HYPOTHERMIA - Signs/Symptoms/Prevention & Mitigation

Hypothermia results when more heat is lost from the body than is produced (through metabolism and shivering) and retained (through body fat, clothing, and behavioural adaptation). Hypothermia is defined as core temp < 35 deg C. Every organ system is affected similar to multiple trauma. It is a medical emergency. Milder environments can also lead to hypothermia, depending on a person's age, body mass, body fat, overall health, and length of time exposed to cold temperatures.

Hypothermia symptoms for adults include:

• Shivering,

• Slow, shallow breathing

• Confusion and memory loss

• Drowsiness or exhaustion

• Slurred or mumbled speech

• Loss of coordination, fumbling hands, stumbling steps

• A slow, weak pulse

• In severe hypothermia, a person may be unconscious without obvious signs of breathing or a pulse

Treating Hypothermia

Little treatment is required for survivors who are shivering but are rational and capable of recounting events. In such event it is recommended that they remove wet cloths and switch to dry clothes, drink a hot sweet drink and rest in a room of room temperature. Always be aware that a survivor can become unconscious or collapse shortly after rescue. When a survivor is not shivering and is semi-conscious or unconscious, slow rewarming is essential. Rapid rewarming can be dangerous. The choice of rewarming technique is dependent on the severity of hypothermia.

Active external rewarming is used for people suffering from moderate hypothermia (core body temperature is between 28°C to 32°C). This involves a combination of heating blankets and using radiant heat from a light source or a forced heated air system. Heating blankets have been demonstrated to raise core temperature at a rate of 0.8°C an hour. Active internal rewarming techniques are the most rapid at raising core temperature. In the case of extracorporeal rewarming with cardiopulmonary bypass, the temperature can rise at a rate of 1°C to 2°C every 5 minutes.

Prevent Hypothermia

• Wear several layers of clothes rather than a single, thick layer. The best layers are those that provide good insulation and keep moisture away from the skin. Materials that do this include polyesters and wool. Wear an outer garment that is waterproof but will also "breathe."

• Arms close to sides of the chest, legs crossed & pulled up closing the groin area.

• In groups, keep still and close together in the huddle position.

• Wear a lifejacket and if possible a survival suit.

References

• Kasperson, R., Renn, O., Slovic, P., Brown, H., Emel, J., Goble, R., Kasperson, J. and Ratick, S. (1988). The Social Amplification of Risk: A Conceptual Framework. Risk Analysis, 8(2), pp.177-187.
• Aven, T., Vinnem, J. and Wiencke, H. (2007). A decision framework for risk management, with application to the offshore oil and gas industry. Reliability Engineering & System Safety, 92(4), pp.433-448.
• Insurance technology and soceity, (2014). Insurance technology and soceity. [online] Available at: https://insurancetechnologyandsoceity.wordpress.com/ [Accessed 27 Jul. 2015].
• Mayoclinic.org, (2015). Hypothermia - Mayo Clinic. [online] Available at: http://www.mayoclinic.org/diseases-conditions/hypothermia/basics/definition/con-20020453 [Accessed 27 Jul. 2015].
• http://www.hypothermia.org/inwater.htm

https://www.gov.uk/government/uploads/system/uploads/attachment_data/file/285619/mcga-shs_capt_guide_chap11.pdf