Tag Archives: Hypothermia

Hypothermia

SEAL Qualification Training in Kodiak

Photo by PO2 Erika Manzano

10/06/14
To Do Today:


1-10-1

1-10-1 is a simple way to remember the first three phases of cold water immersion leading to hypothermia and the approximate time each phase takes:

1 – Cold Shock. An initial deep and sudden Gasp followed by hyperventilation that can be as much as 600-1000% greater than normal breathing. You must keep your airway clear or run the risk of drowning. Cold Shock will pass in about 1 minute. During that time concentrate on avoiding panic and getting control of your breathing. Wearing a lifejacket during this phase is critically important to keep you afloat and breathing.

10 – Cold Incapacitation. Over approximately the next 10 minutes you will lose the effective use of your fingers, arms and legs for any meaningful movement. Concentrate on self rescue initially, and if that isn’t possible, prepare to have a way to keep your airway clear to wait for rescue. Swim failure will occur within these critical minutes and if you are in the water without a lifejacket, drowning will likely occur.

1 – Hypothermia. Even in ice water it could take approximately 1 hour before becoming unconscious due to Hypothermia. If you understand the aspects of hypothermia, techniques of how to delay it, self rescue and calling for help, your chances of survival and rescue will be dramatically increased.

Hypothermia

Without floatation, you will not die from hypothermia; you will drown first. The chilling effects of cold air and wind but water poses the greatest threat because it transfers heat 25 times faster than air. Depending on the water’s temperature, a victim can succumb to hypothermia within a few minutes.

The body’s sudden contact with cold water can also set off a body reaction known as the mammalian diving reflex. This reflex can greatly increase survival time (especially for women and children) in or under cold water. The mammalian diving reflex shuts off blood circulation, except for the flow between the heart, lungs, and brain. The small amount of oxygen left in the blood and lungs is saved for the body’s vital organs. This reflex has allowed people to survive being under cold water for an extended period of time. Therefore, a cold water drowning victim should be treated as if still alive even though the victim is not breathing, has no pulse, and may appear dead. WARNING: If the victim has no pulse and is not breathing, administer CPR immediately. If the victim does have a pulse but is not breathing, give rescue breathing only. If the victim has a pulse and is breathing, DO NOT give CPR—CPR could prove fatal. Continue first aid until medical help arrives. Check for a pulse for at least 45 seconds.

Symptoms

Once the body’s core temperature drops, the victim will show one or more of the following symptoms:

  • Violent and uncontrollable shivering as the body tries to warm itself.
  • Slow or slurred speech.
  • Disorientation or poor coordination.
  • Loss of skin color.
  • Blue and pinched lips.
  • A slowing or stopping of shivering that progresses into a rigid torso and limbs.

Survival Time

A hypothermia victim’s survival depends on the water’s temperature and the time spent in the water. A small body build cools faster than a large build. Children cool faster than adults.

Cold Water ExposureTo increase your chance of survival in the water, utilize the HELP position, or huddle position in a group, shown below:

huddle-300x240Extra clothing and inactivity (remaining motionless in the water) can also increase your survival
time.

Treatment

A hypothermia victim must be warmed to prevent further heat loss; therefore, treatment should begin as soon as possible. Consciousness of the victim determines the treatment that should be pursued. The following general treatment procedures are recommended:

  • If the victim is conscious, give the victim warm fluids. Give candy or sweetened foods to a victim who is able to eat.
  • If the victim is unconscious, place him on his back with his head tilted back to ensure an open airway.
  • DO NOT massage the victim. Massage can break blood vessels and create swelling, internal pressure, and blocked blood circulation.
  • DO NOT give alcohol to the victim. Alcohol lowers the victim’s body temperature.
  • Shock is a possibility, treat accordingly.
  • Seek medical help immediately/as soon as possible.

If medical help is not immediately available and can be removed from the water:

  • Get the victim into shelter.
  • Remove the victim’s wet clothing.
  • Put the victim in dry clothing.
  • Place the victim in a sleeping bag if one is available. It may be necessary to place another person in the sleeping bag with the victim.
  • Place as much insulation as possible between the victim and the ground.
  • Use hot water bottles, electric blankets, or blankets heated in an oven or by a campfire to warm the victim’s neck, groin, and the sides of the chest. CAUTION: DO NOT apply heat to extremities.

Treatment for mild hypothermia

If there is no way to get to a medical facility within 30 minutes, a mildly hypothermic person should be rewarmed as soon as possible. Shivering is a very effective process especially when well insulated. Shivering should be fueled by calorie replacement with fluids containing sugars. The sugar content is actually more important than the heat in warm liquids. Make sure that the person is capable of ingesting liquids without aspirating. Alcohol and tobacco use should not be permitted because they constrict blood flow.

