Non-invasive Intracranial Pressure Measurement

health medicine and biotechnology
Non-invasive Intracranial Pressure Measurement (LAR-TOPS-248)
Constant frequency pulsed phase-locked loop technology as the means for measuring transcranial expansion
Overview
An acknowledged objective of critical care medicine is a timely, accurate, readily deployable, cost-effective and, importantly, safe means of assessing and/or monitoring critical aspects/parameters of patient condition such as intracranial pressure. However, ICP monitoring is complicated by a large set of variables related to the patients themselves -- presented symptoms, circumstances, and related information indicating such measurement; and relevant accompanying issues. These conditions and the various combinations thereof present attending physicians with the choice of many alternatives regarding key parameters, including but not limited to urgency, availability, appropriability, and accuracy to a minimum standard. Cost, complexity, ease of use and other issues are also meaningful factors, but the bottom line for any of the various technical approaches, whether invasive or non-invasive, is performance. Key to this technology is its capability to correlate closely with established tympanic membrane displacement (TMD) ICP monitoring technology.

The Technology
This technology and a product based on it offer new analytical capabilities for assessment of intracranial dynamics. It offers the possibility for the monitoring of transcranial expansion and related physiological phenomena in humans resulting from variations in intracranial pressure (ICP) caused by injuries to the head and/or brain pathologies. The technology uses constant frequency pulse phase-locked loop (CFPPLL) technology to measure skull expansion caused by pressure and its variations in time. This approach yields a more accurate, more robust measurement capability with improved bandwidth that allows new analytical approaches for assessing the physiology of skull expansion under pulsatile cerebral blood flow. The dynamical quantities assessable with the CFPPLL include skull volume expansion and total fluid. Such an instrument can serve to measure intracranial dynamics with equation based algorithms, and offers a path to measure or determine quasistatic intracranial pressure, along with the pulsatile related intracranial pressure increments. Supportive measurements, such as time dependence of arterial pressure waveforms together with time dependent phase change of transcranial expansions can serve as the basis of noninvasive techniques to measure intracranial pressure.
Diagram showing the mounting of the transducer. Functional block diagram of the Constant Frequency Pulsed Phaselocked Loop. Image credit: NASA
Benefits
  • Based on known and well understood principles, yielding data that demonstrate close correlation with a known non-invasive ICP monitoring technology, tympanic membrane displacement
  • Implementation of the technology would be straightforward and of low impact to the patient in a clinical setting

Applications
  • Application of the technology to limited and narrowly defined settings, such as on board emergency vehicles responding to medical emergencies and other medical triage situations outside of medical facilities, may present opportunities such as specific application subsets of ICP monitoring, as in remote, non-medical facilities and in emergency/triage facilities and/or equipment (e.g., battlefield settings, ambulances/EMS vehicles, etc.) in which the products likely low cost, small footprint and ease of use may constitute compelling advantages
  • Further refinement of the technology to yield ICP monitoring data more closely matching those of invasive procedures may be possible
Technology Details

health medicine and biotechnology
LAR-TOPS-248
LAR-18581-1 LAR-18581-2
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