To Do Today:
- PT – 45min run / strength – chest group / abs
- Review the Wilderness Medical Society Practice Guidelines for the Prevention and Treatment of Frostbite
Review this thread on SOCNET regarding feet and footwear.
- Review Carbon Monoxide Poisoning by Louise W. Kao, MD and Kristine A. Nañagas, MD
- Friday rules in effect at 1730.
COLD INJURIES IN COASTAL ENVIRONMENTS
Hypothermia, frostbite, and trench/immersion foot are the most popular cold injuries for students during the winter. Photokeratitis (snow blindness) will be covered sometime later as it usually occurs during sunny summer months. Please make sure to read the notes on carbon monoxide poisoning at the end of the post.
A common belief that extremely cold temperatures are needed for hypothermia to occur is not true as most cases occur when the temperature is between 30 and 50 degrees Fahrenheit.
Simply, hypothermia occurs when heat loss from the body exceeds the body’s ability to produce heat. Contributing factors include:
- Air temperature
- Ambient temperature
- Wind chill
- Wet clothing
- Cold water immersion
- Improper clothing.
- Alcohol intoxication, nicotine and drugs such as barbiturates and tranquilizers.
- Injuries. Those causing immobility or major bleeding, major burn and head trauma.
Signs and symptoms
The number one sign to look for is altered mental status; that is, the brain is literally getting cold. These signs might include confusion, slurred speech, strange behavior, irritability, impaired judgment, hallucinations, or fatigue.
As hypothermia worsens, victims will lose consciousness and eventually slip into a coma.
Shivering. Remember that shivering is a major way the body tries to warm itself early on, as it first begins to get cold. Shivering stops for two reasons:
- The body has warmed back up to a normal temperature range.
- The body has continued to cool. Below 95F shivering begins to decrease and by 90F it ceases completely.
Obviously, continued cooling is bad. So if a victim with whom you are working, who was shivering, stops shivering, you must determine if that is because he has warmed up or continued to cool.
A victim with severe hypothermia may actually appear to be quite dead, without breathing or a pulse. However, people who have been found this way have been successfully “brought back to life” with no permanent damage. The body of those who expire from hypothermia will exhibit a temporary warmth of the skin. So remember, you are not dead until you are warm and dead.
Prevention. Prevention is always better (and much easier) than treatment.
- Cold weather clothing must be properly warm and cared for.
- Keep your clothing as dry as possible.
- If your feet are cold, wear a hat. Up to 80% of the body’s heat can escape from the head.
- Avoid dehydration. Drink 6 – 8 quarts per day.
- Eat adequately.
- Avoid extreme fatigue and exhaustion.
- Increase levels of activity as the temperature drops. Do not remain stationary when the temperature is very low. If the tactical situation does not permit moving about, perform isometric exercises of successive muscles.
- Use the buddy system to check each other for signs/symptoms of hypothermia.
Treatment of Hypothermia
- Make the diagnosis.
- Prevent further heat loss.
- Remove the victim from the environment (i.e., into a shelter).
- Insulate the victim.
- Rewarm the victim by zipping two sleeping bags together. Pre-warm the bag by using the body heat of another. Place the victim in the bag with two stripped companions inside the bags on both sides of the victim (insert dirty jokes and snide remarks here).
- Medevac if possible.
Other Points to Remember
- Fluids. If the victim is mildly hypothermic, give hot/wets.
- If worse than mild, give him/her nothing by mouth.
- Avoid, if possible, excessive movement of the victim, as his/her heart may actually stop beating if it is jarred.
- Major Wounds. Apply first aid to major wounds first, before attempting to re-warm the victim. Re-warming a victim who has bled to death does little good.
- Never give alcohol to hypothermia victims.
- Even after you have started re-warming a victim, he/she must be constantly monitored. Don’t forget about the victim.
Frostbite is the actual freezing of tissues. When in a survival/SERE situation, rewarming a severe frostbitten area may not help. It is best to be vigilant of your situation prior to showing signs of frostbite as frostbite is a somewhat preventable injury, even in a desperate situation. It is critical, once frostbite has occurred, that you seek medical attention.
- Dress in layers. Keep comfortably cool. If you begin to become uncomfortable, add layers.
- Keep clothes dry. If clothing (especially socks and gloves) become wet, change them. This may mean you have to change sock 4-5 times a day.
- Dress properly. If the wind is blowing, wear the correct protective layer.
- Avoid dehydration. When dehydrated, the amount of blood available to warm your fingers and toes goes down, increasing the risk of frostbite.
- Try to avoid starvation. Remember – food is fuel – and the body uses that fuel to make heat.
Signs and Symptoms
- Ears, nose, fingers and toes are affected first.
- Areas will feel cold and may tingle leading to….
