Heat stroke medical therapy

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Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]; Associate Editor(s)-in-Chief: Usama Talib, BSc, MD [2]

Overview

The heat stroke is primarily managed by removing the patient from the environment to minimize heat exposure and to ionitiate rapid cooling protocols.[1]

Medical Therapy

The heat stroke is primarily managed by:[1][2][3][4][5]

  • Removing the patient from the environment to minimize heat exposure
  • Initiating cooling protocols as soon as possible
  • Providing support to the effected organs
The Management of Heat Stroke*
Condition Intervention Goal
Out of Hospital
Heat stress (due to heat wave, summer

heat, or strenuous exercise), with

changes in mental status (anxiety,

delirium, seizures, or coma)

  • Measure the patient’s core temperature (with a rectal probe)
  • If the core temperature is >40°C, move the patient to a cooler place, remove his or her clothing, and initiate external cooling:
    • Cold packs on the neck, axillae, and groin;
    • Continuous fanning (or opening of the ambulance windows)
    • Spraying of the skin with water at 25°C to 30°C
  • Position an unconscious patient on his or her side and clear the airway
  • Administer oxygen at 4 liters/min
  • Give isotonic crystalloid (normal saline)
  • Rapidly transfer the patient to an emergency department
  • Diagnose heat stroke†
  • Lower the core temperature to <39.4°C, promote cooling by conduction, and promote cooling by evaporation
  • Minimize the risk of aspiration
  • Increase arterial oxygen saturation to >90%
  • Provide volume expansion
In Hospital
Cooling period Confirm diagnosis with thermometer calibrated to measure high temperatures (40°C to 47°C).
Hyperthermia Monitor the rectal and skin temperatures; continue cooling Keep rectal temperature <39.4°C§ and skin

temperature 30°C–33°C

Seizures Give benzodiazepines Control seizures
Respiratory failure Consider elective intubation (for impaired gag and cough reflexes or deterioration of respiratory function) Protect airway and augment oxygenation (arterial

oxygen saturation >90%)

Hypotension Administer fluids for volume expansion, consider vasopressors, and consider monitoring central venous pressure Increase mean arterial pressure to >60 mm Hg

and restore organ perfusion and tissue oxygenation

Rhabdomyolysis Expand volume with normal saline and administer intravenous

furosemide, mannitol, and sodium bicarbonate

Prevent myoglobin-induced renal injury: promote

renal blood flow, diuresis, and alkalization

of urine

Monitor serum potassium and calcium levels and treat hyperkalemia Prevent life-threatening cardiac arrhythmia
After cooling
Multiorgan dysfunction Supportive therapy Recovery of organ function

*Adopted from Heat Stroke.[3]

Cooling

The cooling is done on the following principles:[4][6]

  • The heat is transferred from the body core to the skin and then dissipated into the air.
  • Vasodilatation of the vessels in the skin occurs as a compensatory mechanism to help dissipate the heat
  • Cooling therapies focus on increasing and facilitating the transfer of heat from the body to the surroundings while keeping the vasodilatory cooling mechanism intact. They can utilize:
    • Increasing the gradient of temperature between the body and the surroundings (cooling by the help of conduction)
    • Increasing the water vapor pressure gradient between the body and the surroundings (cooling by the help of evaporation)
    • Accelerating the flow of air closer to the skin (cooling by the help of convection)
  • These can be achieved by:
    • Application of water
    • Application of ice
    • Fanning

Methods of Cooling

Methods of Cooling*
Techniques based on Conductive cooling
External
  • Cold-water immersion
  • Application of cold packs or ice slush over part of the body or the whole

body

  • Use of cooling blankets
Internal
  • Iced gastric lavage
  • Iced peritoneal lavage
Techniques based on Evaporative or Convective cooling
  • Fanning the undressed patient at room temperature (20°C to 22°C)
  • Wetting of the body surface during continuous fanning
  • Use of a body-cooling unit

*Adopted from Heat Stroke.[3]

Avoidance of Excessive cooling

Most of the techniques used for cooling can decrease the temperature of the skin excessively. Temperature can fall up to 30°C or lower resulting in compensatory mechanisms like:[3]

