From the Guidelines
Treatment for hypothermia should focus on rewarming the body safely while supporting vital functions, with the approach varying based on the severity of hypothermia, as outlined in the most recent guidelines 1. For mild hypothermia (body temperature 32-35°C), passive rewarming with dry clothing, blankets, and a warm environment is often sufficient.
- Key considerations include:
- Removing wet clothing to prevent further heat loss
- Providing a warm environment to support the body's natural rewarming process
- Monitoring vital signs and core temperature closely
- For moderate to severe hypothermia (below 32°C), active rewarming techniques are necessary, which may include:
- External active rewarming methods such as applying heating blankets, warm water immersion, or forced warm air systems
- Internal active rewarming methods such as warm IV fluids (warmed to 40-42°C), warm humidified oxygen, peritoneal lavage with warm fluids, or extracorporeal blood warming in critical situations
- Throughout treatment, careful monitoring of vital signs, cardiac rhythm, and core temperature is essential as rewarming can cause arrhythmias or "rewarming shock" from peripheral vasodilation, as noted in earlier guidelines 1.
- Severe cases require management of complications like cardiac arrhythmias, respiratory support, and correction of metabolic abnormalities, with an emphasis on handling patients gently to prevent triggering arrhythmias and removing wet clothing immediately, as recommended in first aid guidelines 1.
- Rewarming should proceed at a controlled rate, typically 0.5-2°C per hour depending on severity, to prevent complications from too-rapid temperature changes, aligning with the principles outlined in more recent first aid guidelines 1.
From the Research
Treatment Approaches for Hypothermia
The treatment of hypothermia can be categorized into different approaches, including:
- Passive external rewarming: This method involves removing wet clothing, providing a warm environment, and using blankets to trap body heat 2.
- Active external rewarming: This method involves using warm water bottles, heating pads, or warm compresses to increase blood flow and warm the body 2.
- Active core rewarming: This method involves using techniques such as peritoneal lavage, hemodialysis, or cardiopulmonary bypass to directly warm the core of the body 3, 4, 5.
- Rewarming using warm intravenous fluids: This method involves infusing warm fluids into the body to increase the core temperature 6.
Rewarming Techniques
Different rewarming techniques have been studied and compared, including:
- Hemodialysis: This technique has been shown to be effective in rewarming patients with severe hypothermia, with average rewarming rates of 1.5°C/hour 3.
- Peritoneal lavage: This technique has been shown to be effective in rewarming patients with severe hypothermia, and can be used in nearly every hospital if the necessary equipment is available 4.
- Cardiopulmonary bypass: This technique is considered the treatment of choice for active internal rewarming of patients with severe hypothermia, but it is not always available and is time-consuming to initiate 3.
- Direct blood warming: This technique has been shown to be one of the most effective rewarming techniques, based on thermodynamic analysis of rewarming 6.
Important Considerations
When treating hypothermia, it is important to consider the following factors:
- Initial core temperature: This is an important prognostic factor, with lower temperatures associated with higher mortality rates 3.
- Ambient temperature: This can affect the rewarming rate and should be taken into account when selecting a rewarming technique 6.
- Patient's own heat production: This can affect the rewarming rate and should be taken into account when selecting a rewarming technique 6.
- Effects of anesthesia and paralytic agents: These can affect the rewarming rate and should be taken into account when selecting a rewarming technique 6.