VIEWS: 42 PAGES: 51 POSTED ON: 1/7/2010
It has been cold outside at Work in Alberta Have you asked or talk to the guys and gals about Frost bite Superficial Frostbite • includes all layers of the skin • initially redness in light skin, grayish in dark skin • burning, tingling, itching, or cold sensations in the affected areas, followed by numbness • skin turns white, waxy; some resistance when pressed (feels firm or “wooden” but underlying tissue is soft); cold to the touch • may have blistering Deep Frostbite • involves skin, muscle, tendons, nerves, blood vessels; may include bone • white or yellowish waxy skin that turns purplish blue as it thaws • underlying tissue hard, no resistance when pressed, may appear blackened and dead • blood-filled blisters and swelling may develop • may develop blood clots Deep Frostbite • significant pain as affected areas re-warm; dull continuous ache becomes throbbing sensation in 2-3 days and may last weeks to months • frostbitten skin is highly susceptible to infection, and gangrene (death and decay of body tissues) may develop • time will reveal the final amount of tissue damage • many people with frostbite may also be experiencing hypothermia Cold-related Injuries and Illnesses Hypothermia, Frostbite, and Other Health Problems What this presentation covers • Summary of factors increasing risk of cold-related injuries and illnesses • Summary of preventive measures against cold-related injuries and illnesses • Causes, signs and symptoms, and treatment of – Hypothermia – Frostbite – Frostnip – Chilblains – Immersion Foot (Trench foot) Factors Increasing Risk of Cold Injuries/Illnesses • Previous cold-related injury • Predisposing health conditions • Fatigue, poor physical condition • Poor nutrition • Nicotine (Smoking) • Age • Improper clothing and equipment • Under-activity • Dehydration • Medication • Alcohol • Caffeine • Over-activity • Cold conditions: –Temperature –Wind –Wetness • Length of exposure Preventing Cold-related Injuries and Illnesses • Wear appropriate clothing. • Avoid wetness or excessive sweating. • Stay dry. Change into dry clothes and shoes if they become wet. • Keep active. Avoid sitting or standing still for prolonged periods. • Take frequent breaks in warm, shielded areas. • Work in pairs to keep an eye on each other. • Consume warm, high calorie food often. • Drink plenty of warm non-caffeinated, non-alcoholic liquids. • Don’t smoke. Hypothermia Hypothermia ("low heat”) is a potentially serious and fatal health condition resulting from the body’s failure to maintain its normal core temperature of 98.6°F. Hypothermia is a medical emergency! Hypothermia Body temperature that is too low affects the brain, making the affected person unable to think clearly or move well. This makes hypothermia particularly dangerous because a person may not realize it is happening and may deny being in any trouble. Recognition of symptoms depends on co-workers' ability to identify symptoms and to seek medical help. Hypothermia Most cases of hypothermia occur in air temperatures from 30°F to 40°F. However, it can occur at warmer temperatures as high as 65°F, or more, if a person becomes chilled from prolonged exposures to wetness (rain, snow, submersion in cold water, or sweat) and accompanying winds. Generally, in cold dry environ- ments, hypothermia occurs over a period of hours. In cold water, core temperature can drop to dangerous levels in a matter of minutes. Immersion Hypothermia Water transfers heat away from the human body 25 times faster than air, so even moderate water temperatures can be dangerous in a relatively short time. Water Temperature in Degrees F (Degrees C) 32.5 (0.3) Exhaustion or Unconsciousness Under 15 min. Expected Time of Survival Under 15 to 45 min. 32.5 to 40 (0.3 to 4.5) 40 to 50 (4.5 to 10) 50 to 60 (10 to 15.5) 60 to 70 (15.5 to 21) 70 to 80 (2 to 26.5) Over 80 (Over 26.5) 15 to 30 min. 30 to 60 min. to 2 hrs. 2 to 7 hrs. 2 to 12 hrs. Indefinite 30 to 90 min. to 3 hrs. to 6 hrs. 2 to 40 hrs. 3 hrs. to indefinite Indefinite Stages of Hypothermia Hypothermia progresses through three indistinct but sequential stages as core body temperature continues to decline: Approximate Core Body Temperature Mild hypothermia Moderate hypothermia 98°F - 95°F 95°F - 90°F <90°F Severe hypothermia Mild Hypothermia Signs/Symptoms Physical Mental • shivering, mild to severe • sensation of cold, then pain in extremities • pale, waxy, cold skin • numbness of hands • unable to perform complex tasks (fumbling with items in the hand) • irritability • able to walk and talk If shivering can be stopped voluntarily mild hypothermia Moderate Hypothermia Signs/Symptoms Physical Mental • intense shivering becomes persistent and violent • sluggish; labored movements • stumbling • confused, may appear alert • irrational behavior – “Paradoxical Undressing” (person starts to undress, unaware s/he is cold) • loss of fine motor coordination in hands (fumbling) Watch for the “-umbles” • stumbles • mumbles • fumbles • grumbles • apathetic/flattened affect – "I don't care” attitude" • withdrawn behavior • slurred speech, difficulty speaking • sluggish thinking • signs of depression Severe Hypothermia Signs/Symptoms Physical Mental • shivering stops • exposed skin blue or puffy • muscle coordination very poor, muscle rigidity • stupor • can’t walk; falls to ground and curls up into fetal position to conserve heat • incoherent, irrational behavior • may be able to maintain posture and appearance of awareness • semi-conscious, drowsy • loss of awareness of others • amnesia, memory lapses • decreased pulse and respiration rate • irregular heart rhythm Possible Death from Hypothermia “No one is dead until warm and dead” Core body temperature below 82°F - 78°F Physical Mental • erratic, shallow breathing • may not be able to feel pulse • pupils dilated and fixed • cold, blue skin • unresponsive to any stimuli • Brain activity seriously slowed • unconscious, appears comatose or dead Worker may appear dead and show all the accepted clinical signs of death, but many of these people have made complete recoveries when rewarmed. • pulmonary edema, cardiac and respiratory failure • death possible below 78°F Treatment of Hypothermia Treatment depends on the severity of the hypothermia. Mild Hypothermia • Remove wet clothes from victim and replace with dry clothes and/or wrap in warm blankets; cover the head. • Move to a warm environment. • Do not exercise to warm up. • Do not re-warm person in a warm bath or by massaging or rubbing. • Drink a warm (not hot) sugary drink Avoid drinks with caffeine (coffee, tea, or hot chocolate) or alcohol. Handle the victim gently and minimize his or her exertion. • Transport victim to an emergency medical facility for evaluation. Treatment of Hypothermia Moderate Hypothermia • Call for emergency help. • Follow the procedures on the preceding slide. In addition: • Cover all extremities completely, place very warm objects, such as hot packs or water bottles on the victim's head, neck, chest and groin. Arms and legs should be warmed last. Handle the victim gently. Rough handling can cause heartbeat irregularities and death. Treatment of Hypothermia Severe Hypothermia • Call for emergency help. • Give CPR if necessary. • Follow the procedures for treating mild hypothermia. • Do not apply external heat (hot water bath, heat lamp, electric blanket, electric heater, etc.) to re-warm. Handle the victim very gently. Transport to hospital for treatment as soon as possible. • Transport the victim to an emergency medical facility as soon as possible. Frostbite In cold conditions, your body reduces heat loss and increases heat production in order to maintain an internal (core) body temperature of 98.6°F. Normal core body temperature: Body Core Heart Brain Lungs • Liver • Kidneys 98.6°F Over time, your body will decrease blood flow to your extremities and outer skin and shift it to the body core to keep the internal organs warm. However, this allows exposed skin and the extremities to cool rapidly and increases the risk of cold-related injuries, such as frostbite. Extremities • Legs, feet • Arms, hands Frostbite Frostbite occurs when the deep layers of the skin and other body tissues freeze (tissue temperature <28°F-30°F). Ice crystals form, destroying tissues and causing permanent damage. In severe cases, amputation of the frostbitten area may be required. Frostbite typically affects the • toes/feet • fingers/ hand • ears • nose • cheeks • chin These parts are farthest from the body core, receive less blood flow, and are thinner so they cool faster. Frostbite Causes • Exposure to below freezing temperatures • Can occur in above freezing temperatures due to wind chill factors and wetness • Contact with extremely cold objects (especially metal) • Contact with cooled or compressed gases, at normal temperatures (e.g., liquid nitrogen) air temp. + wind + wetness cold condition = Direct skin exposure to freezing metal, extreme cold, or high winds can cause frostbite in minutes. Chilblains Chilblains is caused by prolonged and repeated exposure of bare skin to air temperatures above freezing (32°F) to 60°F, accompanied by high humidity or wet conditions. It can develop in only a few hours. • The most commonly affected areas are the cheeks, ears, nose, fingers, and toes. • Affected area appears as red, swollen skin which is