Due to the high temperature conditions in many area of our country, I thought that this quick course in heat injuries is appropriate. Hopefully it will help some of you escape these conditions. I have had two of the three, Heat Cramps and Heat Exhaustion. And I can affirm that neither one are pleasant. I am indebted to armystudyguide.com for some of the information, and the format. Having been an EMT IV/D, during the summer, and especially during summer festivals, these conditions run rampant in the participants. Oh, the stories I can tell!
Types of Heat Injury:
Heat Cramps
Heat Exhaustion
Heat Stroke
Heat Cramps
Painful cramping of the larger muscle groups
legs, arms, abdomen
Causes
Due to excessive loss of salt through heavy sweating plus several hours of sustained exertion
Acclimatization decreases risk
Treatment
Heat Cramps
Get Patient to a 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 (MRE) plus fluid
Heat Exhaustion
Symptoms:
Heavy sweating, headache, light-headed, nausea/vomiting, tingling sensations
Temperature 99-104 F
Cause:
Dehydration plus excessive salt depletion
Treatment:
Get patient to a shaded environment
Loosen clothing
If suspect early heat stroke, treat as such
oral fluids if patient can drink
cold water, 0.1% salt solution, or 6% carbohydrate beverage
1-2 liters over 2-4 hours
EVAC to a treatment facility if available.
Heat Stroke
Symptoms:
Elevated temperature plus central nervous system disturbance.
Absence of sweating is a late finding.
Can begin as heat exhaustion and progress.
This is a dire emergency!
End-organ damage: brain damage, kidney failure, liver failure, blood clotting abnormalities
related to duration of elevated temperature
Treatment of Heat Stroke
ABC
An unconscious patient may vomit and aspirate
IV: no more than 2L unless circulatory collapse (shock)
Lower the body temperature as fast as possible!
Must take all clothes off
Cool water/rubbing alcohol with fanning...increase evaporation
Ice packs under groin and axilla
EVAC...open doors/windows in helicopter/vehicle
keep cooling to temp 101-102 F.
Ice-water immersion: controversial and unproven.
Risk Factors for Heat Stroke
Dehydration
Respiratory and GI illnessescausing dehydration is most common.
Alcohol use
Laxatives and diuretics
Medications that increase heat production and/or decrease heat loss:
pseudoephedrine, thyroid hormone, cocaine
Medications that decrease sweating:
antihistamines (Benadryl), anti-nausea (meclazine, phenergan)DietarySupplements:
Ephedrine (MaHuang), caffeine
Control Measures
Water and sports drinks
Salt
Acclimatization
OTSG Guidance for the Field Use of Sports Drinks:
Cool water is usually the best rehydration fluid.
Prolonged training and operational scenarios.
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
Sports Drink Recommendations:
INGREDIENT Amount per 8 ounces (as served)
Sodium 55-160 mg
Potassium 20-55 mg
Carbohydrate 11-19 gm
Acclimatization:
Physiologic adaptation that occurs in response to heat exposure in a natural environment.
Minimum of 5 days for most people
14 days required for 95% of population to have complete acclimatization.
One can deacclimatize as quickly!
Results of acclimatization:
Sweat threshold 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!
No comments:
Post a Comment