EMS A to Z: Cold Related Illness

Show Notes:

From your hosts, Dr. Josh Gaither, Dr. Amber Rice, and Dr. Rachel Munn

Let’s break the group of “cold-related illnesses” down, because it contains more than just hypothermia... 

1. Hypothermia
2. Frostbite / frost nip
3. Freezing injury to the tissues (facial structures, extremities)
4. Degrees can be estimated, like burns, once thawing / rewarming has occurred
5. Chillblains
6. Capillary damage from repeated exposure to cold temperatures / wind
7. Trench foot / immersion foot 
8. Non-freezing tissue injury due to feet being continually exposed to moisture and cool temperatures 
9. Carbon monoxide poisoning 

What temperature actually defines hypothermia?  

• Hypothermia is a core body temperature < 35C (95F)
• There are degrees of hypothermia based on temperature and symptoms
• With mild hypothermia, the patient still maintains some temperature regulatory mechanisms, like shivering, but may have confusion and vital sign abnormalities
• With moderate hypothermia, thermoregulation is less effective and cardiac dysrhythmias can begin to occur
• In severe hypothermia, coma can occur with severely aberrant vital signs and arrhythmias
• Often resuscitation / defibrillation is ineffective until rewarming can occur 

How do we manage these patients?  

• The WMS published recommendations with an update in 2019 (https://www.wemjournal.org/article/S1080-6032(19)30173-5/fulltext).
• The key factors are identifying the degree of hypothermia expected based on patient presentation and initiating treatments:
• Rewarming
• Remove from the cold environment
• Remove wet clothing / wrap with foil blanket, layers
• Calorie replacement
• Shivering uses a lot of energy
• Fluid replacement
• Cold induced diuresis can occur and patients can become volume down
• CPR/resuscitation/airway management if indicated
• Interestingly if the temperature is measured < 30C, only one shock is advised for VF and no vasoactive drugs until > 30C

Although we frequently think of exposure related hypothermia, non-environmental hypothermia can occur:

• Recall that hypothermia can occur in ill or injured patients even if the ambient temperature is quite warm.
• Patients with critical illness or sepsis, particularly the elderly, can lose their ability to thermoregulate and have hypothermia rather than fever in response to their illness.
• On a recent shift I had two patients with DKA who were very sick and both hypothermic, even without exposure to a cold environment. 
• Our trauma patients are also at risk of developing hypothermia, which is part of the trauma triangle of death, and should be prevented or treated aggressively. 

What about carbon monoxide poisoning? 

• Carbon monoxide exposure / poisoning rises in colder months when individuals are using indoor heat.
• Indoor propane or other gas heaters are risky. 
• Carbon monoxide is odorless and tasteless, making it difficult to detect without functioning carbon monoxide alarms (which aren’t cheap).
• Symptoms may include headache, dizziness, weakness, nausea, vomiting, confusion, progressing to coma and death due to asphyxia.
• If an entire family (or pets) are all experiencing symptoms, this should be on your radar! 
• Carbon monoxide binds to hemoglobin in place of oxygen; this is why standard pulse oximeters are inaccurate in carbon monoxide poisoning. 
• Patients should be transported to the hospital and provided supplemental oxygen.
• Supplemental O2 increases the rate at which carbon monoxide is cleared from the body.
• Some patients may benefit from hyperbaric therapy.