tender, hot to the touch, and may itch • Can worsen to aching, prickly (pins and needles) sensation, then numbness. • In severe cases, open sores or bleeding lesions may result from continued exposure. Chilblains Treatment • Warm affected area gently with direct body heat: – put bare hands over the affected area on the face – put affected areas against armpits or stomach of another person • Do not massage or rub affected areas. • Do not wet the area or rub it with snow or ice. • Do not expose affected area to open fire, stove, or any other intense heat source. • Seek medical attention to evaluate for tissue damage. Signs and symptoms of tissue damage may be slow to appear. Immersion Injury (Trench foot) Immersion injury (trench foot) results from prolonged exposure of the feet to wet or damp cool conditions, such as in cold water, mud, or wet fields, or wearing damp socks. A similar condition of the hands can occur if a person wears wet gloves for a prolonged period under cold conditions. • Usually develops slowly, over hours to days and at temperatures from 32°F to 50°F. • Can occur at temperatures as high as 60 degrees F if the feet are constantly wet • The primary injury is to nerve and muscle tissue. There is no formation of ice crystals in the tissues but immersion injury can cause permanent damage. Photo courtesy of USACHPPM Immersion Injury (Trench foot) Symptoms • Initially reddened skin, then turns pale and mottled, finally purple, grey, or blue • Tingling pain, itching, burning sensation, or numbness may occur, followed by leg cramps and swelling • May cause permanent damage to the circulatory system so person is more sensitive and prone to cold-related injuries in that area Note the cyanosis (blueness of skin) around the nail beds; redness and swelling; and blisters. • May develop blisters, ulcers, and gangrene. Amputation may be necessary Photo courtesy of USACHPPM Immersion Injury (Trench foot) Treatment • Remove wet clothing and replace with dry, warm clothing. • Warm affected area slowly at room temperature. Carefully clean, dry, and wrap loosely with sterile dressing, taking care not to break the blisters. This can lead to infection. • Elevate feet to reduce swelling. • Do not walk on injured feet. • Seek prompt medical attention; trench foot can cause severe disability. Immersion Injury (Trench foot) Prevention • Keep feet clean and dry. • Check them regularly; if they get wet from water or sweat, dry them and replace with dry socks. • Change socks at least every 8 hours or whenever wet and apply foot powder. Foot powder with aluminum hydroxide can help. • Don’t wear tight socks; this can further impair circulation. • Don’t sleep with wet socks. Maintaining Temperature: Balancing Heat Loss and Heat Production Over time, your body will decrease blood flow to your extremities and outer skin and shift it to the body core to keep the internal organs warm. However, this allows exposed skin and the extremities to cool rapidly and increases the risk of coldrelated injuries, such as frostbite and hypothermia. Challenges from Cold Conditions Cold conditions force your body to work harder to maintain its temperature. The challenges you face from a cold environment include: • Air temperature • Wetness: rain, snow, ice, humidity; sweat; wet clothes; water • Air movement: wind speed (5 miles per hour and higher); blown air from fan in cold rooms, etc. Wind Chill Chart Example: If the temperature is -15°F and wind speed is 10 mph, it will feel like it’s -35°F, and frostbite will develop in 30 minutes. If the wind speed doubles to 20 mph, the time for frostbite to occur drops to only 10 minutes. How the Body Loses Heat EVAPORATION: heat loss in the form of vapor when body uses heat to evaporate moisture from skin surface (perspiration or “sweat”) RESPIRATION: heat loss from lungs’ warming inhaled cold air, which is then exhaled RADIATION: heat CONVECTION: heat loss from wind* removing the layer of warm air next to the skin; rate of heat loss depends on wind/air speed *or blown air from fan, etc. loss from exposed body areas to the environment due to the difference between the temperature of the body and that of the cooler air (when air is <98.6°F) ` CONDUCTION: heat loss through contact with a cooler object and transfer of heat to the cooler object; increases when in contact with cold wet objects (generally, conduction accounts for 2-3% of total heat loss in dry conditions; with wet clothes the loss is increased 5x, and rate of heat loss is 25x faster when a person is immersed in cold water) How the Body Loses Heat Each of these means of heat loss can play a large or small role in the development of a cold-related injury. In