1. Heat Emergencies Prepared by: Steven Jones, NREMT-P

2. Thermoregulation Homeostasis requires stable temperature ~98.6ºF Control mechanism Hypothalamus Peripheral thermoreceptors Balance between heat production, heat loss

3. Heat Production Metabolism Voluntary large muscle movement Shivering

4. Heat Induced Illness Results from: Increase in body temperature outside normal range Prolonged efforts to compensate; profuse sweating Dehydration

5. Hyperthermia Caused by Overwhelmed thermoregulatory system Environmental conditions (exogenous) Excessive exercise (endogenous) Excessive clothing Drugs ? ? Methamphetamines are notorious for causing a rapid ↑ in body temperature Failure of thermoregulatory system CVA

6. Heat-Related Illness Heat Cramps Heat Exhaustion Heat Stroke

7. Heat Cramps

8. Pathophysiology Hot environment causes profuse sweating Na + (sodium) lost in sweat Lack of Na + causes muscle cramping

9. Heat Cramps Signs/Symptoms Patient usually in good condition; working in hot, humid environment Cramps of fingers, arms, legs, abdominal muscles Nausea Normotensive, mild hypotension Tachycardia Cool, pale skin Awake, alert, normal body temperature

10. Heat Cramps Management Move to cool place, rest, lie down Give balanced salt/water solution (Electrolyte Solution) Salt alone leads to increased nausea, increased water loss Water alone leads to worsened cramping (dilutional hyponatremia)

11. Heat Cramps Management IV NaCl if patient too nauseated to drink Avoid massaging muscles Avoid activity Increase fluid, Na+ intake

12. Heat Exhaustion

13. Pathophysiology Increased vascular space due to vasodilation Decreased blood volume due to sweating Decreased CNS perfusion

14. Heat Exhaustion Epidemiology People working in hot, humid environments Elderly, due to decreased thirst mechanism Hypertensives, due to medication effects

15. Heat Exhaustion Signs/Symptoms Headache, dizziness, fatigue, nausea, confusion Weakness, syncope Profuse perspiration, pallor Tachycardia, hypotension, tachypnea Orthostatic changes Normal core temperature

16. Heat Exhaustion Management Move to cool place, stop activity, lie down Supine, legs elevated Sponge with cool water, fan Balanced salt/water (electrolyte) solution, or IV with NaCl, if too nauseated to drink Assess glucose if altered mental status

17. Heat Exhaustion Management Transport indicated if: Loss of consciousness occurs Underlying cardiovascular disease Oxygen, EKG monitor if transport indicated

18. Heat Stroke

19. Altered LOC + Hot Environment = THINK - Heat Stroke

20. Heat Stroke Pathophysiology Body heat accumulation leads to increased temperature above 106 0 F Increased temperature damages hypothalamus: Heat regulating mechanism failure occurs 25 - 50% mortality in elderly

21. Types of Heat Stroke Exertional Heat Stroke Occurs in healthy, young people in hot environments Heat builds up faster than it is removed Damage to hypothalamus occurs Patient sweats heavily

22. Types of Heat Stroke Classic Heat Stroke Elderly, alcoholics, obese, heart disease patients, phenothiazine users Body heat builds up slowly over several days Dry skin, absence of sweating

23. Heat Stroke Signs/Symptoms Headache, dizziness, irritability Decreased LOC, seizures Bounding pulse progressing to rapid, weak pulse Hypotension secondary to vasodilation Presence or absence of sweating is NOT a reliable sign

24. Heat Stroke Management Secure airway High concentration oxygen Rapid cooling to 102 0 F IV NaCl Avoid volume in classic heat stroke Exertional heat stroke may need volume replacement Monitor EKG

25. Heat Stroke Management Drugs as necessary Glucose for hypoglycemia Diazepam for seizures, PRN Reassess for secondary complications Cardiac dysrhythmias Pulmonary edema Rapid Transport

26. Heat Emergencies