Measuring Intra/Extracellular Volume and Hemodynamics

DESCRIPTION (provided by applicant): LDM Associates (LDM) proposes to complete the development of their combined impedance plethysmographic (IPG) and electrical impedance spectroscopic (EIS) instrumentation that will allow noninvasive real-time relative measurement of segmental blood flow, intracellular, interstitial, and intravascular volumes. This instrument will be the first of its kind that can measure both blood flows and segmental compartment volumes. It will also be the only instrument that can be used to measure interstitial fluid volumes in addition to intra/extracellular volumes. In Phase I, LDM completed the design and fabrication of four prototype units and conducted a series of preliminary tests that demonstrated the feasibility of our proposed system and provided valuable information that was needed to refine the computer control data acquisition and analysis software that is an integral part of our instrumentation. In Phase II, LDM will further develop and optimize an IPG/EIS system to include a multi-segment interface, a bedside monitoring configuration, and advanced control/display software. In Phase II, a series animal and human studies will be performed to validate the instrumentation using "gold standard" compartment volume monitoring techniques. Additional human studies will be performed at New York Medical College and George Washington University to verify and demonstrate the use of the instrumentation to monitor segmental volume changes of end stage renal disease patients during dialysis. LDM will also finalize current preliminary arrangements for the intellectual protection, manufacture, marketing, and customer support of our instrumentation. This inexpensive, easy to use device will provide vital information in the treatment of diverse pathophysiologic fluid volume and hemodynamic states including, for example, the management of increased intracranial pressure following trauma, the treatment of disequilibrium and hypotension during renal dialysis, the monitoring of hydration state of premature infants, and the investigation and diagnosis of orthostatic intolerance associated with dysautonomia and space flight.