[go: up one dir, main page]

WO2001078601A1 - Detection et classification de modeles de respiration - Google Patents

Detection et classification de modeles de respiration Download PDF

Info

Publication number
WO2001078601A1
WO2001078601A1 PCT/AU2000/000326 AU0000326W WO0178601A1 WO 2001078601 A1 WO2001078601 A1 WO 2001078601A1 AU 0000326 W AU0000326 W AU 0000326W WO 0178601 A1 WO0178601 A1 WO 0178601A1
Authority
WO
WIPO (PCT)
Prior art keywords
respiratory
signals
breath
patient
movement
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Ceased
Application number
PCT/AU2000/000326
Other languages
English (en)
Inventor
John William Ernest Brydon
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Resmed Pty Ltd
Original Assignee
Resmed Pty Ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Resmed Pty Ltd filed Critical Resmed Pty Ltd
Priority to PCT/AU2000/000326 priority Critical patent/WO2001078601A1/fr
Priority to AU42752/00A priority patent/AU4275200A/en
Priority to US10/257,316 priority patent/US6840907B1/en
Publication of WO2001078601A1 publication Critical patent/WO2001078601A1/fr
Anticipated expiration legal-status Critical
Ceased legal-status Critical Current

Links

Classifications

    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
    • A61B5/00—Measuring for diagnostic purposes; Identification of persons
    • A61B5/68—Arrangements of detecting, measuring or recording means, e.g. sensors, in relation to patient
    • A61B5/6887—Arrangements of detecting, measuring or recording means, e.g. sensors, in relation to patient mounted on external non-worn devices, e.g. non-medical devices
    • A61B5/6892—Mats
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
    • A61B5/00—Measuring for diagnostic purposes; Identification of persons
    • A61B5/08—Measuring devices for evaluating the respiratory organs
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
    • A61B5/00—Measuring for diagnostic purposes; Identification of persons
    • A61B5/103—Measuring devices for testing the shape, pattern, colour, size or movement of the body or parts thereof, for diagnostic purposes
    • A61B5/11—Measuring movement of the entire body or parts thereof, e.g. head or hand tremor or mobility of a limb
    • A61B5/113—Measuring movement of the entire body or parts thereof, e.g. head or hand tremor or mobility of a limb occurring during breathing
    • A61B5/1135—Measuring movement of the entire body or parts thereof, e.g. head or hand tremor or mobility of a limb occurring during breathing by monitoring thoracic expansion
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
    • A61B5/00—Measuring for diagnostic purposes; Identification of persons
    • A61B5/72—Signal processing specially adapted for physiological signals or for diagnostic purposes
    • A61B5/7235—Details of waveform analysis
    • A61B5/7264—Classification of physiological signals or data, e.g. using neural networks, statistical classifiers, expert systems or fuzzy systems
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
    • A61B2562/00—Details of sensors; Constructional details of sensor housings or probes; Accessories for sensors
    • A61B2562/02—Details of sensors specially adapted for in-vivo measurements
    • A61B2562/0247—Pressure sensors
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
    • A61B2562/00—Details of sensors; Constructional details of sensor housings or probes; Accessories for sensors
    • A61B2562/04—Arrangements of multiple sensors of the same type
    • A61B2562/043—Arrangements of multiple sensors of the same type in a linear array
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
    • A61B5/00—Measuring for diagnostic purposes; Identification of persons
    • A61B5/72—Signal processing specially adapted for physiological signals or for diagnostic purposes
    • A61B5/7235—Details of waveform analysis
    • A61B5/7239—Details of waveform analysis using differentiation including higher order derivatives
    • G—PHYSICS
    • G16—INFORMATION AND COMMUNICATION TECHNOLOGY [ICT] SPECIALLY ADAPTED FOR SPECIFIC APPLICATION FIELDS
    • G16H—HEALTHCARE INFORMATICS, i.e. INFORMATION AND COMMUNICATION TECHNOLOGY [ICT] SPECIALLY ADAPTED FOR THE HANDLING OR PROCESSING OF MEDICAL OR HEALTHCARE DATA
    • G16H50/00—ICT specially adapted for medical diagnosis, medical simulation or medical data mining; ICT specially adapted for detecting, monitoring or modelling epidemics or pandemics
    • G16H50/20—ICT specially adapted for medical diagnosis, medical simulation or medical data mining; ICT specially adapted for detecting, monitoring or modelling epidemics or pandemics for computer-aided diagnosis, e.g. based on medical expert systems

