Presentation on theme: "Cold-related Injuries"— Presentation transcript:
1Cold-related Injuries Hypothermia, Frostbite, Chilblains and Trench FootJanuary, 2011
2What This Presentation Covers Summary of factors increasing risk of cold- related injuries and illnessesSummary of preventive measures against cold- related injuries and illnessesCauses, signs and symptoms, and treatment of:HypothermiaFrostbiteFrostnipChilblainsImmersion Foot (trench foot)See “Working in Cold Environments” for more information on the causes and risk factors of cold-related illnesses and injuries, and preventive measures to minimize the hazards from cold exposure.
3Factors Increasing Risk of Cold Injuries/Illnesses Nicotine (Smoking)AgeImproper clothing and equipmentUnder-activityOver-activityCold conditions:TemperatureWindWetnessLength of exposurePrevious cold-related injuryPredisposing health conditionsFatigue, poor physical conditionPoor nutritionDehydrationMedicationAlcoholCaffeine
4Preventing 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.
5Hypothermia is a medical emergency! 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.When exposed to cold conditions, your body begins to lose heat faster than it can be produced. Prolonged exposure to cold eventually uses up your body’s stored energy and your core body temperature drops to 95°F or below. The result is hypothermia.Hypothermia is a medical emergency!
6Hypothermia (Cont.)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.
7Most cases of hypothermia occur in air temperatures from 30°F to 40°F. Hypothermia (Cont.)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 environments, hypothermia occurs over a period of hours. In cold water, core temperature can drop to dangerous levels in a matter of minutes.Most cases of hypothermia occur in air temperatures from 30°F to 40°F.
8Immersion 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)Exhaustion or UnconsciousnessExpected Time of Survival32.5 (0.3)Under 15 min.Under 15 to 45 min.32.5 to 40 (0.3 to 4.5)15 to 30 min.30 to 90 min.40 to 50 (4.5 to 10)30 to 60 min.to 3 hrs.50 to 60 (10 to 15.5)to 2 hrs.to 6 hrs.60 to 70 (15.5 to 21)2 to 7 hrs.2 to 40 hrs.70 to 80 (2 to 26.5)2 to 12 hrs.3 hrs. to indefiniteOver 80 (Over 26.5)Indefinite
9Approximate Core Body Temperature Stages of HypothermiaHypothermia progresses through three indistinct but sequential stages as core body temperature continues to decline:Approximate Core Body TemperatureMild hypothermia98°F - 95°FModerate hypothermia95°F - 90°FSevere hypothermia<90°F
10If shivering can be stopped voluntarily mild hypothermia Signs/SymptomsPhysicalMentalShivering, mild to severeSensation of cold, then pain in extremitiesPale, waxy, cold skinNumbness of handsUnable to perform complex tasks (fumbling with items in the hand)Able to walk and talkIrritabilityIf shivering can be stopped voluntarily mild hypothermia
11Watch for the “-umbles” Moderate HypothermiaSigns/SymptomsPhysicalMentalIntense shivering becomes persistent and violentSluggish; labored movementsStumblingLoss of fine motor coordination in hands (fumbling)Confused, may appear alertIrrational behavior – “paradoxical undressing” (person starts to undress, unaware s/he is cold)Apathetic/flattened affect – "I don't care” attitude"Withdrawn behaviorSlurred speech, difficulty speakingSluggish thinkingSigns of depressionWatch for the “-umbles”stumblesmumblesfumblesgrumbles
12Severe Hypothermia Signs/Symptoms Physical Mental Shivering stops Exposed skin blue or puffyMuscle coordination very poor, muscle rigidityStuporCan’t walk; falls to ground and curls up into fetal position to conserve heatDecreased pulse and respiration rateIrregular heart rhythmIncoherent, irrational behaviorMay be able to maintain posture and appearance of awarenessSemi-conscious, drowsyLoss of awareness of othersAmnesia, memory lapses
13Possible Death from Hypothermia Core body temperature below 82°F - 78°FPhysicalMentalErratic, shallow breathingMay not be able to feel pulsePupils dilated and fixedCold, blue skinUnresponsive to any stimuliPulmonary edema, cardiac and respiratory failureDeath possible below 78°FBrain activity seriously slowedUnconscious, appears comatose or deadWorker may appear dead and show all the accepted clinical signs of death, but many of these people have made complete recoveries when re-warmed.“No one is dead until warm and dead”
14Treatment of Hypothermia Mild HypothermiaTreatment depends on the severity of the 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.Transport victim to an emergency medical facility for evaluation.Handle the victim gently and minimize his or her exertion.
15Treatment of Hypothermia (con’t.) Moderate HypothermiaCall 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.
16Treatment of Hypothermia (Con’t.) Severe HypothermiaCall 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.Transport the victim to an emergency medical facility as soon as possible.Handle the victim very gently. Transport to hospital for treatment as soon as possible.
