Method and device for respiratory monitoring

Abstract

A respiration monitoring system has deformation transducers on a flexible substrate arranged to adhere to a patient's torso. A processor receives signals in channels from the transducers and processes them to eliminate, reduce or compensate for noise arising from patient motion artefacts, to provide an output representative of respiration. The transducers have a size and a mutual location on the substrate so that a first transducer can overlie at least part of the 10th rib and a second transducer can overlie at least part of the 11th rib or the abdomen, and the processor processes data from the first transducer as being primarily representative of rib distending respiration and from the second transducer as being primarily representative of either diaphragm respiration or patient motion artefacts.

1 . A respiration monitoring system comprising:
 a flexible substrate,   an adhesive arranged on a surface of the flexible substrate to releasably adhere the flexible substrate to a patient's torso,   a plurality of embedded deformation transducers fixed to said flexible substrate including at least a first transducer and a second transducer, the first transducer and the second transducer being located on the substrate at an angle relative to a mutual location on the substrate,   the first transducer and the second transducer having a size and the mutual location on the substrate so that simultaneously the first transducer is configured to overlie at least part of a patient's 10 th  rib and the second transducer is configured to overlie at least part of a patient's 11 th  rib or abdomen, the transducers being positioned on the substrate to enable measuring both thoracic and abdominal displacement in a single location,   an electronic controller releasably mounted on the substrate, the electronic controller being positioned on a same side of both the first transducer and the second transducer, the electronic controller receiving signals by conductors from the first transducer and the second transducer, and   an accelerometer producing an output signal representative of a posture of the patient's torso,   wherein the electronic controller is configured to receive signals from the first transducer and the second transducer and to compensate for motion noise based on the output signal from the accelerometer, and to thereby derive an output representative of respiration based upon the signals from the first transducer and the second transducer.   
     
     
         2 . The respiration monitoring system of  claim 1 , wherein the system comprises a unitary sensor for adhering to a patient's skin, said sensor including:
 the substrate with the deformation transducers, and   the electronic controller,   wherein the electronic controller is included in a housing on the substrate with a signal conditioning circuit, and   wherein the electronic controller housing is releasably mounted on the substrate.   
     
     
         3 . The respiration monitoring system of  claim 1 , wherein the electronic controller is configured to trigger an artefact detection algorithm at regular intervals in which signals which are outside predetermined limits of measurement are removed. 
     
     
         4 . The respiration monitoring system of  claim 1 , wherein the electronic controller is configured to execute, when determining respiration rate, a frequency domain algorithm 
     
     
         5 . The respiration monitoring system of  claim 4 , wherein the electronic controller is configured to execute the frequency domain algorithm to take accelerometer data from the accelerometer as a secondary input and to compensate for cyclical interference from the subject or environment such as walking, by extracting frequency domain information from the accelerometer data. 
     
     
         6 . The respiration monitoring system of  claim 5 , wherein the electronic controller is configured to detect and compensate for movements using the accelerometer data. 
     
     
         7 . The respiration monitoring system of  claim 6 , wherein the electronic controller is configured to perform at least one of fall detection, step detection and orientation monitoring using the accelerometer data. 
     
     
         8 . The respiration monitoring system of  claim 1 , wherein the electronic controller is configured to detect inhalation and exhalation events and monitor lung capacity. 
     
     
         9 . The respiration monitoring system of  claim 1 , wherein the electronic controller is configured to execute, when determining respiration rate, a time domain algorithm. 
     
     
         10 . The respiration monitoring system of  claim 9 , wherein the electronic controller is configured to execute the time domain algorithm to produce a waveform represented by a repeating pattern of peaks and troughs at a rate indicative of the respiratory rate of the patient, and detect a distance between the peaks and a distance between the troughs in the waveform to derive the respiration rate. 
     
     
         11 . The respiration monitoring system of  claim 1 , wherein the electronic controller is configured to produce a waveform represented by a repeating pattern of peaks and troughs at a rate indicative of the respiratory rate of the patient. 
     
     
         12 . The respiration monitoring system of  claim 11 , wherein the electronic controller is configured to produce the waveform for diagnosis of dysfunctional breathing events in sleeping subjects by detecting portions of the waveform indicative of a dysfunctional breathing event. 
     
     
         13 . The respiration monitoring system of  claim 1 , wherein the electronic controller is configured to receive a unique identifier for a use with a particular subject, and to discontinue or erase said identifier upon removal of the substrate from the subject and/or re-charging for a next use. 
     
     
         14 . The respiration monitoring system of  claim 1 , wherein the first transducer and the second transducer are of equal length, width, thickness and composition. 
     
     
         15 . A respiration monitoring system comprising:
 a flexible substrate,   an adhesive arranged on a surface of the flexible substrate to releasably adhere the flexible substrate to a patient's torso,   a plurality of embedded deformation transducers fixed to said flexible substrate including at least a first transducer and a second transducer,   an accelerometer configured to produce an output signal representative of a posture of the patient's torso, and   an electronic controller releasably mounted on the substrate, the electronic controller configured to receive signals by conductors from the first transducer and the second transducer, to compensate for motion noise based on the output signal from the accelerometer, and to derive an output representative of respiration based upon the signals from the first transducer and the second transducer by executing a time domain algorithm.   
     
     
         16 . The respiration monitoring system of  claim 15 , wherein the electronic controller is configured to execute the time domain algorithm to produce a waveform represented by a repeating pattern of peaks and troughs at a rate indicative of the respiratory rate of the patient, and to detect a distance between the peaks and a distance between the troughs in the waveform to derive the respiration rate. 
     
     
         17 . The respiration monitoring system of  claim 15 , wherein the system comprises a unitary sensor for adhering to a patient's skin, said sensor including:
 the substrate with the deformation transducers, and   the electronic controller,   wherein the electronic controller is included in a housing on the substrate with a signal conditioning circuit, and   wherein the electronic controller housing is releasably mounted on the substrate.   
     
     
         18 . A respiration monitoring system comprising:
 a flexible substrate,   an adhesive arranged on a surface of the flexible substrate to releasably adhere the flexible substrate to a patient's torso,   a plurality of embedded deformation transducers fixed to said flexible substrate including at least a first transducer and a second transducer,   an accelerometer configured to produce an output signal representative of a posture of the patient's torso, and   an electronic controller releasably mounted on the substrate, the electronic controller configured to receive signals by conductors from the first transducer and the second transducer, to compensate for motion noise based on the output signal from the accelerometer, and to derive an output representative of respiration based upon the signals from the first transducer and the second transducer by producing a waveform represented by a repeating pattern of peaks and troughs at a rate indicative of the respiratory rate of the patient.   
     
     
         19 . The respiration monitoring system of  claim 18 , wherein the electronic controller is configured to produce the waveform for diagnosis of dysfunctional breathing events in sleeping subjects by detecting portions of the waveform indicative of a dysfunctional breathing event. 
     
     
         20 . The respiration monitoring system of  claim 18 , wherein the system comprises a unitary sensor for adhering to a patient's skin, said sensor including:
 the substrate with the deformation transducers, and   the electronic controller,   wherein the electronic controller is included in a housing on the substrate with a signal conditioning circuit, and   wherein the electronic controller housing is releasably mounted on the substrate.