- Numbness which progresses to…
- Waxy appearance with skin stiff and unable to glide freely over a joint.
- Frostbite is classified into three different degrees: Frosting, Superficial Frostbite, and Deep Frostbite.
- Frosting will revert to normal after using the technique of body heat rewarming. Hold the affected area, skin to skin for 15 minutes. Rewarm face, nose, and ears with hands. Rewarm hands in armpits, groin or belly. Rewarm feet with mountain buddy’s armpits or belly.
- If affected area cannot be rewarmed in 15 minutes, Superficial Frostbite or Deep Frostbite is suspected. Do not attempt to further rewarm. Splint the affected area. Protect the affected area from further injury. Medevac as soon as possible. DO NOT RUB ANY COLD INJURY WITH SNOW. Do not massage the affected area. Do not rewarm with stove or fire: a burn injury may result. Loosen constricting clothing. Avoid tobacco products.
Any frostbite injury, regardless of severity, is treated the same – evacuate the casualty and re-warm in the rear. If not possible, find shelter and seek friendly indigenous medical care. If the tactical/survival situation prohibits evacuation, no consideration should be given to re-warming frostbite in the field. The reason is something-called freeze – thaw – re-freeze injury.
Freeze – Thaw – Re-freeze injury occurs when a frostbitten extremity is thawed out, then before it can heal (which takes weeks and maybe months) it freezes again. This has devastating effects and greatly worsens the initial injury.
In an extreme emergency it is better to walk out on a frostbitten foot than to warm it up and then have it freeze again. Also:
- Treat frozen extremities as fractures – carefully pad and splint.
- Treat frozen feet as litter cases.
- Prevent further freezing injury.
- Do not forget about hypothermia. Keep the victim warm and dry.
Once in the rear, a frostbitten extremity is re-warmed in a water bath, with the temperature maintained at 101F – 108F.
TRENCH FOOT / IMMERSION FOOT
Trench foot / immersion foot is a cold-wet injury to the feet or hands from prolonged (generally 7 – 10 hours) exposure to water at temperatures above freezing.
Signs and Symptoms. The major symptom will be pain. Trench foot is an extremely painful injury. Trench foot and frostbite are often very difficult to tell apart just from looking at it. Often they may both be present at the same time. Signs include:
- Red and purple mottled skin.
- Patches of white skin.
- Very wrinkled skin.
- Severe cases may leave gangrene and blisters.
- Lowered or even absent pulse.
- Trench foot is classified from mild to severe.
Prevention. Avoiding trench foot/immersion foot is aimed simply at preventing cold, wet and immobile feet (or hands).
- Keep feet warm and dry.
- Change socks at least once a day. Let your feet dry briefly during the change, and wipe out the inside of the boot. Sock changes may be required more often.
- Exercise. Constant exercising of the feet whenever the body is otherwise immobile will help the blood flow.
Treatment. All cases of trench foot must be evacuated. It cannot be treated effectively in the field.
While awaiting evacuation:
- The feet should be dried, warmed, and elevated.
- The pain is often severe, even though the injury may appear mild; it may require medication such as morphine.
- In the rear, the healing of trench foot usually takes at least two months, and may take almost a year. Severe cases may require amputation. Trench foot is not to be taken lightly.
NOTES ON CARBON MONOXIDE POISONING
Cold environments probably mean you will spend time inside some sort of shelter and have some sort of fire or other heat source. It is critical you have airflow and fresh air built into your setup. Carbon Monoxide is no joke.
Carbon Monoxide (CO) is a heavy, odorless, colorless, tasteless gas resulting from incomplete combustion of fossil fuels. CO kills through asphyxia even in the presence of adequate oxygen, because oxygen-transporting hemoglobin has a 210 times greater affinity for CO than for oxygen. What this means is that CO replaces and takes the place of the oxygen in the body causing Carbon Monoxide poisoning.
Signs/Symptoms. The signs and symptoms depend on the amount of CO the victim has inhaled. In mild cases, the victim may have only dizziness, headache, and confusion; severe cases can cause a deep coma. Sudden respiratory arrest may occur. The classic sign of CO poisoning is cherry-red lip color, but this is usually a very late and severe sign, actually the skin is normally found to be pale or blue.
CO poisoning should be suspected whenever a person in a poorly ventilated area suddenly collapses. Recognizing this condition may be difficult when all members of the party are affected.
Treatment. The first step is to immediately remove the victim from the contaminated area.
- Victims with mild CO poisoning who have not lost consciousness need fresh air and light duty for a minimum of four hours. If oxygen is available administer it. More severely affected victims may require rescue breathing.
- Fortunately, the lungs excrete CO within a few hours.
Prevention. Ensure there is adequate ventilation when utilizing a fire or other chemical/mechanical heat source near your shelter.