Tactical Medicine: Dealing With Weather Exposure in the Field

With some training and preparation, a field medic can prevent serious conditions such as heat stroke and hypothermia.

Tactical Medicine

Tactical Medicine is an introduction to providing critical medical care when lives hang in the balance — both yours and your patients'. Learn the three stages of tactical medicine, the vital priorities of administering first aid under fire, the realities of setting up an efficient triage system, the must-have equipment and supplies for a tactical medical kit and more.

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Learning about in-the-field and tactical medicine could help you save a life. Tactical Medicine (Paladin Press, 2012) can help you learn about preparing for emergency care. In this excerpt, writer and former military medic Ian McDevitt explains temperature-related emergencies, symptoms of hypothermia and other conditions, plus their treatment.    

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More than likely, the most serious problems the tactical medic will face on a regular basis are heat- and cold-related emergencies.

Environmental emergencies are very common during training and while conducting actual operations and have a direct effect on mission success. Therefore the medic must always be aware of the weather and its effect on the team members.

The common point of both heat- and cold-related problems is that they are disease processes. By this I mean that they consist of a logical progression of signs and symptoms that, if recognized, can be reversed by the team medic before they progress to something more serious.

Humans create excess heat through exertion. Heat from muscle activity builds up in the blood, and our body’s core temperature rises. The body’s own preventative measures take over by stimulating the sweat glands and sending blood to the skin to cool off. Problems develop when the body is overloaded or unprepared to deal with the hot environment.

How to Prevent Heat Exhaustion

Heat exhaustion is caused by an even greater deficit of electrolytes and fluids in the body. Heat exhaustion by itself may not be life-threatening, but it will progress to heat stroke if not treated immediately. This condition may give advanced warning with the onset of fatigue and heat cramps. Other symptoms may include pale, moist skin; a “cold sweat” feeling; nausea; and lightheadedness. Treatment for heat exhaustion involves getting the patient to a shaded area, loosening his clothes, and getting his gear off. Provide rest and water. Apply cool packs to the areas under the armpits, behind the knees, and around the neck. I recommend starting an IV line of normal saline or Ringer’s Lactate to replace lost electrolytes.

Heat Stroke

Heat stroke is the most life-threatening of the three stages of heat stress. It basically can be described as the body generating heat faster than it can get rid of it. The cooling mechanism fails and the body’s core temperature rises rapidly. Once heat stroke sets in, the medic has as little as 30 minutes to act before the patient may die. The patient may have hot, red, and (sometimes) dry skin and a strong, rapid pulse. Body temperature is usually above 106°F.Treatment revolves around rapidly cooling the patient and managing his airway if he becomes unconscious and cannot support the airway on his own. I recommend at least one large-bore IV of a crystalloid like saline or Ringer’s Lactate to replace electrolytes, and get the patient to a hospital if possible.

Heat Cramps

Heat cramps develop when a team member is sweating heavily and not replacing enough fluids and electrolytes. He may develop cramps or muscle spasms in the hands, feet, stomach area, or, quite commonly, in the long muscles of the legs.

Treatment consists of moving the patient to a shaded area and giving him water. Stretch the muscle and rest it. Don’t massage it, as it may cause strains or even sprains.

Prevention of heat-related injuries involves diligence on the part of the tactical medic. You must be aware and able to recognize what’s going on with fellow team members. Use the buddy system to keep everyone in check. Prior knowledge of all your team members’ medical histories will allow you to keep tabs on those who have been heat casualties in the past, as they are more susceptible to become heat casualties again.

Cold-Weather Safety

Operations in cold weather entail their own set of unique problems. It is the medic’s job to ensure that each team member is prepared to battle the cold with proper dress and knowledge of the signs and symptoms that signal cold-related injuries. Providing sufficient food and water for the team also helps fight off these problems.


Frostbite, or freezing of the skin, normally affects the hands, feet, ears, and nose. It involves those areas that the body considers least essential in its battle to maintain heat at its core. It can be superficial or deep, depending on the temperature and the amount of exposure. The skin will appear bluish white and waxy and will more than likely be hard to the touch. Ideally, with proper education of team members in what to look for, most cases of frostbite will be superficial and there will be no permanent nerve damage. Treatment involves rapid rewarming. You want to do this rapidly because damage to the skin and nerves is done during the freezing and thawing process. It is key that you prevent the injured area from refreezing.

If possible, place the injured area in a bath of warm water approximately 104°F. Analgesics may need to be administered, as this will be a painful episode for the patient. Field-expedient methods of warming the extremity include placing it skin-to-skin under an armpit or on the chest of another team member. I have even heard of urinating on the affected body part, but I have never tried it.

Immersion Foot

Immersion foot is a very real emergency to the tactical team member because it directly affects mobility, and that affects the unit as a whole. The direct cause of immersion foot is prolonged exposure of the feet to several hours or even days of wet and cold conditions. The underlying cause is a lack of knowledge of proper foot care among the team.

With immersion foot, the patient’s feet become red, then pale and swollen. He may complain of a “pins and needles” sensation or even numbness. The medic’s job is to get the patient to dry his feet off, elevate them to reduce pain and swelling, and warm them up. There is no need to thaw them out because there will be no freezing of tissue.


Hypothermia is defined as a drop in the body’s temperature below 98.6°F. It needs to be emphasized that hypothermia is a true mission-ending problem. It routinely kills even experienced outdoorsmen in the backcountry. Several years ago at the U.S. Army Ranger School, a handful of students died from hypothermia. Early detection is the key to preventing this condition from becoming life-threatening.

The human body loses heat to the environment through four main routes:

1. Conduction—the loss of heat through contact with objects colder than the body.
2. Convection—the loss of heat through wind chill.
3. Evaporation—the loss of heat due to sweating.
4. Radiation—the loss of heat through the body actually radiating heat off the skin and into the environment.

The key to treating hypothermia is to not get it. Avoidance through proper monitoring of team members (both by the medic and through the buddy system) and early detection is imperative. Education plays a big part—team members should be instructed on the signs and symptoms of hypothermia and notify the medic if a problem arises in themselves or a fellow team member. These signs and symptoms are:

Mildly Hypothermic Patient 

1. Shivering
2. Urinating frequently
3. Stumbling/lagging behind
4. Loss of fine motor function

Severely Hypothermic Patient 

1. Inability to walk in a straight line
2. Lack of shivering
3. Slurred speech
4. Decrease in level of consciousness

The steps to take when hypothermia is suspected are straightforward:

1. Decrease heat loss. Remove wet clothes, get the patient out of the wind, move to a sheltered area.
2. Increase heat production. Start a fire if you are able to. Get warm liquids down the patient if his level of consciousness supports it. If he is able to eat, get some food into him to increase heat production. Put him in a vehicle with the heat on if available. Get an IV line established and some fluid into the patient, as dehydration goes hand in hand with hypothermia. Manage the airway if required and apply a cardiac monitor if available and the severity warrants it.

It needs to be stressed again that both heat- and cold-related emergencies are prevented through:

1. Strong leadership
2. Constant monitoring
3. Use of the buddy system
4. Rapid, definitive treatment
5. A properly stocked medical kit

This excerpt has been reprinted with permission from Tactical Medicine by Ian McDevitt and published by Paladin Press, 2012. Buy this book in our store: Tactical Medicine.