Vehicular Hyperthermia

HyperthermiaUnquestionably, automobiles pose a significant health risk for both adults and children.  Trauma related to car collisions are a leading cause of morbidity and mortality in children. Obviously this deserves much attention (Injury Prevention, Childhood Injury), but let us not forget that cars can present various other hazards for children. With the oppressive heat of summer dominating our days, let’s consider Vehicular Hyperthermia.

 

Hyperthermia: Contemplations for Kids

  • Children are in the group of people who are at greatest risk for heat-related illness.
  • Commonly cited reasons for this increase risk:
    • Greater body-surface to mass ratio – adversely affects heat absorption
    • Higher metabolic rate – kids generate more heat
    • Lower perspiration rate – decreased heat dissipation
    • Reduced acclimatization – adjust more slowly to environmental exposures
  • Whether these traits truly influence a child’s susceptibility to heat exposure is debated. [Marshall, 2010; Rowland, 2008]
  • What is known is that kids interact with their environment differently than adults.
    • Older children, often don’t appreciate the danger their actions place them in (i.e., testosterone-laden teenage boys).
    • Young children are dependent upon adults to keep them out of danger.
  • Metabolic processes constantly generate heat.
    • At rest, the body generates enough heat to raise the body temperature ~1 degree C/hr.
  • Environment also influences the body’s temperature.
    • When the ambient temperature exceeds the body’s, there is heat gain.
    • Heat injury occurs when the body’s temperature rises faster than it can dissipate the heat.

 

Vehicular Hyperthermia

  • Despite numerous public service announcements (ex, kidsandcars.org, hyperthermia is still the leading cause of noncrash-related child mortality due to cars. [NHTSA.org]
  • While the greatest risk is during summer months, it can occur year round. [Grundstein,  2015; Duzinski, 2014]
    • The inside of the car can reach critical temperatures even during cold days. [Grundstein,  2015]
    • In an infant model used to measure body temperature in a closed car, heat stroke temps were reached: [Grundstein,  2015]
      • in hot months (28 C), in 105 min
      • in mild months (17 C), in 200 min
      • in cold months (1 C), in 315 min

 

Hyperthermia Treatment

  • The best treatment is prevention!
    • Always take simple opportunities to remind people of hazards that exist (ex, Detergent Pods, Lawn mowers)
    • A sleeping infant can be easily forgotten by a overworked, exhausted, mentally distracted parent running a simple errand. Reminders of this can be powerful!
  • ABC stabilization
  • Cool the patient
    • Spray the skin with room-temperature water.
    • Direct electric fans onto the skin.
    • Do not apply ice water widely to the body surface (may cause vasoconstriction)
    • Ice packs to groin and axilla can be used.
    • Invasive lavage is not currently recommended.
    • Cooling blankets can be useful if available.
  • Monitor core temperature
    • Active cooling should be continued until temp is <39 degrees C.
  • Hydrate with isotonic fluids
  • Anticipate and treat complications
    • Heatstroke affects all organ systems.
    • Keep rhabdomyolysis on your Ddx.
    • Transaminase levels correlate well with severity of injury and peak in 24-48 hrs.
    • Monitor glucose levels closely. (Don’t let hypoglycemia fool you!!)
    • Monitor coagulation studies to look for DIC.
  • Some patients may benefit from venous-venous hemofiltration [Zhou, 2011]

 

References

Grundstein AJ1, Duzinski SV, Dolinak D, Null J, Iyer SS. Evaluating infant core temperature response in a hot car using a heat balance model. Forensic Sci Med Pathol. 2015 Mar;11(1):13-9. PMID: 25332172. [PubMed] [Read by QxMD]

Mutter L, Meredith M. Perils of SUMMER. How to treat pediatric summertime emergencies. JEMS. 2015 Jul;40(7):38-44; quiz 44. PMID: 26364424. [PubMed] [Read by QxMD]
Duzinski SV1, Barczyk AN1, Wheeler TC2, Iyer SS3, Lawson KA1. Threat of paediatric hyperthermia in an enclosed vehicle: a year-round study. Inj Prev. 2014 Aug;20(4):220-5. PMID: 24246714. [PubMed] [Read by QxMD]

Zhou F1, Song Q, Peng Z, Pan L, Kang H, Tang S, Yue H, Liu H, Xie F. Effects of continuous venous-venous hemofiltration on heat stroke patients: a retrospective study. J Trauma. 2011 Dec;71(6):1562-8. PMID: 22182867. [PubMed] [Read by QxMD]

Marshall SW1. Heat injury in youth sport. Br J Sports Med. 2010 Jan;44(1):8-12. PMID: 19858115. [PubMed] [Read by QxMD]

Rowland T1. Thermoregulation during exercise in the heat in children: old concepts revisited. J Appl Physiol (1985). 2008 Aug;105(2):718-24. PMID: 18079269. [PubMed] [Read by QxMD]

Gibbs LI1, Lawrence DW, Kohn MA. Heat exposure in an enclosed automobile. J La State Med Soc. 1995 Dec;147(12):545-6. PMID: 8543892. [PubMed] [Read by QxMD]

Wagner C1, Boyd K. Pediatric heatstroke. Air Med J. 2008 May-Jun;27(3):118-22. PMID: 18456172. [PubMed] [Read by QxMD]
Jokinen E1, Välimäki I, Antila K, Seppänen A, Tuominen J. Children in sauna: cardiovascular adjustment. Pediatrics. 1990 Aug;86(2):282-8. PMID: 2371104. [PubMed] [Read by QxMD]

Sean Fox

I enjoy taking care of patients and I finding it endlessly rewarding to help train others to do the same. I trained at the Combined Emergency Medicine and Pediatrics residency program at University of Maryland, where I had the tremendous fortune of learning from world renown educators and clinicians. Now I have the unbelievable honor of working with an unbelievably gifted group of practitioners at Carolinas Medical Center. I strive every day to inspire my residents as much as they inspire me.

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