Module 4 Flashcards
Heat Stress
- Heat Exhaustion
- Heat Stroke
Fluids and Salts
- Hyponatremia
- Dehydration
Exertion
-Rhabdomyolysis
Challenges with Exertion and Heat Illnesses
-Vague Symptoms ~Nausea ~Vomiting ~Weakness ~Dizziness ~Syncope -Big differential diagnosis can make management priorities challenging
Narrowing it Down
- Detailed History
- Especially regarding fluid and nutritional intake, and urination
- Consider the environment and activities leading up to the illness
Hyperthermia and Heat Related Illness
-Hyperthermia is not a fever
-Heat Gained > Heat Lost
~Production over accumulation
~Exercise
~Metabolism
~Environment
~Respiration
~Vasodilation
*Blood vessels opening up
~Perspiration
Body’s Response to Heat
-Vasodilation ~Increased blood flow to skin ~Flushed appearance -Increased Cardiac Output ~Faster heart rate -Increased Sweating ~Depletes salt and water -Increased Anti-Diuretic hormone (ADH) ~Prevents urination
Risk Factors
Obese ~70% relative risk for heat illness among US army recruits -Unfit -Dehydrated -Previous Hx of Heat stroke -Cardiovascular disease, diabetes, etc. -Not acclimated to heat -Medication ~Diuretics ~Anticholinergics ~Vasodilators ~Antihistamines ~Sedatives ~B-blockers
Heat-related Illness (Occur at Normothermia)
-Heat Edema
-Heat Rash (miliaria rubra)
-Heat Cramps
-Heat Syncope
~All Non-emergent
*Oral rehydration
*Passive Cooling
*Remove from heat
*Elevate extremities
*Electrolyte Replacement
-Heat Exhaustion
~Possible risk for progression
Heat Stroke
-True Emergency!!
-Core body temp. greater than 104F
-Presents with CNS abnormalities
-Altered mentation, seizures, coma
-Sweating?
~DO NOT use the presence of sweating to argue against heat stroke
-Prognosis
-Directly related to magnitude and duration of heat stroke
-Mortality 10%
-Up to 33% if associated with hypotension
Management of Hyperthermia
-ABCs
-Remove from heat source
-Begin active cooling
~Cold water immersion
~Cold pack
~Convective cooling
-Hydration
Heat Conditioning
-Good for heath
-Prevents heat illness
~Increases plasma volumes
~Increases sweating with reduced salt depletion
~Promotes heat shock proteins
Exercise Associated Hyponatremia (EAH)
-Low sodium in the blood
-Less a problem of salt than it is water
~Dilutional hyponatremia
~Water Toxicity
-“If you’re thirsty, you’re already dehydrated”
~Is not exactly true can cause hyponatremia if over hydrated
Pathophysiology of EAH
-Behavioral Factors ~Drinking too much water ~Afraid of becoming dehydrated -Environmental/Physical Factors ~Heat and physical stress increase ADH ~Accumulation for free water
Recognition of hyponatremia
-History of drinking excessive water
-Mild Symptoms
~Headache, agitation, thousand yard stare, nausea& vomiting, little or no urine output, lethargy, thirsty, paranola, impeding doom
-Severe Signs and Symptoms
~Seizure
~Altered Mentation
~Coma/death
Treatment of Hyponatremia
-Remove from heat and cool them down
-Calm them down
-Consider oral hypertonic solution
~No group difference was noted in the primary outcome measure of change in blood {Na+} over 60 min of observation following a 100mL bolus of either oral or IV 3% saline
-For mild, be patient
-For severe, immediate evacuation & ALS care
Dehydration
-Fluid intake < fluid loss
-Most fluid loss results from thermoregulatory sweating
~Insensible loss = respiration, can be as much as 1-1.5 liters/hour at high altitudes
-Dehydration has a significant impact on exercise performance and thermoregulation
~2% or greater of body weight
-During exercise, sweat rates vary from 0.5 to 2 liters/hour
Complications of Dehydration
- Decreased renal blood flow = prerenal injury
