In the trenchesDARPA looking for methods to freeze soldiers with brain injuries

Published 13 November 2009

Traumatic brain injuries are caused by repeated exposure to blasts, specifically the “supersonic wave” of highly-pressurized air they emit; within a fraction of a second after impact, brain cells, tissues, and blood vessels are stretched, torn, and distorted; over the hours, days, and months that follow, altered brain processes create a snowball effect of damage — which is why symptoms often don’t show up until troops come home; in its solicitation, DARPA notes that a portable brain-cooling unit, deployed in the field, could “extend the golden hour of patient survivability and increase the chances for full recovery”

Since 2007, more than 70,000 U.S. troops have been diagnosed with traumatic brain injury. DARPA offers a new way of dealing with the problem: freeze ‘em.

Katie Drummond writes that DARPA, the U.S. military’s push-the-envelop research arm, is looking for research projects that would create a “therapeutic hypothermia device” to prevent traumatic brain injuries from causing permanent molecular damage to the brain. The idea is based on successful studies that used cortical cooling to treat survivors of strokes and cardiac arrest. According to DARPA’s solicitation, cooling down the brain after trauma can offer “dramatic neuroprotection” that will prevent long-term harm to cognition and motor skills.

So far, DARPA-funded studies suggest that traumatic brain injuries are caused by repeated exposure to blasts, specifically the “supersonic wave” of highly-pressurized air they emit. Within a fraction of a second after impact, brain cells, tissues, and blood vessels are stretched, torn, and distorted. Over the hours, days, and months that follow, altered brain processes create a snowball effect of damage — which is why symptoms often do not show up until troops come home.

Drummond writes that these secondary changes to the brain are responsible for the long-term physical and cognitive symptoms endured by TBI sufferers, and they are what DARPA wants to curb. Once the processes set in, around 90 minutes after impact, they are hard to reverse. This is why a quick dose of hypothermia might come in handy: a portable brain-cooling unit, deployed in the field, could “extend the golden hour of patient survivability and increase the chances for full recovery.”

That is, if researchers can get the thermostat right. The right degree of cortical cooling has proven effective, but cortical hyperthermia can actually worsen cortical trauma. No two brains are the same: DARPA’s solicitation notes that the ideal cooling temperature will “differ across individuals and injury.”

DARPA is asking for a prototype, complete with internal “temperature calibration technology” to optimize cooling temp and avoid “rewarming [the brain] too quickly.” A portable brain freezer will be a boost for civilians too: Americans are about as likely to suffer a TBI as heart disease.