As the weather is becoming colder in many parts of the northern hemisphere, the time is coming that we’ll all be working hard to stay warm.
Many textbooks spend a brief time discussing hypothermia, but put much more emphasis on Frostbite. So here’s a question for the group. . . If the temperature is 34*F (1* C) and the wind is 30 mph (48 Kph) can you get frostbite? The answer is no, for frostbite to occur the water in the cells must freeze. Water will not freeze above 0*C.
Even at temperatures far above freezing the body’s core temperature can cool to dangerous levels. The body has some great mechanisms to maintain temperature. First the body will shunt blood away from the periphery to maintain heat at the central core. (consider your appendicular areas like a big heat-sync. )
As this mechanism fails to maintain temperature the body begins more active ways to rewarm. Shivering causes a rapid contraction and relaxation of the muscles to create heat through movement.
At about 93*F (34*C) the shivering ends, the body can no longer expend the energy and goes into a shutdown mode to preserve the body. The pulse will slow, the level of consciousness will reduce, the motor control will be affected. If we do not actively rewarm the body these shutdown mechanisms will continue until we can no longer “restart” the body.
All of our intuition tells us to remove the patient from the environment and cover them up. Removal is important, but to cover them may not help. As I stated earlier, the body pulls blood away from the exterior leaving a cold body. Since blankets don’t actively provide heat they will only insulate the cold inside. We need to actively rewarm with warm packs, warm (non-caffeinated) water or drinks. We need to warm them from the core, not a warm room.
Since the body has closed down the limbs to blood flow, any remaining blood in the appendicular areas will also cool. If we rewarm from the periphery (i.e. a warm room) the cold blood will return to the core and cause and after drop.
Years ago the Boy Scouts would recommend that rewarming someone was easiest by taking the patient and another person and having them cuddle together inside of a single sleeping bag. This method works but should probably be reserved to a last resort as we maintain professionalism.
Hopefully everyone in the North is looking forward to the cold, it’s going to be a long time before we can be warmed by the sun again. For all the readers in South, try to stay cool 🙂