1. Sunrise over Gulf of Mexico

2. Heat Illness and Heat Stroke
Inability to maintain normal body temp due to excess heat production or decreased heat transfer to environment

3. 3 Forms of Heat Illness Heat Stress Heat Exhaustion Heat Stroke
Feeling of discomfort, decreased Performance
Normal body temp
Heat Exhaustion
Mild dehydration
Temp – 104
Intense discomfort, thirst, N/V
Transient confusion (No other neuro symptoms)
Heat Stroke
Body temp >104
Neuro dysfunction

4. Heat Stroke Classic (nonexertional) Exertional
Environmental exposure to heat
Young children, elderly, disabled
Exertional
Young, healthy individuals
Athletes, military recruits
Heavy exercise in high temps and humidity

6. Heat Stroke
Among high school athletes, heat stroke is 3rd leading cause of mortality
May ignore symptoms until they collapse
Risk factors: prolonged exercise in warm, humid environment

7. Physiologic Cooling Mechanisms
Evaporation (of sweat)
Ineffective relative humidity >75%
Convection, conduction, and radiation
Ineffective >95F

9. Much more than little adults
Children are at increased risk for heat illness
Higher metabolic rate- higher heat production
Increased surface area to mass ratio- increased absorption of heat
Smaller absolute blood volume and lower cardiac output- limits transfer of heat from core to surface
Lower sweat rate per gland and start at higher temps
Inadequate fluid replenishment
Longer to acclimate to hot environments (10-14days)

10. Critical Thermal Maximum (CTM)
Degree of elevated body temp and duration that can be tolerated b/f cell damage occurs
Core body temp for 45min

11. DDx Sepsis/Encephalitis CNS Conditions (Dysregulation)
Congenital anomalies or traumatic brain injury
Status Epilepticus
Toxidromes
Anticholinergics, Salicylate, Stimulants
Serotonin Syndrome
Neuroleptic Malignant Syndrome
Malignant Hyperthermia
Thyroid Storm
Hemorrhagic Shock and Encephalopathy Syndrome

12. Stabilization ABCDE Continuous temp monitoring (rectal probe)
Rapid Cooling
Evaporative cooling of greatest benefit
Spray with water while using high-flow fans
Can decrease temp by 0.27F/min
Ice packs to neck, axillae, groin as adjunct
Cooling blankets not as beneficial
Cold water immersion is effective but not practical
Chilled IV saline (little data)

13. Cooling Bring temp down to <104F as rapidly as possible
Stop cooling measures at 100.4F
Use benzos to stop shivering

14. Treatment of End Organ Dysfunction
Rhabdomyolysis
hyperkalemia, hypocalcemia, hyperphosphatemia
DIC
Acute Renal Failure
Hyponatremic dehydration/ Hypovolemic shock
Cardiogenic shock
Pulmonary edema
Liver failure
Cerebral Edema

15. Outcome Mortality Permanent neurologic damage t>107.6
Up to 15% in adolescents
Up to 63% in elderly
Permanent neurologic damage t>107.6
Heat Intolerance

16. Prevention Infants: avoid excessive bundling or bedding
If sweating at night- dangerous sign
Lightly colored vehicle with window cracked:
145F in 40minutes
Keep parked cars locked
Increased awareness to high risk groups

17. Sporting Events Light colored clothing
Never wear material that restricts sweat loss
500ml within 2hrs prior to event
250ml q 20 minutes while exercising