External heat can be applied to high heat transfer areas such as the underarms and sides of the chest. Active heating of the skin is beneficial as it increases comfort, preserves energy stores and reduces cardiovascular stress

Light exercise such as walking produces heat but should only be attempted after a mildly hypothermic person is dry, has had calorie replacement and has been stable for at least 30 minutes. A warm shower or bath may be tolerated by an individual that is alert and mobile. However, this could be fatal to a moderate to severely hypothermic person and should be avoided in this case.

Treatment for moderate to severe hypothermia

This is a serious medical emergency requiring proper handling and treatment and in severe cases, immediate transport to a medical facility. There are some specific things you can do to help stabilize the individual prior to the arrival of proper medical attention.

Great care must be taken in handling a moderate or severely hypothermic person. Extraction from the water must be as gentle as possible to avoid precipitating ventricular fibrillation. Arms, hands, feet and legs should not be rubbed or manipulated. The person should be placed in a horizontal position and wet clothing should be gently removed and the body insulated as best as possible using dry blankets, clothing or other protective materials. If shelter is available, keep the person protected from the elements and insulated from the cold ground or snow using sleeping bags, clothing, back packs or even evergreen boughs.

If vital signs are present, the person should be rewarmed as previously described but not allowed to sit or stand until rewarmed. Under no circumstances should the person be placed in a warm shower or bath, no oral fluids or food should be given and no attempts should be made to rewarm with exercise, including walking.

In any hypothermic individual, core body temperature continues to decrease after rescue. It is called ‘afterdrop’ and may last many hours in a moderate to severely hypothermic person when no shivering is present and metabolic heat production may be only 50 percent of normal. Even gradual warming of the heart will help avoid cardiac arrest and ventricular fibrillation.


Information contained on this website is for general information and educational purposes only. Please refer to our Disclaimer and Terms and Conditions before attempting any technique described herein.

Cold Water

hypothermia-huddle

Courtesy US Coast Guard

09/30/14
To Do Today:

  • PT – Cardio – 1hr Swim // Strength – Chest and Biceps
  • Practice the floatation methods described below in a pool until mastered

Avoiding Heat Loss in Cold Water

The rate of heat exchange in water is about 25 times greater than it is in air of the same  temperature. When you are immersed in cold water, hypothermia occurs rapidly due to the  decreased insulating quality of wet clothing and as a result of water displacing the layer of still  air that normally surrounds the body.

Survival-TableYou also lose about 50 percent of your body heat through your head; therefore, keep your head out of the water. Other areas of high heat loss are the neck, the armpits/sides, and the groin:

heatloss1In cold water, DO NOT SWIM TO STAY WARM. Swimming, even with a slow and steady stroke, produces a lot of heat that is lost in the water. The heat loss can produce hypothermia that slows body functions and can result in serious injury or death. Remaining motionless conserves body heat three times longer than swimming. SWIM only if you have flotation and the shoreline is visible.

Individual Protection From Cold Water

If you are equipped with a life preserver, assume the Heat Escape Lessening Posture (known as  the HELP position) to slow heat loss and to protect major blood vessels near the body’s surface.  These areas lack insulating fat and are vulnerable to the chilling effects of cold water.

heatloss2To assume the HELP position:

  • Tuck your chin down tightly to cover your throat.
  • Draw your legs up in a fetal position to protect the groin.
  • Place your arms across your chest, tuck your hands into your armpits.
  • Wear some type of head covering (e.g., stowed cover, towel, handkerchief) to lessen heat loss through the scalp if head covering is available.

Group Protection From the Cold

If three or more swimmers are in the water and are equipped with life preservers, they should wedge tightly together and lock arms to form a circle known as a huddle position.

heatloss3This position protects vulnerable areas from heat loss. A casualty who is suffering from the effects of the cold can be placed within the huddle to be surrounded by warmer water. If in the water for a  prolonged period, it is recommended that everyone be rotated inside the huddle to maintain or re-warm each person’s internal core temperature. If there are more than five swimmers, they  should make clusters of huddle positions. Contact with other swimmers provides survival advantages:

  • Creates a larger target for search and rescue aircraft
  • Provides additional warmth in cold water
  • Improves morale
  • Establishes/re-establishes leadership
  • Reduces shock and panic
  • Provides opportunities to administer first aid
  • Supports the exhausted

Information contained on this website is for general information and educational purposes only. Please refer to our Disclaimer and Terms and Conditions before attempting any technique described herein.

Coldest

freezing-cold-2

09/19/14
To Do Today:


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.

HYPOTHERMIA

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.
  • Exhaustion.
  • 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

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.

Treatment

  • 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.
  • Swelling.
  • 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.