sequential hot days even with relatively cooler nights in between increases the risk of heat exhaustion and heatstroke. So vigilance should increase on longer wildland firefighting deployments.

One last thought on heat-related illnesses. Since sweating is such an important means of body heat dissipation, any medication that reduces sweating has the potential to accelerate the onset of heat exhaustion or heatstroke. Medicines with anticholinergic properties will reduce sweating. The class of drugs that is likely to be used during wildland firefighting with this property is the antihistamines. Runny nose and allergies are common nuisance symptoms in outdoor activities. If you choose to use an antihistamine to control these symptoms keep in mind that all over the counter antihistamines are both sedating and have anticholinergic effects. Mild sedation alone can be a hazard. But reduced sweating may predispose to heat stress and other heat-related illnesses. If necessary the prescription less-sedating antihistamines may be a compromise but they too have anticholinergic effects. Overall, decongestants may be a safer choice for upper respiratory allergies than antihistamines for this application.

Sun exposure is less of a problem since protective gear limits skin exposure to the sun. Facial exposure is probably the most likely place for sunburn. Cooling off during rest periods adds some potential for sun exposure. Firefighting at altitude is not common in southern California, but on out of county mutual aid deployments keep in mind that for every 1000 feet of altitude ultraviolet radiation exposure increases about 4% since there is less atmosphere to absorb it. Sun protection at altitude becomes more important. Clouds reduce but do not eliminate UV penetration. As little as 10% and as much as 80% of UV radiation can be absorbed by clouds. Some UV radiation can be reflected by sand, metal, concrete or water. Wind exposure seems to worsen the skin injury from sun exposure. Prevention is by application of sunscreens. There are two types of sunscreens. Chemical sunscreens absorb UV radiation and physical sunscreens reflect or scatter it. The Sun Protection Factor (SPF) is a ratio of the amount of time it takes for protected skin to get red compared to unprotected skin. Since skin types vary in their response to sun exposure it is generally recommended that a sunscreen with an SPF of at least 15 be used. Beside SPF, the other sunscreen property that is important to protection is substantivity. This is a qualitative assessment of how well the sunscreen stands up to sweating or getting wet. Since advertising can be deceiving, it is best to try a few brands to see which ones seem to last when wet. Be sure to apply sunscreen liberally. A product labeled at SPF 15 will protect to a much lesser degree if applied too thin. Lip balm with sunscreen is also helpful to prevent cracked, dried, painful lips from sun, wind and heat exposure.

In addition to issued protective gear and water here are a few suggestions to pack with you for comfort. Most of these items can be purchased in small unit packages to minimize space a weight. They should become available from the Medical Unit as the incident command structure builds.

Insect repellent (DEET)

Sunscreen

Lip balm

Bacitracin ointment

Poison oak protectant

Eye & wound irrigation solution

Decongestant

Ibuprofen, Tylenol or Aspirin

Gum or throat lozenges

Personal medications

Band-Aids

Moleskin

Food bars

Towel

Extra socks

We’ll discuss more of these items in Part II and take on the problems of poison oak dermatitis, insect stings, allergy, anaphylaxis, snake bites, bats and rabies, ticks and Lyme disease.

1. Kaplan LA, Suntan, Sunburn and Sun Protection, Journal of Wilderness Medicine 1992, 3:173-196.

2. Hubbard RW, Gaffin SL, Squire DL, Heat-Related Illnesses, In Auerbach PS, Wilderness Medicine, third edition, Mosby, 1995, pp. 167-212.

3. Davis KM, Mutch RW, Wildland Fires: Dangers and Survival, In Auerbach PS, Wilderness Medicine, third edition, Mosby, 1995, pp. 213-242.

4. Friedlander J, Lowe NJ, Exposure to Radiation from the Sun, In Auerbach PS, Wilderness Medicine, third edition, Mosby, 1995, pp. 291-311.

5. Morris Jr. JA, Swiontkowski MF, Herrmann HJ, Wilderness Trauma Emergencies, In Auerbach PS, Wilderness Medicine, third edition, Mosby, 1995, pp. 312-354.

6. DeLorenzo RA, Porter RS, Tactical Environmental and Preventive Medicine, In Tactical Emergency Medicine, Brady, 1999, pp. 252-254.