heat injuries. objectives l risk factors l types of heat injury *symptoms, cause and treatment l...
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OBJECTIVESOBJECTIVES
Risk Factors
Types of Heat Injury
*symptoms, cause and treatment Pre-hospital care
Management
Individual Risk FactorsIndividual Risk Factors
Poor fitness Large body mass Minor illness Drugs (cold/allergy/blood
pressure/performance enhancing) Highly motivated
Heat CrampsHeat Cramps Painful cramping of the larger muscle groups
legs, arms, abdomen
Due to excessive loss of salt through heavy sweating plus several hours of sustained exertion acclimatization decreases risk
Treatment shaded area massage arms/legs to increase circulation 0.1% salt solution orally (1/2 tsp salt in 1-qt. Water), sports
drink, or salted food plus fluids
Heat ExhaustionHeat Exhaustion Symptoms:
heavy sweating, headache, light-headed, nausea/vomiting, tingling sensations Temperature 99-104 F
Cause: dehydration plus excessive salt depletion
Treatment: shaded environment; loosen clothing If suspect early heat stroke, treat as such oral fluids if can drink
cold water, 0.1% salt solution, or 6% carbohydrate beverage 1-2 liters over 2-4 hours EVAC
Heat StrokeHeat Stroke
Symptoms: elevated temperature plus central nervous system
disturbance absence of sweating is a late finding
Can begin as heat exhaustion and progress End-organ damage:
brain damage, kidney failure, liver failure, blood clotting abnormalities
related to duration of elevated temperature
Treatment of Heat StrokeTreatment of Heat Stroke ABC
Unconscious patient may vomit and aspirate Keep patent airway IV: no more than 2L unless circulatory collapse
Lower the body temperature as fast as possible! All clothes off Cool water with fanning...increase evaporation Ice packs near groin or in the axilla EVAC...open doors/windows in vehicle keep cooling to temp 101-102 F.
Risk Factors for Heat StrokeRisk Factors for Heat Stroke
Dehydration Respiratory and GI illnesses most common Alcohol use Laxatives and diuretics
Medications Increase heat production and/or decrease heat loss
pseudoephedrine, thyroid hormone, cocaine
Decrease sweating antihistamines (Benadryl), anti-nausea (Phenergan)
Supplements Ephedrine (MaHuang), caffeine
Pre-Hospital CarePre-Hospital Care
Cooling is first priority Offer drink Drench with water Fan Massage large muscles Stop all measures if shivering occurs
Guidance for Sports DrinksGuidance for Sports Drinks
Cool water is usually the best rehydration fluid Prolonged training and participation
carbohydrates and electrolytes are also required for optimal physical and mental performance meals and snacks plus water are best
When sports drinks are appropriate: duration > 6 hours, hot weather, if snacks/meals not consumed duration > 3 hours, strenuous exercise, if snacks, meals not
consumed duration > 6 hours strenuous exercise, if total food intake is
significantly limited
Fluid Replacement GuidelinesFluid Replacement Guidelines Easy Activity
1 QT water per 2 hours Work:rest as needed
Moderate Activity 3 QT water per 4 hours Work:rest 40:20
Hard Activity 1 QT per hour Work:rest 30:30 more rest with increased RF
Do not consume >12 QT per day.
AcclimatizationAcclimatization Physiologic adaptation that occurs in response to heat exposure in
a natural environment 5 days for most 14 days required for 95% of population to have complete acclimatization. Can DE acclimatize as quickly
Results: sweat at lower temperature increased volume of sweat decrease in amount to salt secreted in sweat increased heat dissipation = lower core body temperature
End result: Decreased risk for heat injury!
Fluid Replacement for Warm Weather Fluid Replacement for Warm Weather
Heat Category
WBGT Index, °F
Easy Work Moderate Work Hard Work
Work /Rest
Water Intake,Qt/
h
Work /Rest
Water Intake,
Qt/h
Work /Rest
Water Intake,
Qt/h 1 78-81.9 NL ½ NL ¾ 40/20 min ¾ 2
(Green) 82-84.9 NL ½ 50/10 min ¾ 30/30 min 1
3 (Yellow
85-87.9 NL ¾ 40/20 min ¾ 30/30 min 1
4 (Red)
88-89.9 NL ¾ 30/30 min ¾ 20/40 min 1
5 (Black)
> 90 50/10 min 1 20/40 min 1 10/50 min 1
The work/rest times and fluid replacement volumes will sustain performance and hydration for at least 4 hours of
work in the specified heat category. Individual water needs will vary ± ¼ quart/hour. NL = no limit to work time per hour. Rest means minimal physical activity (sitting or standing) and should be accomplished in shade if possible.
Caution: Hourly fluid intake should not exceed 1½ quarts. Daily fluid intake should not exceed 12 quarts.