Environmental health

Facilitator: Time: 35 mins; 1345-1420
Actual time:
Learning Objectives:
Materials:

Trench foot and dehydration are concrete manifestations of structural injustice.

Treat trench foot by keeping the feet and socks clean, dry, and elevated.

Losing Heat

Throw out your ideas of hot and cold. We are only going to talk about heat: too much or not enough.

Heat always moves from a place where there's a lot of it to a place where there's less of it. Heat spreads itself out.

If you pick up a glass filled with ice water, what do you feel? "Cold." Think instead that the glass has less heat than your hand, and that over time the hear from your hand will travel to the glass, warming the glass and its contents and making your hand less warm.

Our bodies continuously make heat by burning energy to make the different body functions work. We have a big surface area from which to lose that heat: our skin. We are constantly exchanging heat with our environment, usually losing heat unless the temperature is higher than our body temperature, around 98 degrees Fahrenheit.

What helps us lose that heat?

  • Air -- the warmed air near our skin is carried away by wind and the body continues to lose heat as that warm air is replaced by (usually) cooler air. This is called convection. This doesn't work when the temperature is over 98 degrees; it also works against us when we don't want to lose heat. Wearing layers, trapping the heat near the skin, helps; wearing a wind-proof layer helps.

  • Water -- heat moves quickly into water, so your body gets rid of heat through sweat, which by evaporating lowers the temperature of your skin. If you are wet and your body doesn't have enough heat, you will lose heat faster. The body heat loses heat 20 times faster when it is wet, or when you are in wet clothes. If you need to lose heat, mist with water, put a wet cloth on your head or neck.

  • Earth -- heat moves quickly from a warm body to a less warm ground. This is called conduction. Put something between yourself and the ground to reduce heat loss.

  • Fire -- your brain, and therefore your head, which is alight with righteous indignation, loses a lot of heat by radiation: wear a hat!

How does the body generate and preserve heat?

  • The body can stand surprising extremes of temperature. It changes circulation based on the need to keep or lose heat: when it wants to lose heat, lots more blood flows at the surface of the skin; when it wants to preserve heat, most of the blood is kept away from the skin, especially the hands and feet.

  • Activity levels also has an enormous impact on heat. When sitting quietly, you generate very little heat; running or otherwise exerting yourself, you generate 15 times the heat you did when sitting.

  • Hydration also has a huge impact: someone who is dehydrated has less ability to respond to extremes of temperature. dehydration is just as likely in less warm as in hot weather.

Why do we talk about this so much?

  • Having too much or not enough heat can be a life threatening emergency by itself

  • It also often complicates other injuries and illnesses, so we need to think about heat balance in every person we are treating

Not enough heat: "Cold" and Hypothermia

Feeling "cold" and "not warm" are the same thing.

If someone is not warm, they are losing heat. This will continue until:

  1. They change something about their current situation, including getting out of the cold, or

  2. They get sick from losing too much heat.

What You Can Do

Prevent The Problem

Know the weather. Assume that it will be colder than expected and bring extra clothes, including wind- and water-proof clothing and good warm covering for hands and feet. Fleece is great as long as it isn't an outer layer, since it soaks up nasty chemicals like tear gas.

Hypothermia is most common at 40-60 degrees because folks don't take the temperature as seriously.

Think about how long folks will be in the cold: 40 degrees gets a lot colder after someone has been standing around for a while.

The body needs fuel and water to keep warm:

  • Calories are necessary to generate heat, so eat high calorie foods like nuts, chocolate, fruit, etc.

  • Make sure folks drink enough and that they know where the bathrooms are so they feel like they can keep drinking. Well hydrated folks pee every 2 hours or so, clear and copious.

  • Alcohol, cigarettes, and other drugs can increase heat loss or make folks oblivious to the initial signs of serious problems, so best to avoid them if possible.

  • Keep moving! this will generate heat in your body.

  • Bring stuff to keep folks warm: hand warmers, candied ginger, cayenne for shoes (NOT next to bare skin -- can cause burns).

  • Make sure folks don't get wet, especially during eye flushes.

  • For long actions in cold temperatures, have a warm place to take breaks.

  • Older folks, small children and babies, and folks taking some medications and with some medical conditions are at higher risk, so should be extra careful.

Assessment

  • Shivering is one of the first signs of mild hypothermia: body is working to generate more heat.

  • Cold and not shivering = bad. the body no longer has enough energy to try to warm itself.

  • The "umbles," from less to more severe: fumble, grumble, mumble, stumble, tumble

  • Reclusiveness, apathy: Hypothermia affects the brain, so folks may not be aware that they are in danger.