addition to air temperature, air movement (wind speed), and wetness, the skin surface area that is exposed to the cold is a factor in the amount of heat lost from the body. Factors in heat loss: • Air temperature, wind speed, wetness • Area of skin surface exposed to cold (particularly in radiation) • Contact with cold water or surfaces How the Body Produces Heat Your body must produce an equal amount of heat to counter-balance the heat loss in order to survive and stay active in the cold. Heat is produced in the following ways: • Metabolism: biochemical reactions in the body which produce heat as a by-product • Physical Activity (exercise/work): muscles produce most of the heat during physical work • Shivering: inefficient quivering of the muscles that increases the body’s heat production; limited to a few hours because of depletion of muscle “fuel” stores and the onset of fatigue How the Body Produces Heat Factors important in heat production: Factors influencing heat retention and tolerance to cold: • Food intake • "Fuel" (glycogen) store • Fluid balance • Size and shape of the body (surface to volume ratio) • Layer of fat under the skin • Decreased blood flow through the skin and extremities • Insulation (clothing) Cold Stress If your body begins to lose heat faster than it is produced, your core body temperature drops below normal, and cold stress may result. Cold stress doesn’t only happen when conditions are below freezing; it can also be brought about by temperatures in the 50's coupled with some rain and wind. How does cold affect work performance? Uncomfortably cold working conditions (combination of temperature, wetness, wind) Immediate signs: • decreased alertness • restlessness, lack of concentration • impaired performance of complex mental tasks • impaired ability to perform manual tasks • numbness, muscle weakness, stiffened joints Lower work efficiency Higher accident rates Factors Increasing Risk of Cold Injuries/Illnesses In general, people in good physical health are less susceptible to cold injury. In addition to weather conditions, the following factors may increase the risk of developing a cold injury: • Previous cold-related injury • Predisposing health conditions: Cardiovascular disease, Diabetes, Anemia, Sickle cell disease, Vibration/White finger disease, other conditions associated with poor circulation, Hypertension, Asthma • Fatigue, poor physical condition • Poor nutrition • Medication: Anti-depressants, Sedatives, Tranquilizers, Others • Alcohol: Decreases awareness; impairs the body’s ability to regulate temperature and increases risk for hypothermia • Caffeine: Increases urine production, contributes to dehydration Factors Increasing Risk of Cold Injuries/Illnesses • Nicotine (Smoking): increases risk for cold-induced skin injury (such as frostbite, immersion foot); promotes development of peripheral vascular disease • Wearing tight clothing: restricts circulation • Under-activity: can lead to decreased body heat production • Over-activity: can lead to wet skin, clothing, or shoes from sweating • Under-dressing: exposed fingers, nose, ears; uncovered head • Over-dressing: can result in wet skin and clothing from sweating • Length of exposure • Age: older adults may be at more risk than younger • Dehydration: Causes body’s natural defense mechanisms to fail and person becomes more susceptible to cold injuries Engineering Controls • Use radiant heaters, warm air jets, and contact warm plates to warm workers. • Shield work areas from drafts or wind to reduce wind chill. • Provide heated warming shelters, e.g., tents, cabins, or rest rooms, for continuous work in temperatures below freezing. • Cover equipment handles, especially metal handles and bars, with thermal insulating material when temperatures drop below freezing (steel conducts heat away even faster than water). • Design machines and tools so that they can be operated without having to remove gloves or mittens. • In refrigerated rooms, minimize air speed as much as possible with properly designed air distribution systems. If workers are simultaneously exposed to vibration and/or toxic substances, reduced limits for cold exposure may be necessary. Clothing The following are recommendations to protect your body, hands, feet, and head when working in cold environments: • Body: Wear at least three layers of loose-fitting clothing to trap air and provide insulation, and allow better ventilation. 1. Inner wicking layer made from polyester, polypropylene, or other synthetic material that draws moisture away from the skin and helps keep it dry. 2. Middle insulating layer made of wool, down, fleece, or other material with loft that will hold the body’s heat. Clothing • Body: Wear at least three layers of loose-fitting clothing to trap air and provide insulation, and allow better ventilation. 