- Decreased blood flow to muscles
- Decreased cardiac output
- Decreased cutaneous blood flow and decreased sweating = greater heat accumulation
- Increased osmolality = cellular dehydration
Signs and Symptoms of Dehydration
- Weakness/Dizziness
- Nausea and Vomiting
- Increased Thirst
- Dry oral mucosa
- Decreased urine output, darkened urine
- Decreased body weight
Prevention and treatment of Dehydration
-Insure proper hydration Before activity
-During activity, maintain hydration
~Drink to thirst
~Fluid absorption occurs at around 450-700 mL per hour
~Ensure sodium, potassium, and carbohydrate intake
-Hydrate after activity with meals
-Manage with PO fluids, PO fluids should be mixed to taken with food
Rhabdomyolysis
-Skeletal muscle injury causes intracellular substances to be dumped into the blood stream
Rhabdo Causes
- Drugs/Toxins
- Trauma
- Seizures
- Strenuous Exercise
- Dehydration
- Heat Illness
- Electrical injury
- Crush injury
Complication of Rhabdo
- Renal Failure
- Electrolyte Abnormalities
- Compartment Syndrome
Clinical Features of Rhabdo
-PUMP ~Pain of the affected muscle group ~Urine *Decrease and/or darkened ~Myalgia *Muscle soreness ~Physical exertion -Muscle cramping
Management of Rhabdo
- Discontinue exercise
- Hydrate
- Keep them cooled down
- Evacuate
- More hydration
How We Get Cold
-Radiation ~Heat loss -Evaporation ~Dampness -Conduction ~Cold water -Convection ~Winds
What Will Impair Thermoregulation?
- Tight fitting clothing
- Smoking
- DM/PVD Hypovolemia
- Head Injury
- Neoplasm
- Sepsis
Characteristics of the Three Zones of Hypothermia
- Mild
- Moderate
- Severe
Mild hypothermia
-Core Temp ~35.0 C to 33.0C ~95.0 F to 91.4F -Shivering thermogenesis starts -Ataxia and apathy develop
Moderate Hypothermia
-31.0C or 87.8
~Shivering thermogenesis stops
-29.0C or 85.2
~Bradycardia, pupils dilated; paradoxical undressing
-28.0C or 82.4
~Decreased ventricular fibrillation threshold; loss of reflexes and voluntary motion
Severe Hypothermia
-28.0C or 82.2F ~Ventricular Fibrillation -18.0C or 64.4 ~Asystole -16.0C or 60.8 F ~Lowest adult accidental hypothermia survival -15.2C or 59.2 ~Lowest infant accidental hypothermia survival -9.0C or 48.2F ~Lowest therapeutic hypothermia survival
Hypothermia and Trauma
- Impact on mortality is clear
- 100% of trauma patients with a core temp. <89.6F died, and only 3% died who had core temp. >89.6F
- Hypothermia is an independent predictor of mortality (11 fold if <89.6F
Renal System
- Peripheral vasoconstriction with central shift of blood
- Diuresis ensure despite hypovolemia
- Diuresis triples with alcohol
Ethanol (alcohol)
- Impairs Thermoregulation
- Peripheral Vasodilation
- Impairs behavioral Adaptation
Mild/Moderate Treatment
-Recognition… Wide Spectrum
-Prevent heat loss
-Remove wet clothing, put on dry
-Calories
-Hypothermia wrap +/- heat is okay
~Warm water bottles, body to body, etc.
-“Feed em and beat em?”
~Pretty dangerous method if get them moving too early
Hypothermia Wrap
- Tarp
- Sleeping Pad
- Sleeping Bag
- Patient in hat and warm dry clothes in sleeping bag WITH hot bottle
- Another sleeping bag
- Wrap the tarp up
Severe Hypothermia Treatment
- Comatose victims require carful handling
- Sensitive to VF/asystole
- Treatment should be aimed at preventing further heat loss and evacuation
- Assume irritable myocardium, hypovolemia, large temp, gradient between periphery and core
- Replace wet clothing
- “You are not dead unless you are warm and dead”
Risk Factors of Lightning Injuries
- Male sex
- 64% deaths outdoor leisure
- 15% during outdoor work
- 92% May-Set.
- 73% afternoon/early evening
