Method and apparatus to assess compartment syndrome
Inventors
Ueno, Toshiaki • Hargens, Alan R. • Yost, William T.
Assignees
National Aeronautics and Space Administration NASA
Publication Number
US-7381186-B2
Publication Date
2008-06-03
Expiration Date
2024-08-02
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Abstract
A method and apparatus for measuring pressure buildup in a body compartment that encases muscular tissue. The method includes assessing the body compartment configuration and identifying the effect of pulsatile components on at least one compartment dimension. This process is used in preventing tissue necrosis, and in decisions of whether to perform surgery on the body compartment for prevention of Compartment Syndrome. An apparatus is used for measuring excess pressure in the body compartment having components for imparting ultrasonic waves such as a transducer, placing the transducer to impart the ultrasonic waves, capturing the reflected imparted ultrasonic waves, and converting them to electrical signals, a pulsed phase-locked loop device for assessing a body compartment configuration and producing an output signal, and means for mathematically manipulating the output signal to thereby categorize pressure build-up in the body compartment from the mathematical manipulations.
Core Innovation
The invention provides a method and apparatus for measuring pressure buildup in a body compartment that encases muscular tissue to detect Compartment Syndrome. The method includes assessing the body compartment configuration and identifying the effect of pulsatile components, such as blood flow, on at least one compartment dimension. An apparatus using ultrasonic waves along with a pulsed phase-locked loop device captures reflected ultrasound signals and mathematically manipulates these outputs to categorize pressure build-up within the compartment.
The invention addresses the problem of diagnosing Compartment Syndrome, where increased compartment pressure caused by bleeding or swelling impedes blood flow, potentially leading to tissue necrosis and permanent injury. Known invasive methods like needle pressure measurement are unreliable or uncomfortable, and non-invasive assessment methods are lacking. The present invention offers a non-invasive, reliable technique by measuring changes in compartment dimensions in response to pulsatile blood pressure changes, enabling early diagnosis and decision-making for surgical intervention or prevention of unnecessary incisions.
Claims Coverage
The claims include several independent claims that cover both processes and apparatuses for determining excess pressure in body compartments using ultrasonic techniques and pulsed phase-locked loop analysis. The main inventive features focus on non-invasive assessment of body compartment pressure by ultrasonic interrogation, capturing reflections, analyzing pulsatile components, and correlating dimensional changes to pulsatile blood pressure for diagnosis of Compartment Syndrome.
Process for determining presence or absence of excess pressure in body compartments
Utilizing a pulsed phase-locked loop device that transmits and captures temporal pulsed ultrasonic signals reflected off surface layers of the body compartment. The output signal is analyzed to determine dimensional changes and correlated with pulsatile blood pressure changes, where decreased dimensional changes indicate increased compartment pressure.
Apparatus for determining presence or absence of excess pressure in body compartments
Comprising transmitting and receiving devices (such as ultrasonic transducers) positioned adjacent to body compartments to impart and capture ultrasonic waves, means for assessing the compartment configuration via a pulsed phase-locked loop device, and means for analyzing and correlating dimensional changes in the compartment with pulsatile blood pressure changes to diagnose excess pressure conditions.
Use of mathematical and Fourier transform manipulations on output signals
Mathematically manipulating the pulsed phase-locked loop output signals, including Fourier Transform analysis, to identify a ratio of high-frequency to low-frequency amplitudes. This ratio permits categorization of intramuscular pressure and diagnosis of Compartment Syndrome by detecting changes in harmonic content of pulsatile responses.
Use of wave reflection from compartment boundary layers
Monitoring changes in reflection boundaries of the compartment, particularly the lower boundary, and creating an output signal in step with its movement in response to pulsatile blood pressure. Analyzing variations in output waveform shape referenced to blood pressure waves to ascertain pressure conditions.
The independent claims collectively define a non-invasive method and apparatus system that uses ultrasonic interrogation with a pulsed phase-locked loop to assess body compartment configurations, capture reflected signals, analyze pulsatile induced dimensional changes, and mathematically manipulate these signals to diagnose the presence or absence of excess pressure indicative of Compartment Syndrome.
Stated Advantages
Provides a non-invasive method for determining compartment pressure, reducing the need for invasive needle pressure measurements.
Enables early diagnosis of Compartment Syndrome by detecting changes in compartment dimension related to pulsatile blood pressure changes.
Prevents unnecessary surgical incisions by accurately determining absence of Compartment Syndrome.
Facilitates mathematical characterization and categorization of compartment pressure through Fourier and harmonic analysis of ultrasonic reflections.
Documented Applications
Diagnosis and evaluation of Compartment Syndrome in body compartments such as arms, legs, forearms, wrists, buttocks, thighs, and upper arms.
Medical decision-making to determine whether surgical intervention, like cutting the fascia, is necessary to relieve pressure build-up in compartments.
Non-invasive monitoring of intramuscular pressure for clinical and emergency triage scenarios.
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