FORT DETRICK, Md. – Uncontrolled blood loss from traumatic injury is the leading cause of preventable death on the battlefield, which makes prompt and accurate triage essential for maximizing Warfighter survival. However, the body’s own defense mechanisms can make it difficult to identify someone at greatest risk for the early onset of shock. A new technology that builds on pioneering research conducted at the U.S. Army Institute of Surgical Research may soon enable care givers to assess patient risk more quickly and accurately using data collected from ordinary digital cameras, thereby improving the survivability of combat casualties and increasing the combat power and effectiveness of field units.
Traditionally, medical professionals assess a patient’s status by relying on the patient’s vital signs – blood pressure, heart rate, and oxygen saturation. However, when subject to traumatic blood loss, the human body automatically engages a survival mechanism – called the compensatory reserve – that concentrates the remaining blood near the heart, brain, and other vital organs. This results in these standard vital signs to remain relatively normal for a time until the body can no longer compensate for the blood loss, triggering what doctors call a “crash” that is often fatal.
“It’s analogous to driving your car and being unsure of how much gas you had left because the gas gage doesn't change until the very end, just as you are about to run out of gas,” explains Dr. Victor Convertino, USAISR’s senior scientist for combat casualty care and director of the Battlefield Health and Trauma Center for Human Integrative Physiology. “You may be able to drive for 300 miles, or you may only have three miles left. That’s the challenge we’re faced with.”
Convertino’s groundbreaking research into the body’s inherent physiologic compensatory mechanisms led to the development of the compensatory reserve measurement, or CRM, a machine-learning algorithm that provides a more reliable prediction of hemorrhagic shock risk than traditional vital signs.
In addition to providing medical care providers with a more accurate assessment tool for hemorrhagic shock, the CRM is the first monitoring technology that can assess the blood volume status of an individual patient regardless of the patient’s individual tolerance for blood loss, which determines how quickly they will crash from an ongoing loss of blood. This has long been a mystery for clinicians; Convertino calls it a “curveball” that can catch even the most attentive doctors and nurses off guard.
To put this new diagnostic capability into the hands of medical professionals and Warfighters, Convertino, Dr. Jose Salinas, and Dr. Eric Snider of USAISR’s Automation and Engineering Group – one of five research groups within USAISR focusing on using state-of-the-art technologies such as advanced artificial intelligence to address critical medical gaps – have teamed up with health software firm Presage Technologies to incorporate the CRM algorithm into a new software application that could transform battlefield triage of trauma-induced hemorrhage.
The software builds on work that Presage has done with several DOD clients to demonstrate that commercial grade video cameras – such as those used in drones, webcams, and smart phones – are capable of capturing microscopic movement and color changes in a person’s skin caused by their pulse. The software converts those changes into a waveform that can be compared against the CRM algorithm to predict the patient’s risk of slipping into shock. Presage has developed the software to the point where it is ready for submission to the U.S. Food and Drug Administration seeking its clearance to legally market the software for use in novel military and civilian medical applications.
With such a capability readily available, medics operating in a combat environment could use drones to observe injured Warfighters without risking injury to themselves, for example. Nurses responding to a mass casualty incident could use their phones to perform triage using just a few seconds of video footage for each patient. Physicians would be able to continuously monitor patients postoperatively for signs of internal bleeding, shock, and sepsis. Such cutting-edge, deployable trauma care solutions promise to materially improve Warfighter survivability and lethality.
As part of this effort, the Metis Foundation, a San Antonio-based nonprofit that supports military medical research, is providing extramural assistance for the project using funding provided by the Medical Technology Enterprise Consortium, a nonprofit international group of over 600 academic institutions, businesses, nonprofits and other organizations in the biomedical technology sector. Convertino says that the foundation’s participation has been crucial for ensuring the success of the project.
Convertino hopes that the collaboration with Presage to develop diagnostic capabilities for digital cameras will be the first of many innovative applications of the CRM, which he and his colleagues have spent years researching and refining.
“The beauty of the CRM algorithm is that it was purposely built to be hardware agnostic,” says Convertino. “We can team with almost any industry partner who has a monitoring capability, integrate the algorithm into it, and then they can bring their device to the FDA as a software upgrade that doesn’t require a lengthy approval process as a new medical device. That will help speed our ultimate goal, which is to get this capability into the hands of medics, whether they're military or civilian, so it can help them save lives with earlier lifesaving interventions.”
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