SBIR-STTR Award

Nascent will adapt recent work at the Mayo Clinic in vibro-acoustics to make a non-invasive, portable sensor for the diagnosis of compartment syndrome-a condition in which high pressure within a closed fascial space (muscle compartment) reduces capillary blood perfusion below the level necessary for tissue viability. Vibro-acoustics is a form of elasticity imaging in which a focused ultrasound beam is used to apply a localized pressure field to a tissue. This pressure produces an acoustic response proportional to the size, shape and viscoelastic properties of the tissue. In a recent laboratory test, this acoustic response was highly correlated with the internal pressure of a latex tube filled with water. In the Phase 1, Nascent proposes a series of phantom studies to test the ability of vibro-acoustics to measure intramuscular pressure. In addition, Nascent will design and test low-cost, portable instrumentation suitable for field studies of the vibro-acoustic sensor. A series of human cadaver tests will be conducted to provide final validation of this instrumentation for compartment syndrome diagnosis. This sensor will provide a portable, non-invasive method for diagnosing compartment syndrome for both military and civilian uses. A portable, low-cost vibro-acoustic sensor may also have other uses in medical diagnostics and nondestructive evaluation of materials

Nascent will develop a noninvasive, portable and low-cost ultrasonic sensor that can accurately diagnose compartment syndrome in battlefield conditions. The sensor employs an ultrasonic pulsed phase locked loop (P2L2) to measure sub-micrometer changes in muscle compartment width. In Phase I, these changes were shown to correlate with changes in intramuscular pressure (IMP). More significantly, Nascent determined that the P2L2 is sensitive enough to detect arterial pulses in the muscle compartment. This sensitivity makes possible more sophisticated diagnostics for compartment syndrome than is now possible with direct measurement of IMP using invasive, catheter-based measurements. In Phase II, Nascent proposes to convert its existing, laboratory-based P2L2 into a portable instrument suitable for use in battlefield care, hospitals, trauma centers, and disaster sites. This instrument will be tested on human subjects at University of California, San Diego School of Medicine. Additional tests will be conducted at the College of William and Mary’s Department of Kinesiology in Williamsburg, Virginia, while Nascent will receive consulting assistance in medical ultrasound technology from the Mayo Clinic in Rochester, Minnesota.

Benefits:
This sensor will provide a portable, noninvasive method for diagnosing compartment syndrome for both military and civilian uses. The technology could also lead to a new class of low-cost, portable physiology monitoring tools based on ultrasonic characterization of the mechanical properties of tissue.

Keywords:
Compartment Syndrome, Intramuscular Pressure, Ultrasound, Pulsed Phase Locked Loop, Tissue Characterization, Noninvasive Physiology Monitoring