Early detection of blood loss to save the lives of soldiers wounded on the battlefield and to help civilian trauma victims is the goal for a three year R&D project just launched at the Worcester Polytechnic Institute (WPI). Funded by an Army grant, the research will be conducted in collaboration with the University of Massachusetts Medical School (UMMS) in their Biomedical Engineering Department.
The team will work on two projects. Ki Chon, PhD, Professor and Head of WPI’s Biomedical Engineering Department and Yitzhak Mendelson, PhD, Associate Professor of Biomedical Engineering are going to develop miniaturized wireless sensors that soldiers can wear.
At the same time, 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 smart phones so that Army medics will be able to have the use of hand-held diagnostic tools. Both the wearable sensor and smart phone technologies will be evaluated at the medical school in an observational study of trauma patients to be directed by Chad Darling, M.D. Assistant Professor of Emergency Medicine, and David McManus, M.D., Assistant Professor of Medicine.
To do the research, Chon’s lab will focus on signal processing and adapting the technology for use on a smart phone, while Mendelson’s team will lead the wearable sensor device development.
The monitoring system under development 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 smart phone platform, the built-in video camera will provide the light and record the reflections.
This 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. Chon and Mendelson’s approach takes the technology to a far more sophisticated level.
The WPI team will continue hardware, software, and algorithm development to optimize the sensors’ size, durability, and accuracy. They will also evaluate where best to place sensors on the body simultaneously. The sensors will also include embedded accelerometers to measure body movement and posture, along with a wireless link to allow a medic to monitor the health of soldiers.
According to Mendelson, one of the biggest challenges of sensor development for battlefield conditions is maintaining accurate measurements while soldiers are moving. Motion artifact contamination, which is interference caused by body movements, degrades the quality of the signals being measured and can lead to erroneous readings.
Beginning in the second project year, prototypes developed at WPI will be used by the UMass Memorial Medical Center’s emergency department to monitor trauma patients’ vital signs to detect blood loss. Severely injured patients 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 center’s emergency room by ambulance, using both wearable sensors and the smart phone application. In addition, the U Mass Medical Center’s clinical team will develop decision support tools to be embedded in the smart phone.