What is the Triad of Death?
- It is the combination of hypothermia, coagulopathy, and acidosis leading to an increased mortality rate after experiencing traumatic hemorrhage. The body is sent into a spiral as each one of these events worsens.
- This vicious cycle can happen within minutes of injury, on-scene, en route to the hospital, and at the hospital. Hypothermia interventions should occur immediately and not be delayed until arrival at the hospital.
- Young, otherwise healthy adult patients may be able to compensate, and the harmful effects of the Triad of Death may not be as apparent during first patient contact. However, special consideration and attention must be given to other forms of traumatic bleeding, including geriatric patients (e.g., gastrointestinal bleeds), peripartum/postpartum bleeding, and pediatric patients. Active warming measures should be started as soon as possible, including warming the ice-cold blood products that are used.
- Early recognition and treatment of hypothermia is an equally important consideration that begins at the point of injury and should be implemented for all casualties, particularly patients at risk of experiencing shock.
What is Trauma-Induced Hypothermia (TIH)?
Trauma-Induced Hypothermia is caused by the sudden loss of circulating blood volume.
Hypothermia is considered a core body temperature of <36 degrees Celsius.
- Increase in mortality risk from hypothermia that begins at a temperature of 35.6°C
(<96°F). - Trauma patients requiring massive transfusion, hypothermia<36°C (96.8°F) on arrival was an independent predictor of mortality and associated with increased blood product consumption.”
(https://pubmed.ncbi.nlm.nih.gov/30444856/) - Hypothermia in trauma patients can deepen through environmental exposure on the scene or during transport and medical procedures such as infusions and airway management. Early prehospital recognition and prevention is the key to mitigating the negative effects.
(https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8391853/) - TIH can occur even in hot climates
(https://pubmed.ncbi.nlm.nih.gov/31859193/).
TIH By the Numbers (or “Why Blood Must Be Warmed”):
TIH Is Common:
Hypothermia is common in trauma patients, with approximately 40% to 50% of moderate to severely injured patients arriving in a hypothermic state at civilian hospitals and >80% of non-surviving patients arriving with a core temperature <34°C (93°F).
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7454138/, https://pubmed.ncbi.nlm.nih.gov/3656464/
TIH Complicates Resuscitation Efforts
With as little as 500mL of cold blood, a patient’s core temperature will drop by about 1°C, and coagulation factor activity will drop by approximately 10%–15% for each 1°C drop in temperature.
(https://jts.health.mil/assets/docs/cpgs/Hypothermia_Prevention_Treatment_07_Jun_2023_ID23.pdf)
Since the patient may already be hypothermic prior to initiating the blood transfusion, the adverse impact of cold blood is likely to be accelerated. As a result, it is not surprising that:
- TIH mortality rates can be twice that of normothermic casualties with similar injuries.(https://jts.health.mil/assets/docs/cpgs/Hypothermia_Prevention_Treatment_07_Jun_2023_ID23.pdf)
- TIH is also associated with increased transfusion requirement, mortality, and ICU admission.(https://www.sciencedirect.com/science/article/pii/S0020138323006599)
Identified predictors for hypothermia included the severity of the injury, intubation, and immobilization, as well as winter season, SBP < 90 mmHg, and GCS ≤ 8.
(https://www.sciencedirect.com/science/article/pii/S0020138323006599)
Hypothermia isn’t just for trauma patients:
Other patient groups will benefit from warming blood products or IV fluids.
- Burn patients are at extreme risk for hypothermia. In the prehospital setting, passive and active warming measures, including warming IV fluids, should be taken.
(https://pubmed.ncbi.nlm.nih.gov/31378620/). - Hypothermia is common in patients who have overdosed on certain medications, including sedative-hypnotics, opioids, and ethanol. These substances can impair thermoregulation and make it harder for the body to respond to cold temperatures. Hypothermia can also occur when environmental exposure is combined with an opioid overdose.
(https://www.brown.edu/news/2019-06-17/cold-overdoses, https://www.uptodate.com/contents/accidental-
hypothermia-in-adults/print.)
How Can We Manage Hypothermia in the Prehospital Setting?
Active warming of patients to prevent TIH is currently the only viable method available to improve patient outcomes. (https://emj.bmj.com/content/30/12/989)
The Joint Trauma System, the agency responsible for providing clinical guidance to the deployed military healthcare system, strongly advocates for aggressive and preventative measures to combat hypothermia. It has dedicated an entire Clinical Practice Guideline to the topic (JTC CPG Hypothermia: Prevention and Treatment) (https://jts.health.mil/assets/docs/cpgs/Hypothermia_Prevention_Treatment_07_Jun_2023_ID23.pdf).
Credit: Dr. Randall M. Schaefer (Lieutenant Colonel, US Army, Retired), DNP, RN, ACNS-BC, CEN
