A Compensatory Reserve Index (CRI) device developed by Army medical researchers attaches to a soldier's finger and displays vital signs: body temperature, heart rate, breathing rate, and blood pressure. The matchbox-sized tool includes a computer display, wire, and plastic clip.
A chip-embedded "machine-learning algorithm" drives the technology's intelligence. The algorithm extracts the patient's vital signs using material waveform-based photoplethysmography — a non-invasive, optical method of detecting blood volume changes in the microvascular tissue.
If a patient is losing blood, the waveform changes and the algorithm analyzes the rate and type of change taking place. The software then predicts how long the patient has before he or she "decompensates" due to loss of blood and reaches a dangerous threshold. If the CRI indicates very poor vital signs, the medic would then know to provide blood or resuscitative fluids to the patient immediately.
In addition to the CRI, the medic has a smart tablet that shows vital signs of multiple casualties, all on one screen. Each Compensatory Reserve Index device transmits its data signal wirelessly to the smart tablet. For purposes of the Lab Day display, a Bluetooth was used for the transmission. In real-world operations, a more secure method of transmission would be needed.
Currently, CRI is being tested by the U.S. Food and Drug Administration for certification.