3. Outer layer for wind and water protection, made of “breathable” waterproof fabric that allows some ventilation (like Gortex® or nylon) and is windproof, and that may also need to be resistant to oil, fire, chemicals, or abrasion. Any additional layer(s) of clothing should be large enough not to compress the inner layers and decrease the insulation properties. Clothing • Head: Wear a wool knit cap or a liner under a hard hat to reduce excessive heat loss. A mask also helps protect the cheeks and nose. Up to 40% of body heat can be lost when the head is left exposed. Clothing • Hands: Wear gloves and mittens to prevent cold-related injuries as well as prevent accidents and maintain dexterity. The ACGIH* recommends wearing gloves when the air temperature is: – – – – below 60.8°F for sedentary work below 39.2°F for light work below 19.4°F for moderate work below 0°F, wear mittens, which protect better than gloves Use glove/mitten liners for extra protection. Use fingerless gloves with mittens for work requiring dexterity. Clothing • Feet: Wear insulated boots with removable felt liners; remove liners daily for complete drying. Leather “mukluk” or “pack” type boots are porous, allowing the boots to "breathe" and letting perspiration evaporate. – If work involves standing in water or slush (e.g., fire fighting, farming), boots must be waterproof. – If there are crushing hazards, boots thick socks.steel-toed. – Wear warm must be If you wear two pairs of socks, inner liner socks made of polypropylene will help keep feet dry and warmer (silk, nylon, or thin wool will work also). Outer thicker socks should be larger so inner socks are not compressed. Clothing (Socks, continued) • Make sure socks are not too thick; this may result in tightness and loss of insulating properties, and increase the risk for cold injuries. If the socks are too thin, the boots will fit loosely and may lead to blisters. • Change socks if they get wet or damp General • Keep clothing dry. Remove snow and moisture from clothes prior to entering heated shelters. While resting in a heated area, remove outerwear to allow perspiration to evaporate. • Keep extra complete change of dry clothing, shoes, hat, gloves, etc., available in case work clothes become wet. The body loses heat faster if skin is in contact with wet clothing, and will chill rapidly. Excess perspiration will increase heat loss, so remove extra layers of clothing whenever you feel too warm. Personal Protective Equipment Face and Eye Protection • In extremely cold conditions where face protection is needed, use eye protection that is separate from the nose and mouth to prevent fogging and frosting eye shields or glasses • Wear eye protection appropriate for the work • Wear eye protection that protects against – ultraviolet light from the sun – glare from the snow – blowing snow/ice crystals – high wind chill conditions to protect the corneas of the eyes from potentially freezing Work Practices Work Practices are important preventive measures. • Pace the work to avoid excessive sweating. Change into dry clothes if clothes become wet. New employees should be given enough time to get acclimatized to cold and protective clothing before assuming a full work load. • Avoid sitting or standing still for prolonged periods. • Take frequent breaks, in shielded areas out of the cold, to avoid fatigue since energy is needed to keep muscles warm. • Work in pairs to keep an eye on each other and watch for signs of cold stress. • Consume warm, high calorie food such as pasta to maintain energy reserves. Working in the cold requires more energy to maintain body heat. Work Practices • Drink plenty of warm liquids often, especially when doing strenuous work, to prevent dehydration. Avoid caffeine, which increases urine production and contributes to dehydration. Avoid alcohol. • When it is cold, do not brush up against metal surfaces with bare skin. The skin may stick to it and get immediate frostbite. • Greases and oils get thick and hard which makes equipment difficult to use. Follow the proper procedures and use the right tools. Tools also get brittle in the cold, so use caution when working with them. • Avoid skin contact when handling evaporative liquids (gasoline, alcohol, cleaning fluids) while de-icing and fueling below 40°F. These materials in contact with the skin greatly increase heat loss from the body. Thank you for taking the time to learn about safety and health and how to prevent future injuries and illnesses.
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