Tiny Triage Device Could Save Lives on the Battlefield

Reprinted from www.army.mil.

WASHINGTON (Army News Service, May 15, 2015) -- Getting rapid treatment for wounds or injuries suffered on the battlefield can mean the difference between life and death.

Army medical researchers recently developed "a device that will revolutionize triage," said Lt. Col. Robert Carter. In other words, it could lower casualties in the first few minutes dramatically.

Carter, task area manager for Tactical Combat Casualty Care Research at the U.S. Army Institute of Surgical Research, Joint Base San Antonio, Texas, spoke during Lab Day at the Pentagon, May 14.

He demonstrated the Compensatory Reserve Index, or CRI, device. It's about the size of a small matchbox with a computer display. A wire connects it to a plastic clip that's placed on an injured soldier's finger.

Once it's attached to a soldier's finger, it displays vital signs: body temperature, heart rate, breathing rate and blood pressure. 

"One of the challenges now with triage is that with multiple casualties on the battlefield, the medic may have a difficult time determining which patients need to be treated first," Carter said.

He explained that while someone who is bleeding profusely might obviously need to receive care first, someone else may be suffering from internal injuries caused by a blast that resulted in injuries even more severe. But the extent of those injuries would likely go unnoticed until the vital signs were taken.

With the CRI, the medic can quickly snap the device on to everyone who is down and the vital signs are almost immediately displayed, Carter said. 

In addition to the CRI, the medic has a smart tablet that displays multiple vital signs of multiple casualties, all on one screen, he said. So once the medic snaps the CRI on a finger, he doesn't need to monitor each one. He can see the data from all patients on one screen and that makes it easier to keep track of things and do the prioritization.

Each CRI transmits its data signal wirelessly to the smart tablet. For purposes of the Lab Day display, a Bluetooth was used for the transmission, but Carter said in real-world operations, a more secure method of transmission would be needed. That determination has not yet been made.

The most important aspect of CRI is the "machine-learning algorithm" embedded in its chip that drives its intelligence, Carter said.

That algorithm extracts the patient's vital signs using "a material waveform-based photoplethysmography," which is the medical way of saying that it uses a non-invasive, optical method of detecting blood volume changes in the microvascular tissue, he said.

So, for example, each time the heart contracts, blood enters the finger at a maximum rate and as the heart muscle relaxes, the amount of blood decreases. The algorithm analyzes the wave form it produces over time, meaning a matter of seconds, he said.

If a patient is losing blood, the waveform changes and the algorithm analyzes the rate and type of change taking place. It predicts how long the patient has before he "decompensates" due to loss of blood and reaches a dangerous threshold where death is at risk.

If the CRI indicates very poor vital signs, the medic would then know to provide blood or resuscitative fluids to the patient immediately, Carter said, before it's too late to resuscitate him.

Another appealing factor of the CRI is that it's inexpensive and rugged, Carter said. During the interview, he inadvertently dropped the CRI and it continued to work.

Currently, CRI is being tested by the U.S. Food and Drug Administration for certification. Then the Army will determine whether or not to field it, Carter said. Meanwhile, multiple civilian trauma care centers and clinics around the country are testing and using the device, as the Army has decided to share its technology.

"Right now, the Israeli Defense Force is using it and saving lives," he added, predicting that in the future, CRI "will save a lot of time and a lot of lives" when it gets in the hands of U.S. Army medics.