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How to rehab firefighters in extreme heat, cold

Rehab is difficult and doubly so when the temperatures soar or plunge; here’s a look at how to handle those challenging days

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Heat-related illness is serious business, and firefighters are particularly at risk when temperatures hit the 90s and humidity hovers around 80 percent.

Photo/Joe Thomas of Greenbox Photography

This article first appeared on, sponsored by Masimo.

By EMS1 Staff

When we asked our readers in 2015 whether they’d rather fight fire in extreme heat or extreme cold, the responses were fairly divided. One thing we all agree on is that neither is our first choice. Yet, as one responder said, when the tone drops, you go.

Each extreme poses challenges for those charged with running the rehab sector.

For general rehab guidelines, NFPA is a sound starting place. NFPA 1584 Standard on the Rehabilitation Process for Members During Emergency Operations and Training Exercises can help fire departments establish their rehab process. The next edition of NFPA 1584 is open for public comment.

The standard requires these nine processes:

  • Relief from climatic conditions.
  • Rest and recovery.
  • Cooling or rewarming.
  • Rehydration.
  • Calorie and electrolyte replacement.
  • Medical monitoring.
  • EMS treatment in accordance with local protocol.
  • Member accountability.
  • Release from rehab.

Heat-related illness

Heat-related illness is serious business, and firefighters are particularly at risk when temperatures hit the 90s and humidity hovers around 80 percent. Hydration is critical, but it’s easy for firefighters to get overheated due to the combination of fireground conditions, PPE and summer heat. Robert Avsec advises that when prevention fails and heat-related illnesses set in, it is important to quickly recognize the signs and apply the proper treatment. Here’s a look at how to approach each level of illness.

To treat heat cramps:

  • Stop all activity; remove all items of the protective ensemble, particularly the protective hood; and sit quietly in a cool place.
  • Drink cool water, a sports drink or other drinks with no caffeine or alcohol.
  • Do not resume activity for a few hours after the cramps go away, as heat cramps can lead to heat exhaustion or heatstroke.
  • Get medical help if the cramps do not go away in one hour.

To treat heat exhaustion:

  • Perform the first two bulleted items above (stop, rest and hydrate).
  • Sit in front of a cooling fan or mister to help promote sweat evaporation and cool the body.

Heatstroke is a time-critical medical emergency. Get the firefighter to a shady or cool area and call for emergency medical assistance immediately. Until EMS arrives, do the following:

  • Cool the victim as quickly as possible with a cool bath or shower, a spray of cool water from a hose or by wrapping the victim in a cool, wet sheet.
  • Check body temperature often and continue cooling efforts until temperature drops to 102 F.
  • Do not give any fluids to the firefighter to drink because of the potential for airway compromise. If trained and authorized, administer intravenous fluids.

Cold-related injury

Providing firefighter rehab in the cold can be more difficult than in the heat. The freeze-thaw-freeze cycle is especially rough on the body, according to the Albert Einstein Medical Center.

Aside from slips and falls due to icy conditions, firefighters face several cold-related injuries. The most common and least serious of these is frostnip.

Frostnip is a mild cold injury most likely to occur in the distal extremities where there is decreased blood flow. Initially, there may be some mild pain, pale skin and numbness. There is no permanent tissue damage however, and the symptoms resolve quickly upon rewarming without any lasting damage.

Frostnip can be an indication of a more serious pending condition – frostbite. Frostbite represents actual damage to tissues and cells.

There are two mechanisms. The first is the formation of ice crystals both inside and outside of the cells. This can cause mechanical damage and cell death.

The second occurrence is similar to burn injury, where the blood vessels themselves are injured. This can result in increased swelling and even an increase in blood clots in the vessel. The combination of these two mechanisms can cause such severe damage that eventual amputation may be required.

The signs and symptoms of frostbite are initially the same as frostnip. However, the symptoms progress to also include worsening clumsiness of the affected area and loss of fine motor control.

The effects are deeper as well, and the affected skin may appear waxy and firm. Lastly, upon rewarming, the affected area develops more severe pain, burning or tingling and numbness. Blisters may develop, and swelling may be severe.

Is transport necessary?

