Collaboration with WPI could save wounded soldiers

Early detection of blood loss the goal of three-year program funded by U.S. Army

By Michael Cohen

UMass Medical School Communications

August 23, 2012
sensor-soldiers

Early detection of blood loss to save the lives of soldiers wounded on the battlefield is the goal of a three-year research and development project to be launched this fall at Worcester Polytechnic Institute in collaboration with UMass Medical School and UMass Memorial Medical Center. The research will be funded by a $1.9 million grant from the U.S. Army.
 
The project will be led by Ki Chon, PhD, professor and head of WPI’s Biomedical Engineering Department, and Yitzhak Mendelson, PhD, associate professor of biomedical engineering at WPI. Members of the WPI team will develop miniaturized wireless sensors that soldiers can wear into battle. They will also create the mathematical algorithms needed to process signals from those sensors to simultaneously measure seven physiological parameters, including a novel way to detect bleeding. In addition to sensors worn on the body, the WPI team will place the same monitoring capabilities on smartphones, which Army medics can use as hand-held diagnostic tools.

Both the wearable sensor and smartphone technologies will be evaluated by UMass Medical School faculty clinicians in an observational study of trauma patients directed by Chad Darling, MD, assistant professor of emergency medicine, and David McManus, MD, assistant professor of medicine.

The monitoring system to be developed will use light to measure vital signs. Small sensors will shine infrared and visible light through the skin and detect how different frequencies of light are absorbed by pulsing arterial blood. A series of algorithms will correlate subtle shifts in the spectra to a wide range of physiological parameters. On the smartphone platform, the built-in video camera will provide the light and record the reflections. It is the same basic technology used in pulse oximeters, those now-familiar devices that clip on a patient’s finger to measure blood oxygen levels. Dr. Chon and Dr. Mendelson’s approach, however, takes the technology to a far more sophisticated level.

Beginning in the second year of the project, prototypes developed at WPI will be used by the UMass Memorial Medical Center’s emergency department to monitor trauma patients’ vital signs and detect blood loss. Severely injured patients, usually accident victims, will be monitored as they are transported by the medical center’s Life-Flight helicopter. Other patients will be monitored when they arrive in the emergency room by ambulance, using both wearable sensors and the smartphone application. In addition, the UMMS clinical team will help develop decision support tools to be embedded in the smartphone. When the monitoring system is deployed in the field, those tools will respond as vital signs are measured and prompt a medic or first-responder with information to guide treatment.

“This is a very exciting program, and we’re pleased to be able to work with the WPI team,” said Dr. Darling. “The majority of trauma victims we see have a blunt-force injury, with no visible signs of bleeding. So we are always concerned about internal bleeding, and typically order a CT scan to see

what’s happening inside. An early-detection system for internal bleeding would be helpful, and certainly would be very important for first-responders in the field.”

Dr. McManus said that the clinical research team has designed an ambitious study that will monitor trauma patients in the field, and follow them through the emergency department and on to surgery or intensive care as their treatment dictates. The new WPI systems will not be used to make medical decisions during this phase of development. As qualifying trauma patients undergo diagnosis and treatment, research coordinators will use the prototypes to monitor patients and capture data. The corresponding sensor data will then be analyzed and correlated with the clinical data the trauma team recorded and used to determine the actual extent of blood loss.

“Having the opportunity to collaborate with the trauma team at UMass Medical is extremely important for our work,” Mendelson said. “Their clinical understanding and experience will help us refine the technology.”