Cold Environmental Emergencies (HAP11)

Talk by Harvey Pynn

Notes by Tim Slade

“The Big Chill” Cold Environmental Emergencies and Drowning


  • Mild < 35oC
  • Severe <30oC

In cases of hypothermia causing cardiac arrest note the change in ALS guidelines below:

  • Only 3x shocks with temperature lower than 30°C

  • Timings of drugs which are normally 3-5 mins are doubled.

  • Need to re-warm early – active such as bypass or ECMO best in this scenario (where is your nearest ECMO centre?)

Cold Tips:

  • Blood gases are temperature dependent, so need to enter the correct temp on the instrument.
  • ECG changes for hyperkalemia can be obscured by cold,
  • Coagulation becomes grossly deranged when cold.
  • ECG may develop osbourne or j-waves .
  • Atropine and insulin ineffective.
  • Need to use a low reading thermometer – e.g. oesophageal because tympanic readings are inaccurate

Typical J Waves : from LITFL

 Summary of all ECG changes in hypothermia from LITFL

Options for re-warming:

  • Dry and wrap – likely to prevent further loss but not prevent warm up
  • Warmed O2
  •  Bair Hugger
  • Warmed bladder washout
  • Warm peritoneal lavage
  • Warmed fluid through chest drains
  • Most effective – bypass or ECMO


  • children
  • elderly
  • lean males
  • no head covering
  • malnourished
  • homeless
  • injured
  • poor equipment in harsh environments.

 Hypothermia links


  •  Superficial tissue e.g. cheeks in cold environments. Painless, numb, waxy appearance.
  • Areas need to be covered, not permanent.

Non Freezing cold injury (Trenchfoot):

  • Repeated exposure of feet to cold and wet, not a freezing injury
  • Acutely painful
  • Needs to be warmed and dried.


  • Caused by freezing of deep dermal tissues
  • Amputation often needed as part of treatment
  • Often not painful
  • Vasoconstriction leads to gangrene.


  • immersion in 40oC water
  • Treatment can be very painful, so plenty of analgesia
  • Aspirin

N.B. Do not warm up unless can keep warm as freeze-thaw-refreeze will cause more damage.




Types of drowning:

  1. Closed or dry drowning – secondary to larygnospasm with hypoxia.
  2. Open or wet drowning – secondary to water entering the lungs.

If a patient has been immersed in water, it is very important that they are extracted horizontally as if extracted upright likely that hydrostatic pressure will precipitate cardiac arrest.

HELP position is best position to conserve heat if you find yourself immersed in cold water awaiting rescue

The New England Journal Medicine “Drowning”  covers everything from pathophysiology to early intervention and treatment


Environmental Emergencies HAP 11
Environmental Emergencies HAP 11

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