How can we know if a firefighter just has mild frostnip and needs to warm up a bit or if he or she has developed frostbite and requires transport to the hospital? The reality is we can’t be completely sure.

In the emergency department, how the patient responds over a few hours will distinguish between the conditions, and will steer their disposition –home or stay.

In the field, start with the general assessment we should initiate with all firefighters – ask them how they feel. Do their feet feel a little numb, or do they actually hurt?

Are they able to walk normally, or are they stumbling because their feet won’t do what they want them to do? Are they unable to do simple tasks, such as change a nozzle or operate their SCBA?

If a firefighter has some of these more severe symptoms, do a more thorough physical exam. Look at and feel their hands or feet for the more serious signs mentioned above.

Also consider the time of exposure – frostbite is unlikely at an event of short duration. It is more common at those large, multi-alarm fires that last many hours or even days. If you have any doubts, recommend transport for a more complete exam in the hospital.

Frostbite treatment is simple: Protect the extremity with a well-padded splint. Do not rub or massage the affected area, as this can worsen the mechanical trauma. Do not initiate rewarming if there is any chance of a refreeze. Do not immerse in water or hold the extremity near the heater – there is a specific way to rewarm the frostbitten area that cannot be done in the field.

Cold immersion foot

A related condition that can occur when the temperatures are still above freezing is trench foot or cold immersion foot. The term “trench foot” comes from World War I and was seen among soldiers whose feet were wet and cold for a prolonged period. It most commonly occurs in conditions 32 to 59 F.

The cool temperature causes blood vessels to constrict as described above, but no ice crystals form. This constriction limits the amount of oxygen that is supplied to the tissues and cells of the foot.

The difference is that the skin is also affected by the moisture, which can cause exterior tissue breakdown. This permits the cold temperature to impact the nerves and blood vessels more directly, because the skin usually protects these structures.

The firefighter affected with cold immersion foot may feel few symptoms. Pain is rare. On exam, the foot is often pale and mottled. There is delayed capillary refill. Symptoms develop upon rewarming – the foot becomes swollen, red, warm and very painful.

Long-term effects are rare, and treatment is aimed at symptomatic relief. Interestingly, it is the rewarming that causes the pain and symptoms. As the foot is rewarmed, the oxygen demands increase, but the injured blood vessels cannot supply enough.

Keeping the extremity cool and then slowly warming over time is the preferred treatment. This is different from frostbite, which calls for rapid rewarming in the hospital.


Hypothermia, or a core body temperature of less than 95 F, is rare among emergency responders and not likely to be found among staff in the rehab sector as frequently as localized cold injury. However, if you encounter it, here are the levels of severity and treatment options.

Mild hypothermia (90 to 95 F) comes with an increase in respiratory rate and heart rate. Shivering occurs in an attempt to generate more body heat; speech and fine motor control may become slightly difficult. The blood vessels to the skin constrict in an attempt to conserve heat.

In moderate hypothermia (82 to 90 F), shivering stops and the patient begins to exhibit an altered mental status. The heart rate drops. If a 12-lead EKG is done, Osborn or “J-waves” may be noted.

Severe hypothermia (below 82 F) is the point where the patient is likely unconscious and unable to control his or her airway. These patients are at risk of having their heart rhythm degenerate into ventricular fibrillation.

Treating hypothermia

Treatment for hypothermic patients is supportive – meaning from a pre-hospital standpoint, we want to make sure things do not get worse and support the patient’s condition until we get to the hospital. This problem did not develop over 15 minutes, and we are not going to solve it in 15 minutes.

As always, start with the ABCs. Does the patient need to have an oral or nasal airway placed? If he or she is not breathing, start bag-valve-mask ventilations.

Check for a pulse, but understand that the heart rate may be very slow and difficult to detect. Do not delay care. If there are no signs of life, start CPR.

Prevention and recognition

Rehab is challenging in the best of weather and even more so when the temperatures soar or plunge. Plan ahead with your EMS medical director and EMS providers so your rehab sector is able to handle those challenging days. Educate your firefighters about self-care to prevent hypo- or hyperthermia and how to recognize the early signs in themselves and other firefighters.