From the Guidelines
Hypothermia is categorized into four stages: cold stress (35-37°C), mild hypothermia (32-35°C), moderate hypothermia (28-32°C), and severe hypothermia (below 28°C), with each stage presenting distinct signs and symptoms. The stages of hypothermia are characterized by a range of clinical manifestations, from mild to severe, and are crucial in determining the appropriate treatment approach.
Stages of Hypothermia
- Cold stress (35-37°C): characterized by alertness and possible shivering, with passive rewarming often being adequate in healthy individuals 1.
- Mild hypothermia (32-35°C): presents with altered level of responsiveness and shivering, requiring protection from harm and passive and active rewarming methods 1.
- Moderate hypothermia (28-32°C): marked by decreased level of responsiveness, with or without shivering, and is considered a medical emergency requiring immediate attention and rewarming strategies 1.
- Severe hypothermia (below 28°C): characterized by unresponsiveness, minimal or absent shivering, and a high risk of cardiac arrest, necessitating aggressive rewarming techniques and medical intervention 1.
Importance of Early Recognition and Treatment
Recognizing the stages of hypothermia early is vital, as judgment becomes impaired during hypothermia, making self-rescue difficult. The progression of hypothermia can be rapid in cold water immersion or slower in cold air exposure, but all cases require immediate attention to prevent progression to more dangerous stages. Treatment should be tailored to the severity of hypothermia, ranging from passive rewarming with blankets for mild cases to active core rewarming techniques in medical settings for severe cases 1.
From the Research
Stages of Hypothermia
The stages of hypothermia are generally categorized into three levels: mild, moderate, and severe.
- Mild hypothermia is typically defined as a core body temperature between 32°C and 35°C 2, 3.
- Moderate hypothermia is defined as a core body temperature between 26°C and 32°C 3.
- Severe hypothermia is defined as a core body temperature below 26°C 3, 4.
Classification of Hypothermia
Hypothermia can be classified according to its origin as accidental or intentional, or by the degree of hypothermia as mild, moderate, or severe 5.
- Accidental hypothermia occurs when endogenous temperature control mechanisms are incapable of maintaining core body temperature within physiologic limits and core temperature becomes dependent on ambient temperature 4.
- Intentional hypothermia, also known as therapeutic hypothermia, is induced prior to cardiosurgical or neurosurgical procedures to reduce the risk of cerebral or cardiac ischemic damage 4, 5.
Treatment of Hypothermia
The treatment of hypothermia depends on the degree of hypothermia present and can range from noninvasive, passive external warming techniques to active external rewarming and active core rewarming 2, 6.