17Normal core body temperature: FrostbiteNormal core body temperature:98.6°FIn cold conditions, your body reduces heat loss and increases heat production in order to maintain an internal (core) body temperature of 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.Body CoreHeartBrainLungsLiverKidneysExtremitiesLegs, feetArms, hands
18Frostbite (Con’t.)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/feetfingers/ handearsnosecheekschinThese parts are farthest from the body core, receive less blood flow, and are thinner so they cool faster.
19Frostbite (Con’t.) Causes Exposure to below freezing temperatures air temp. +wind+wetnesscold condition=Exposure to below freezing temperaturesCan occur in above freezing temperatures due to wind chill factors and wetnessContact with extremely cold objects (especially metal)Contact with cooled or compressed gases, at normal temperatures (e.g., liquid nitrogen)Direct skin exposure to freezing metal, extreme cold, or high winds can cause frostbite in minutes.
20Frostbite can be classified into two main divisions: Frostbite (Con’t.)Frostbite can be classified into two main divisions:Superficial (mild)Deep (severe)The extent of frostbite depends on the extremeness of conditions and duration of exposure.
21Superficial Frostbite Includes all layers of the skinInitially redness in light skin, grayish in dark skinBurning, tingling, itching, or cold sensations in the affected areas, followed by numbnessSkin turns white, waxy; some resistance when pressed (feels firm or “wooden” but underlying tissue is soft); cold to the touchMay have blisteringPhotos courtesy of USACHPPM
22Deep FrostbiteInvolves skin, muscle, tendons, nerves, blood vessels; may include boneWhite or yellowish waxy skin that turns purplish blue as it thawsUnderlying tissue hard, no resistance when pressed, may appear blackened and deadBlood-filled blisters and swelling may developMay develop blood clotsPhotos courtesy of USACHPPM
23Deep FrostbiteSignificant pain as affected areas re-warm; dull continuous ache becomes throbbing sensation in 2-3 days and may last weeks to monthsFrostbitten skin is highly susceptible to infection, and gangrene (death and decay of body tissues) may developTime will reveal the final amount of tissue damageMany people with frostbite may also be experiencing hypothermiaPhotos courtesy of USACHPPM
24Treatment of Frostbite Move the person to a warm dry area. Don’t leave the person alone.Remove any wet or tight clothing that may cut off blood flow to the affected area.Treat for hypothermia if victim is also experiencing hypothermia. Saving their lives is more important than preserving a finger or foot. Perform CPR if necessary.Do not rub the affected area, because rubbing causes damage to the skin and tissue.Gently place the affected area in a warm (105°F) water bath and monitor the water temperature to slowly warm the tissue. Don’t pour warm water directly on the affected area because it will warm the tissue too fast causing tissue damage. Warming takes about minutes.
25Treatment of Frostbite After the affected area has been warmed, it may become puffy and blister. The affected area may have a burning feeling or numbness. When normal feeling, movement, and skin color have returned, the affected area should be dried and wrapped to keep it warm.Seek medical attention as soon as possible.NOTE: If there is a chance the affected area may get cold again, do not warm the skin. If the skin is warmed and then becomes cold again, it will cause severe tissue damage.
26FrostnipFrostnip is the mildest form of a freezing cold injury. Only the very outer layers of the skin freeze, usually on the cheeks, earlobes, fingers, and toes, and also nose and chin.Usually occurs at about 29°FGenerally reversible, no tissue injury or permanent damageSkin turns white, top layer of skin feels hard but deeper tissue still feels normal (soft)May feel tingling or numbness
27FrostnipTreatmentGently re-warm affected area by blowing warm air on it or placing it against a warm body part (e.g., another person’s stomach or armpit).Do not use very hot objects such as hot water bottles to re-warm the area or person.Do not rub the affected part - ice crystals in the tissue can cause damage if the skin is rubbed.Frostnip can be prevented by wearing warm clothing, gloves and insulated footwear.
28ChilblainsChilblains 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 itchCan worsen to aching, prickly (pins and needles) sensation, then numbness.In severe cases, open sores or bleeding lesions may result from continued exposure.
29Chilblains (Con’t.) Treatment Warm affected area gently with direct body heat:Put bare hands over the affected area on the facePut affected areas against armpits or stomach of another personDo 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.Treatment
30Immersion 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 wetThe 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
31Immersion Injury (Trench foot) SymptomsInitially reddened skin, then turns pale and mottled, finally purple, grey, or blueTingling pain, itching, burning sensation, or numbness may occur, followed by leg cramps and swellingMay cause permanent damage to the circulatory system so person is more sensitive and prone to cold-related injuries in that areaMay develop blisters, ulcers, and gangrene. Amputation may be necessaryPhoto courtesy of USACHPPMNote the cyanosis (blueness of skin) around the nail beds; redness and swelling; and blisters.
32Immersion Injury (Trench foot) TreatmentRemove 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.
33Immersion Injury (Trench foot) PreventionKeep 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.
34Resources – for further information Canadian Centre for Occupational Health & Safety: “Cold Environments – Working in the Cold”NIOSH: Cold StressOSHA: Cold Stress Card