  • Take hypothermia seriously!!!

Red Flags

  • Anyone who has hypothermia and an altered mental status needs to get more help

  • Someone who doesn't improve despite your efforts to rewarm

Treatment

In case of altered mental status:

  • GET HELP.

  • Don't move them around too much, since the heart could be particularly vulnerable to abnormal (and fatal) rhythms.

  • Lay the person down on a blanket, banner or anything else that will protect them from cold ground.

  • Cover with an emergency blanket.

  • Wait for help. DO NOT try to rewarm.

Everyone else: Get them warm!

  • Get to a warm place.

  • Get them out of any wet clothes; inner layer next to skin, is most important *Have folks jump around, jump around, jump around, do a jig, play tag. If this doesn't help, or person won't jump around, GET HELP.

  • Give warm liquids and easy to digest calories.

  • Put hand warmers where big blood vessels pass near the skin: neck, armpits, groin, inside of elbows

Aftercare

  • Give info sheet on cold-related injuries.

  • Rest, get lots of fluids, stay warm.

  • Anyone who has had anything but the most minor hypothermia is at higher risk for recurrence, so encourage folks to take a break.

Frostbite

Tissues of the skin and sometimes deeper tissues are frozen.

  • Prevent it!

  • Most common in fingers, toes, nose, ears.

  • Skin is cool or cold to touch; can be pale, red, gray, black, waxy and hard.

  • Anyone with possible frostbite needs to get more care: DO NOT rewarm frostbite if there is any chance of refreezing.

  • IF you are going to rewarm,it may be very painful. Gradually raise skin temperature by soaking in lukewarm water (104 - 108 degrees Fahrenheit).

  • Do not massage area -- let it rewarm on its own

Dehydration

Common problem for both hypothermia and hyperthermia.

The human body needs water to work correctly and can lose up to 3 quarts of water an hour with major exertion. Dehydration occurs when you lose more water than you are replacing.

Prevention

  • Start drinking extra fluids several days before the event and continue throughout.

  • Pee should be clear and copious, every 2 hours or so

  • To balance the chemicals in your blood that you lose from sweating and don't replace with plain water: eat nutritious foods; consider Emergen-C (plain gatorade is okay, but many other sports drinks, juices and sodas have too much sugar, which makes it harder for the body to absorb water).

  • If a person is thirsty, they are already dehydrated.

Symptoms

Thirst, dry lips and mouth, dark urine, headache, dizziness, fainting.

Red flags

  • Rapid pulse that does not slow down within a few minutes when the person is calm.

  • Any altered mental status.

Treatment

Drink! if the person can hold a cup, they are alert enough to drink.

Too much heat: Hyperthermia

Hyperthermia is the opposite of hypothermia, but the principles are the same.

Sometimes the body wants to LOSE heat, and if the environment doesn't let that happen people get hyperthermia, or too much heat.

The worst form of heat-related illness is heat stroke. 50% of people who get heat stroke die, so it is important to prevent it.

Prevention

  • If traveling to a new place, you are at higher risk of problems. It can take up 2 weeks for a body to adjust to new temperature and new elevation.

  • Know the weather and prepare for it. Humidity actually makes it harder to lose heat because sweat does not evaporate. Misting with water will help in lower humidity. Wind also helps get rid of heat.

  • Protect from the sun: Cover your head and wear loose clothing that covers skin (especially for people who get sunburn); wear oil-free sunscreen.

  • Bring water, water, water and be sure you drink it! Know where the bathrooms are, because folks should be using them every 2 hours or so.

  • Don't over exert yourself. Rest often in cool, shady places.

Symptoms

  • Same as dehydration: Thirst, dry lips and mouth, dark urine, headache, dizziness, fainting.

    • Fainting is often caused by a combination of dehydration, heat, and blood pooling in legs so it can't get to the brain

    • Commonly occurs in big crowds that aren't moving

    • Prevent by moving around a bit within the crowd

  • Also: fatigue; nausea; muscle cramps ("heat cramps"); feeling hot; feeling thirst; cool, clammy skin or slightly flushed skin.

Red Flags

  • Any altered mental status, including seizures.

  • Vomiting.

  • Skin red and hot.

Treatment

Cool down, get fluids:

  • Get to cool, shady place

  • Give liquids.

  • Mist with water and fan.

  • It takes a while to recover. Stay with this person for at least an hour, and then encourage them to take it easy for the rest of the day if not longer.

Aftercare

  • Give info sheet on heat related injuries.

  • Continue treatment: rest, get lots of fluids, stay cool.