Friday, May 21, 2010
by Brent McNamee
Surviving Cold Water Immersion
Even though it may be t-shirt weather and the air is warm, the water can still be
very cold. Because the majority of us do not participate in cold water activities,
we are unaware of how our bodies react in early and late season conditions. On average,
200 people die each year from cold water immersion. If you're heading out on the
water this winter, or even doing some work around the shoreline, there are a few
things that you should know about Cold Water Immersion and Hypothermia. Always wear
a PFD (Personal Floatation Device) or life jacket when boating in early or late
season weather. There is also a wide selection of Hypothermia clothing available.
The Huddle Technique
It is important to keep your head out of the water. A large percentage of your body
heat is lost through your head, so it is critical to keep dry. Cold temperatures
significantly decrease your physical ability. Swimming will be more difficult and
you will not be able to swim as far.
Always try to remove yourself from the cold water if you happen to fall in. If you
have fallen from a boat, attempt to climb back on board. If you are a confident
swimmer and a reasonable distance from shore, and suspect that rescue may not be
likely, you may attempt to swim. But remember, you will not be able to swim as far
in cold water.
Floating in the H.E.L.P. (Heat Escape Lessening Position) will significantly increase
survival time. Be sure you know how and practice this position. You want to keep
as much body heat as possible from escaping. If you are alone, cross your arms tightly
against the chest and bring your knees up close to the chest.
If there are 3 or more people, huddling in a group is the best option. When you are rescued, be sure
to replace wet clothing with dry and remain in a warm setting until you are confident
that your core body temperature is back to normal.
The Stages of Cold Water Immersion
INITIAL IMMERSION: COLD WATER "SHOCK"
If a person falls into cold water - their body's initial reaction is a 'gasp reflex'
which can include hyperventilation and muscle spasms. This initial reaction can
result in water inhalation as well as significant changes in heart rate and blood
pressure. These initial effects are present for the first two or three minutes of
SHORT-TERM IMMERSION - IMPAIRED FUNCTION
In cold water, you may begin to experience the loss of basic motor skills after
only a few minutes. Between 3 and 30 minutes after immersion a person's hands quickly
lose strength and sensation and subsequently their ability to swim (even strong
swimmers). In cold water immersion cases, boaters often drown as a result of swimming
failure before hypothermia ever has the chance to set in.
LONGER TERM IMMERSION - IMMERSION HYPOTHERMIA
Following 30 or more minutes of immersion, hypothermia - (a drop in body temperature
below the normal level) will begin to set in. The persons overall body temperature
will continue to drop until it reaches the same temperature of the water. Hypothermia
symptoms range from mild to severe. As the body's core temperature falls, a person
will eventually lapse into unconsciousness.
POST RESCUE COLLAPSE:
A drop in blood pressure which may lead person to become unconscious or to stop
breathing at the point of rescue or up to several hours afterward
Cold Water Immersion Animated!