Hypothermia

HYPOTHERMIA

Hypothermia, defined as a temperature ≤35° Celsius, is common in critically ill trauma patients and is one of the most important physiological predictors for early and late mortality in trauma patients. It is aggravated by traumatic hemorrhage, which leads to hypovolemic shock. Hypovolemic shock drives a lethal triad of hypothermia, coagulopathy, and acidosis, leading to worsening hemorrhage. 

Hypothermia in trauma patients leads to higher in-hospital mortality, higher transfusion requirements, and a longer length of stay. Mortality increases with the degree of hypothermia in severely injured patients.  A recent systematic review included seven studies for meta-analysis and concluded that accidental hypothermia at admission was associated with significantly higher mortality in trauma patients with an OR of 5.18 (95% confidence interval (CI), 2.61–10.28).

Non-trauma-related mild hypothermia, defined as a body core temperature between 32 degrees Celsius and 35 degrees Celsius, is generally well tolerated. Researchers found a 21% mortality rate in patients with a core temperature of less than 32° C, originating from environmental exposure. However, that same degree of hypothermia following traumatic injury resulted in 100% mortality, independent of the presence of shock, injury severity score, or fluid resuscitation. 


The effects of hypothermia can cause or contribute to serious conditions such as:


The warming of IV fluids and blood products,  using devices such as the Belmont buddy lite and the Belmont Rapid Infuser, represents one of the many ways that we may combat hypothermia and the numerous negative effects that it has in the setting of trauma.  Cold fluid resuscitation can substantially decrease core temperature. The warming of IV fluids and blood products, therefore, not only counteracts existing hypothermia but, perhaps even more importantly, prevents the thermal stress and thermodilution that occurs when ambient temperature fluids are infused, 

The Swiss staging system for hypothermia is presented below, along with clinical physiology and recommended interventions.