These responses are not desired and can result in inappropriate management of hyperthermia. This can be avoided by an alternate or combined application of the following along with the cooling techniques:[7][8]

  • Massaging of the body
  • Spraying lukewarm water of 40°C
  • Exposing to moving air which is hot i.e around 45°C

Cooling Rates

  • A decrease in temperature at the rate of 0.15°C or 0.27°F per minute has been successfully tested.[9]

Use of Pharmacological Agents

Pharmocological agents have not proven to be of benefit in case of hyprethermia or heat stroke. The agents that have been considered include:[10][11][12]

Recovery

The revival of the functioning of the central nervous system is a positive prognostic sign. It is usually seen following aggressive therapy. 20% patients face residual damage of the brain and a higher mortality is associated with this.[13][5]

References

  1. 1.0 1.1 Leon LR, Bouchama A (2015). "Heat stroke". Compr Physiol. 5 (2): 611–47. doi:10.1002/cphy.c140017. PMID 25880507.
  2. Bouchama A, Dehbi M, Mohamed G, Matthies F, Shoukri M, Menne B (2007). "Prognostic factors in heat wave related deaths: a meta-analysis". Arch Intern Med. 167 (20): 2170–6. doi:10.1001/archinte.167.20.ira70009. PMID 17698676.
  3. 3.0 3.1 3.2 3.3 Bouchama A, Knochel JP (2002). "Heat stroke". N Engl J Med. 346 (25): 1978–88. doi:10.1056/NEJMra011089. PMID 12075060.
  4. 4.0 4.1 Graham BS, Lichtenstein MJ, Hinson JM, Theil GB (1986). "Nonexertional heatstroke. Physiologic management and cooling in 14 patients". Arch Intern Med. 146 (1): 87–90. PMID 3942468.
  5. 5.0 5.1 Dematte JE, O'Mara K, Buescher J, Whitney CG, Forsythe S, McNamee T; et al. (1998). "Near-fatal heat stroke during the 1995 heat wave in Chicago". Ann Intern Med. 129 (3): 173–81. PMID 9696724.
  6. Rowell LB (1983). "Cardiovascular aspects of human thermoregulation". Circ Res. 52 (4): 367–79. PMID 6339107.
  7. WYNDHAM CH, STRYDOM NB, COOKE HM, MARITZ JS, MORRISON JF, FLEMING PW; et al. (1959). "Methods of cooling subjects with hyperpyrexia". J Appl Physiol. 14: 771–6. PMID 13846292.
  8. Al-Aska AK, Abu-Aisha H, Yaqub B, Al-Harthi SS, Sallam A (1987). "Simplified cooling bed for heatstroke". Lancet. 1 (8529): 381. PMID 2880179.
  9. Bouchama A, Dehbi M, Chaves-Carballo E (2007). "Cooling and hemodynamic management in heatstroke: practical recommendations". Crit Care. 11 (3): R54. doi:10.1186/cc5910. PMC 2206402. PMID 17498312.
  10. Bouchama A, Cafege A, Devol EB, Labdi O, el-Assil K, Seraj M (1991). "Ineffectiveness of dantrolene sodium in the treatment of heatstroke". Crit Care Med. 19 (2): 176–80. PMID 1989755.
  11. Channa AB, Seraj MA, Saddique AA, Kadiwal GH, Shaikh MH, Samarkandi AH (1990). "Is dantrolene effective in heat stroke patients?". Crit Care Med. 18 (3): 290–2. PMID 2302955.
  12. Hadad E, Cohen-Sivan Y, Heled Y, Epstein Y (2005). "Clinical review: Treatment of heat stroke: should dantrolene be considered?". Crit Care. 9 (1): 86–91. doi:10.1186/cc2923. PMC 1065088. PMID 15693989.
  13. Hart GR, Anderson RJ, Crumpler CP, Shulkin A, Reed G, Knochel JP (1982). "Epidemic classical heat stroke: clinical characteristics and course of 28 patients". Medicine (Baltimore). 61 (3): 189–97. PMID 7078400.

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