Monday, August 30, 2010

Protect Yourself from Hypothermia

(From the January-February, 2001 Newsletter)

It's time to start thinking about temperature; actually it's way, way past time to think about temperature. I am referring to water temperature. Although at this time of year you need to be very concerned about air temperature and wind chill, also.

The reason I said it's past time is because most people dress for the air temperature. All the major books on kayaking recommend that you dress for the water temperature. Why should I dress for 40° water when the air temperature is 65°? If I do that I'll be way too warm! "1 don't plan to go over anyway" .This is where the problem lies, unless paddlers plan specifically to practice rolls and wet exits, no one plans on getting wet. But even the "EXPERTS" get wet at one time or another when they didn't plan to.

So where does that leave you? Greater risk! The problem is, if you are not dressed for the water and you get dunked, you could get chilled. This very often leads to impending hypothermia. This is described as a person whose skin has become pale, numb and waxy. Muscles become tense and shivering may begin, but it can be overcome by activity. Fatigue and signs of weakness begin to show. There are variables that may contribute to the development of hypothermia. Age, health, nutrition, body size, exhaustion, exposure, duration of exposure, wind, temperature, wetness, medication and intoxicants may decrease heat production, increase heat loss, or interfere with thermostability.

Lets look at some reasons for heat loss that could lead to Hypothermia:
  • Conduction: Direct transfer of heat by contact with a cooler object -conduction of heat to the cooler object.
  • Convection: Cool air moving across the surface of the body -heat transferred to the cool air, warming it and cooling the body.
  • Radiation: Heat radiated outward from the warm body to the cooler environment.
  • Evaporation: The loss of heat through the process of removing water from the surface of the body through vaporization.
  • Respiration: Inspired air raised to body temperature and then exhaled.
Each of these causes of heat loss can play a large or small role in the development of hypothermia, depending on clothing, head cover, wind, weather, and whether you are wet or dry. Once hypothermia develops, the heat deficit is shared by two body compartments, the shell and the core. The shell consists of the outer 1.65 mm of skin and has an average area of 1.8 square meters. This constitutes approximately 10% of a 70-kg mass. The remainder of the body is the core. When we speak of "core temperature," it is thoracic, or critical core we are concerned with, mainly the area of the heart, lungs and brain.

Canoeing in the snow.


ICE WATER PADDLERS

Colleen and Doug Koss opted to take their canoe on the Sunday, January 7, 2001, winter trip down the south branch of the AuSable River. Kayakers on the trip were Ray Denno, Pat Nelson, Sally Marion and John Garner. Ray Denno had arranged for shuttle service from Paddle Brave Livery just outside Roscommon. The water was cold and black, offering a stark contrast against the white snow. The temperature was 14 F, and ice would build up on the paddle shafts as they were lifted out of the water and into the cold air. Except for the occasional cold fingers and toes, it was actually quite pleasant. 

Hypothermia symptoms take effect in three stages
  1. Mild Hypothermia - Bouts of uncontrolled shivering. Grogginess and muddled thinking. Movements become less coordinated. Coldness is creating some pain and discomfort.
  2. Moderate Hypothermia - Violent shivering or shivering that suddenly stops. Inability to think and pay attention confusion and apathy sets in. Slow, shallow breathing. Slow, weak pulse; speech becomes slow, vague and slurred; drowsiness and strange behavior may occur.
  3. Severe Hypothermia - Shivering stops, skin is cold, may be bluish-gray in color. Victim is very weak, may appear drunk, denies problem. Little or no apparent breathing, or loss of consciousness. Weak pulse or irregular or non-existent. Victim may be very rigid, and may appear dead.
Treatment for the Different Levels of Hypotheromia

  • Impending Hypothermia - Seek or build a shelter to get the person out of the cold, windy, wet environment. Start fire or cook stove to provide the victim with a hot drink (no alcohol, coffee or tea). Halt further heat loss by insulating the victim with extra dry clothes.
  • Mild Hypothermia - Remove or insulate the victim from the cold environment, keeping the head and neck covered. This prevents further heat loss and allows the body to re- warm itself. Provide the victim with a warm, sweetened drink (no alcohol, coffee or tea) and some high-energy food. Limited exercise may help to generate some internal heat, BUT it depletes energy reserves.
  • Moderate Hypothermia - Remove or insulate the victim from the cold environment, keeping the head and neck covered. Apply mild heat (comfortable to your elbow) to the head, neck, chest, armpits and groin of the victim. Use hot water bottles, wrapped Thermo-Pads, or warm moist towels. It is possible that you may have to continue this treatment for some time. Offer sips of warm, sweetened liquids (no alcohol, coffee or tea) if the victim is CONSCIOUS.
  • Severe Hypothermia - Place the victim in a pre-warmed sleeping bag with one or two other people. Skin to skin contact in the areas of the chest (ribs) and neck is effective. Exhale warm air near the victims nose and mouth, or introduce steam into the area. Try to keep the victim awake, ignore pleas of "leave me alone, I'm okay." The victim is in serious trouble, keep a close, continuous watch over the victim. Apply mild heat, with the aim of stopping temperature drop, not re-warming. If the victim has lost consciousness be very gentle, as by now the heart is extremely sensitive. Always assume the victim is revivable, do not give up. Check for pulse at the carotid artery. If, after two minutes you find no pulse, check on the other side of the neck for two minutes. If there is any breathing or pulse, no matter how faint, do not give CPR but keep very close watch for changes in vital signs. If no pulse is found, begin CPR immediately, stopping only when the heart begins to beat or the person applying CPR cannot carry on any longer without endangering himself. Medical help is imperative...hospitalization is needed.

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