Systems and methods for sensing lung fluid and functionality
Inventors
Elia, Liron • Iddan, Gavriel J.
Assignees
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Publication Number
US-11678843-B2
Publication Date
2023-06-20
Expiration Date
Abstract
An apparatus for monitoring for accumulation of lung fluid comprises a feeding tube having first electrode(s) positioned thereon for electrical contact with tissue of an esophagus of a target patient including a lower esophageal sphincter (LES) and/or tissue in proximity to the LES, second electrode(s) sized and shaped for contacting skin of the target patient, and a non-transitory memory having stored thereon code instructions for applying alternating current(s) to pair(s) of first and second electrodes, measuring a voltage over the pair(s), and computing an estimate of a change of lung fluid relative to a baseline in lung(s) of the target patient according to the applied alternating current and measured voltage, wherein the applying, the measuring, and the computing the estimate of the change in lung fluid are iteratively executed for monitoring the target patient for accumulation of lung fluid while the feeding tube is in use.
Core Innovation
The invention provides an apparatus for differentiating between medical states of a subject using an impedance sensor formed by a feeding tube with at least one first electrode disposed on a distal end located in the esophagus and at least one second electrode sized and shaped for contacting a surface of the skin. The selected electrode pair denotes a respective selected impedance sensor positioned for sandwiching a lung and for avoiding passing current through the heart.
While the feeding tube is in use, the apparatus selects a combination including a selected frequency spectrum of an alternating current and a selected electrode pair. The apparatus computes an impedance value according to voltage over the respective selected impedance sensor and according to the alternating current applied at the selected frequency spectrum, and then computes a sub-impedance score according to the computed impedance value.
The apparatus iterates by selecting combinations that include an electrode pair not previously selected and applying at least another selected frequency to obtain a plurality of computed sub-impedance scores. The document emphasizes real-time monitoring of lung fluid change by repeatedly computing impedance and sub-impedance scores and differentiating medically significant states such as pleural effusion and pulmonary edema, while avoiding passing current through the heart.
Claims Coverage
The document includes three independent claims covering an apparatus, a method, and a computer program product for differentiating between at least two medical states using selected AC frequency spectra, impedance sensors formed by feeding-tube and skin electrodes, iterative computation of sub-impedance scores, and differentiation based on the plurality of sub-impedance scores.
Electrode pair impedance sensor from distal esophageal feeding tube and skin contacting electrode
The apparatus includes a feeding tube with at least one first electrode disposed on a distal end located in the esophagus and at least one second electrode sized and shaped for contacting a surface of the skin, where the selected electrode pair denotes a respective selected impedance sensor positioned for sandwiching a lung and for avoiding passing current through the heart.
Frequency-spectrum selection of alternating current for impedance measurement
The apparatus selects a combination including a selected frequency spectrum of an alternating current and a selected electrode pair, and applies the alternating current at the selected frequency spectrum to obtain impedance values via the respective impedance sensor.
Iterative computation of impedance value and sub-impedance score across new electrode pairs and selected frequencies
The apparatus computes an impedance value according to voltage over the respective selected impedance sensor and according to the alternating current applied at the selected frequency spectrum, computes a sub-impedance score according to the computed impedance value, and iterates such that for each iteration another combination is selected that includes an electrode pair not previously selected in previous iterations and at least another selected frequency.
Differentiating between medical states using a plurality of computed sub-impedance scores
The apparatus differentiates between at least two medical states of the subject according to the plurality of computed sub-impedance scores.
Iterative selection of different electrode pairs and alternating current frequencies for impedance and sub-impedance scores
The method iterates for a plurality of iterations, wherein for each iteration another combination is selected including at least another selected frequency of an alternating current applied by a respective selected electrode pair denoting an impedance sensor positioned for sandwiching a lung and for avoiding passing current through the heart, and a different electrode pair is selected for a current iteration that has not been selected in previous iterations.
Computing impedance values and sub-impedance scores at selected frequencies
The method computes a plurality of impedance values according to voltage over the respective selected impedance sensor and according to each respective alternating current applied at the respective selected frequency, and computes a plurality of a sub-impedance scores at the plurality of selected frequencies according to the plurality of computed impedance values applied by the respective selected sensors.
Differentiating medical states based on plurality of computed sub-impedance scores
The method differentiates between at least two medical states of the subject according to the plurality of the computed sub-impedance scores.
Computer program product executing selection of AC frequency spectrum and impedance sensor electrode pair
The computer program product comprises code which, when executed while a feeding tube is in use, cause the processor to select a combination including a selected frequency spectrum of an alternating current and a selected electrode pair including at least one first electrode disposed on a distal end for feeding the subject and at least one second electrode contacting a surface of the skin, where the selected electrode pair denotes a respective selected impedance sensor positioned for sandwiching a lung and for avoiding passing current through the heart.
Computing impedance values and sub-impedance scores from voltage over impedance sensor
The code cause the processor to compute an impedance value according to voltage over the respective selected impedance sensor and according to the alternating current applied at the selected frequency spectrum, and compute a sub-impedance score according to the computed impedance value.
Iterating over new electrode pairs and additional selected frequencies to produce plurality of sub-impedance scores
The code causes the processor to iterate such that for each iteration another combination is selected that includes an electrode pair not previously selected in previous iterations and at least another selected frequency of the alternating current applied by the respective selected impedance sensor, for computing a plurality of computed sub-impedance scores at a plurality of selected frequencies.
Differentiating between at least two medical states using computed plurality of sub-impedance scores
The code causes the processor to differentiate between at least two medical states of the subject according to a plurality of the computed sub-impedance scores.
Across the independent claims, differentiation between at least two medical states is achieved by iteratively selecting electrode pairs and selected frequency spectra of alternating current for impedance sensing, computing impedance values from voltage and the applied alternating current, deriving sub-impedance scores, and differentiating medical states based on the plurality of computed sub-impedance scores using an electrode pair positioned for sandwiching a lung while avoiding passing current through the heart.
Stated Advantages
Avoiding passing current through the heart.
Positioning for sandwiching a lung.
Differentiation between at least two medical states of the subject according to computed sub-impedance scores.
Documented Applications
Real-time monitoring and differentiation of lung fluid change including pleural effusion and pulmonary edema using impedance and impedance-score decreases following fluid administration [procedural detail omitted for safety].
Differentiation between medical states based on computed sub-impedance scores for different clinically significant lung-fluid conditions.
Monitoring and differentiation using iterative impedance measurement with frequency spectrum selection, including potential mapping to clinically significant thresholds and trend-line extrapolation for impending accumulation risk (described in the document summary).
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