You and your partner give thanks for your new ambulance that has a separate gasoline generator to run the air conditioning system, which you have set at 65ºF in the patient compartment.
Your patient, a 72-year-old woman, fell in her kitchen last night and lay there all night, unable to move because of an obvious right hip fracture. A neighbor checked on her around noon, found her and called 9-1-1. On arrival you find the patient confused and unable to give many details of her fall except that it was “yesterday.” She has been incontinent of urine and feces and moans in pain as you examine her. You decide to give her 100 mcg of fentanyl before moving her, so you start a line with normal saline and, because her blood pressure is 82/50, decide to administer 500 mL of fluid. Your IV bag is cold, having been in the patient compartment all morning with the air conditioning running.
After the woman’s pain abates, you place her on a scoop stretcher and then on your ambulance stretcher. As you struggle to make your way down the steep stairs from her front porch to the sloping sidewalk, sweat pours off both you and your partner, and you silently curse both dispatch for not sending fire to help and yourselves for not calling for additional assistance. But once in the back of the ambulance, the cool air feels refreshing, and you set off for the Level III hospital 30 minutes away. Because the patient’s BP has not responded well to the initial bolus, you quickly run in another 500 mL of fluid and then cut back to a rate of 1,000 mL/hour. You hand her over to the ED staff without further incident.
Two weeks later one of the ED nurses says, “Remember that patient you brought in a couple of weeks ago with the fractured hip? That was my great-aunt, and she just died in the ICU. She got DIC and ARDS, and they couldn’t save her.”
“DIC and ARDS?” you say. “How did that happen?”
The Triad of Death
The link between poor survival in trauma patients and the so-called triad of death—coagulopathy, hypothermia and metabolic acidosis—is well known.1 Once it occurs, hemorrhage control and prevention of acidosis are difficult. If a patient arrives in an emergency department in this condition, their odds of survival are diminished.2
Much has been written about the so-called Golden Hour in trauma, yet there is scant, if any, evidence supporting the notion that prehospital times affect survival.3 Conversely, while there is much evidence that hypothermia leads to complications relating to poor survival—literally dozens of studies have traced its role in the other two aspects of the triad, acidosis and coagulopathy—little has been written about the role of prehospital care in the prevention of the triad of death. In this article we will examine the role of hypothermia in the development of the triad and its sequelae, disseminated intravascular coagulation (DIC), acute respiratory distress syndrome (ARDS) and acidosis.
We know hypothermia increases fluid requirements and independently increases acute mortality after major injury.4 Moreover, it can be a consequence of severe exsanguinating injury, and subsequent fluid administration during resuscitation efforts can lead to tissue hypoperfusion, diminished oxygen delivery, reduced heat generation, cardiac dysrhythmias, decreased cardiac output, increased systemic vascular resistance, and a leftward shift of the oxygen-hemoglobin dissociation curve.4