N21A-T013 TITLE: Real-time Monitoring for Decompression Sickness
RT&L FOCUS AREA(S): Biotechnology
TECHNOLOGY AREA(S): Biomedical; Human Systems; Sensors
OBJECTIVE: Real-time biomonitoring capabilities that predict risk of Decompression Sickness (DCS) onset have the potential to improve safety for military divers and at the same time expand operational capabilities.
DESCRIPTION: DCS is a leading risk and time-limiting factor for diving operations. Avoiding DCS requires ascending in accord with often lengthy decompression schedules that are designed for the majority of divers and the most arduous diving conditions. Currently, there is no technology to tailor decompression schedules to the physiological state of individual divers. DCS is assumed to result from the formation of bubbles in tissues and blood, and there is an association between bubbles detected in the blood (VGE) post-dive and the occurrence of DCS. Detection of VGE in real time during diving may improve prediction of DCS and potentially could be used for real-time control of decompression. Development of technology for monitoring VGE during diving could enable optimization of decompression to the diver’s physiological state.
PHASE I: Demonstrate feasibility through analysis and limited laboratory demonstrations, a noninvasive sensor device that is capable of measuring blood and tissue bubbles and is to be worn by pool swimmers/divers, surface supplied divers, and free swimming divers underwater. Note: Ideal features for the final product would be non-invasive, of similar size and weight to a diver worn dive computer, records bubble events along with dive time and dive depth for later analysis, and has sufficient autonomous power and data storage to record bubble events for at least 20 hours of diving. Provide cost of system, cost per dive, and reliability estimates, including lifetime expectancy and lifetime cost estimate. The required Phase I deliverables (in addition to those outlined in the DON 21.A Proposal Submission Instructions) will include: 1) a research plan for engineering the design of the waterproof device with embedded sensors; 2) a preliminary prototype, either physical or virtual, capable of demonstrating effectiveness (accurately and reliably predict and capture changes in bubbles as measured against those established in the scientific literature) of the proof-of-concept of design; and 3) a test and evaluation plan to validate accuracy of data collection including identification of proper controls. Consider projections regarding the latency of data collection. Device should target bubbles in micron scales as is possible with capacitive micromachined ultrasound transducer (CMUT) technology, and capable of capturing bubble formation and presence in both blood and tissue. Provide key information about the uses and limitations of the system and could include rapid prototyping and/or modeling and simulation. Develop a Phase II plan.
PHASE II: Develop, demonstrate and validate an underwater ultrasound sensor prototype. Ensure that the system can be used submerged in water temperatures from 32 °F to 90 °F to collect and analyze data and test detection algorithms during diving activity. Design the initial prototype for use in a dive computer or as an independent wearable device compatible with and not to interfere with traditional dive gear; and may be intended for experimental or training use and need not be adapted for operational use. It is expected that the algorithm development for real-time closed-loop feedback capabilities will require data collection first so this will be an iterative staged product development.
PHASE III DUAL USE APPLICATIONS: Transition prototype to a functional unit to the U.S. Navy’s Naval Sea Systems Command Supervisor of Salvage and Diving (NAVSEA SUPSALV), Naval Special Warfare (NSW), and/or Naval Air Systems Command (NAVAIR) Aircrew Systems Program Office (PMA-202). Operationally relevant conditions may necessitate additional parameters such as greater depths, prolonged data collection, and eliminating motion artifacts. Technology could be commercially developed as a civilian dive computer.
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KEYWORDS: Decompression Sickness; DCS; Bubbles; Venous Gas Emboli; Ultrasound; Waterproof; Physiological Monitoring; Hyperbaric Gas Physiology