Sunday, January 3, 2010

Avoirdupois, and the hunter's response

I like the way this article is written. Also, from it, I learned a new word.

Avoirdupois. The word avoirdupois is from Old French aveir de peis (later avoir de pois), literally "goods of weight" (Old French aveir, "property, goods", also "to have", comes from the Latin habere, "to have, to hold, to possess property"; de = "from", cf. Latin; peis = "weight", from Latin pensum).

The article above, on freezing to death.

"But for all scientists and statisticians now know of freezing and its physiology, no one can yet predict exactly how quickly and in whom hypothermia will strike--and whether it will kill when it does. The cold remains a mystery, more prone to fell men than women, more lethal to the thin and well muscled than to those with avoirdupois, and least forgiving to the arrogant and the unaware.

The process begins even before you leave the car, when you remove your gloves to squeeze a loose bail back into one of your ski bindings. The freezing metal bites your flesh. Your skin temperature drops.

Within a few seconds, the palms of your hands are a chilly, painful 60 degrees. Instinctively, the web of surface capillaries on your hands constrict, sending blood coursing away from your skin and deeper into your torso. Your body is allowing your fingers to chill in order to keep its vital organs warm."

Oh, and hunter's response.

Were you a Norwegian fisherman or Inuit hunter, both of whom frequently work gloveless in the cold, your chilled hands would open their surface capillaries periodically to allow surges of warm blood to pass into them and maintain their flexibility. This phenomenon, known as the hunter's response, can elevate a 35-degree skin temperature to 50 degrees within seven or eight minutes.

Other human adaptations to the cold are more mysterious. Tibetan Buddhist monks can raise the skin temperature of their hands and feet by 15 degrees through meditation. Australian aborigines, who once slept on the ground, unclothed, on near-freezing nights, would slip into a light hypothermic state, suppressing shivering until the rising sun rewarmed them...

... The exertion that warmed you on the way uphill now works against you: Your exercise-dilated capillaries carry the excess heat of your core to your skin, and your wet clothing dispels it rapidly into the night....

...With every one-degree drop in body temperature below 95, your cerebral metabolic rate falls off by 3 to 5 percent. When your core temperature reaches 93, amnesia nibbles at your consciousness.

Your head drops back. The snow crunches softly in your ear. In the minus-35-degree air, your core temperature falls about one degree every 30 to 40 minutes, your body heat leaching out into the soft, enveloping snow. Apathy at 91 degrees. Stupor at 90.

You've now crossed the boundary into profound hypothermia. By the time your core temperature has fallen to 88 degrees, your body has abandoned the urge to warm itself by shivering. Your blood is thickening like crankcase oil in a cold engine. Your oxygen consumption, a measure of your metabolic rate, has fallen by more than a quarter. Your kidneys, however, work overtime to process the fluid overload that occurred when the blood vessels in your extremities constricted and squeezed fluids toward your center. You feel a powerful urge to urinate, the only thing you feel at all...

... At 85 degrees, those freezing to death, in a strange, anguished paroxysm, often rip off their clothes. This phenomenon, known as paradoxical undressing, is common enough that urban hypothermia victims are sometimes initially diagnosed as victims of sexual assault. Though researchers are uncertain of the cause, the most logical explanation is that shortly before loss of consciousness, the constricted blood vessels near the body's surface suddenly dilate and produce a sensation of extreme heat against the skin"...

There is hope.

..."The doctor shakes his head. He can't remember seeing numbers so low. He's not quite sure how to revive this man without killing him.

In fact, many hypothermia victims die each year in the process of being rescued. In "rewarming shock," the constricted capillaries reopen almost all at once, causing a sudden drop in blood pressure. The slightest movement can send a victim's heart muscle into wild spasms of ventricular fibrillation. In 1980, 16 shipwrecked Danish fishermen were hauled to safety after an hour and a half in the frigid North Sea. They then walked across the deck of the rescue ship, stepped below for a hot drink, and dropped dead, all 16 of them."..

Ideally, the doctor would have access to a cardiopulmonary bypass machine, with which he could pump out the victim's blood, rewarm and oxygenate it, and pump it back in again, safely raising the core temperature as much as one degree every three minutes. But such machines are rarely available outside major urban hospitals. Here, without such equipment, the doctor must rely on other options.

"Let's scrub for surgery," he calls out...

For the next half hour, an EMT quietly calls the readouts of the thermometer, a mantra that marks the progress of this cold-blooded proto-organism toward a state of warmer, higher consciousness.


So. awesomely. fucked. up.

This is great.

And on that note, I'm off to enjoy Sunday outside.

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