Definitions

  • the invention relates to respiratory-analysis mattresses and systems, and to methods of use thereof.
  • the invention further relates to the measurement of respiratory, cardiac and other movement related functions in patients suffering from a range of respiratory syndromes, including the disordered breathing associated with Cheyne Stokes syndrome, anaesthetic induced partial respiratory obstruction and sleep apnea.
  • Sleep apnea is a respiratory syndrome known to be present in about 8 % of the adult male human population and 4% of the adult female human population.
  • the syndrome manifests itself as the repetitive cessation of, or large reduction in, breathing while the patient is asleep - respectively termed apneas and hypopneas.
  • Apneas may be divided further into central apneas, where the cause of the apnea is the failure of the nervous system to activate the muscles responsible for respiration, and obstructive apneas, where the patient tries to breath but is prevented from doing so by the temporary collapse on inspiration of his or her upper airway.
  • the reasons for such collapses are not completely understood but may include a loss of tone in those muscles which hold the airway open plus an anatomical disposition towards a narrow upper airway. Prior to treatment the syndrome must be diagnosed.
  • a device used in this area is the Static Charge Sensitive Bed (SCSB) described in US 4,320,766 (Allihanka et al).
  • SCSB Static Charge Sensitive Bed
  • US 4,320,766 describes a mattress which outputs a single electrical signal that varies with the patient's movement. By suitable electrical filtering of the movement signal indications of body movement, respiration, snore and heartbeat are produced for subsequent display.
  • PNDF polyvinylidene fluoride
  • a PNDF film based device for detecting and recording snoring is also described in International Publication No. WO 96/36279 (Sullivan).
  • a limitation of the SCSB is that because of its inherent planar construction it cannot be used to localise the source of the movement it detects. Likewise, the above - mentioned devices also generate minimal spatial information. A major consequence of this is that the outputs of the said devices vary considerably with patient orientation.
  • the invention seeks to provide a respiratory-analysis mattress and system and associated method which overcome or at least ameliorates some of the deficiencies of the prior art.
  • the invention provides a respiratory analysis system for monitoring a respiratory variable for a patient, the system comprising: a sensor array for accommodating a patient to be in contact therewith, the array having a plurality of independent like sensors for measuring respiratory movement at different locations on the patient to generate a set of independent respiratory movement signals; and processing means receiving and processing said movement signals to derive a classification of individual breaths using, for each breath, the respective phases and/or amplitudes of the movement sensor signals within the set for that breath.
  • the invention further provides a method for monitoring at least one respiratory variable for a patient, the method comprising the steps of: measuring respiratory movement at different locations on a patient to generate a set of independent respiratory movement signals; and processing said movement signals to derive a classification of individual breaths using, for each breath, the respective phase and/or amplitude of each movement sensor signal within the set for that breath.
  • the invention yet further provides a respiratory analysis system for monitoring a respiratory variable for a patient, comprising: processor means receiving a set of patient respiratory movement signals to derive a classification of individual breaths using, for each breath, the respective phase and/or amplitude of each movement sensor signal within the set for that breath.
  • the sensor array includes the range three to ten such movement sensors.
  • the movement sensors can be formed by piezoelectric elements, for example polyvinylidene fluroride (PVDF) sensor strips.
  • PVDF polyvinylidene fluroride
  • pairs of electrodes opposed across the body of the patient, with said pairs severally distributed at different locations about the patient's torso, are used to measure the electrical resistance of the torso in the region of the said locations.
  • the measurement of said resistance which varies with respiratory and other movements, forms a form of movement signal.
  • an array of electrical coils each consisting typically of one turn are severally wound round the patient's torso in different locations, each said coil being connected to monitoring means that measures its inductance.
  • the measurement of said inductance which varies with respiratory and other movements, forms a form of movement signal.
  • an array of sealed tubes partially inflated with liquid or gas and of radius typically 3 cm and length typically 50 cm are located severally beneath the upper torso of the patient on the surface of the bed or within or underneath the mattress on which the patient is reclining, each said tube being connected to pressure measuring means that measures its internal pressure. The measurement of said pressure, which varies with respiratory and other movements, forms a form of movement signal.
  • the invention yet further provides a method for determining whether two breaths are similar comprising the steps of: monitoring a plurality of independent patient movement signals; identifying the portions of said signals which correspond to each breath; for said portions, calculating the phase and amplitude of corresponding periodic functions; determining a vector for each breath in accordance with said phases and amplitudes; calculating a measure of the correction between the vectors for the two breaths; and if said measure is greater than a threshold, determining that the breaths are similar.
  • said correlation is the dot product of the two vectors.
  • said threshold is 0.9.
  • the invention yet further provides a method for determining whether two breaths are different comprising the steps of: monitoring a plurality of independent patient movement signals; identifying the portions of said signals which correspond to each breath; for said portions, calculating the phase and amplitude of corresponding periodic functions; determining a vector for each breath in accordance with said phases and amplitudes; calculating a measure of the correlation between the vectors for the two breaths; and if said measure is less than a threshold, determining that the breaths are different.
  • said correlation is the dot product of the two vectors.
  • said threshold is 0.6.
  • Fig. 1 is a schematic overview of a respiratory-analysis system to be described below;
  • Figs. 2a and 2b are respectively plan and side views of a movement-sensitive mattress forming part of the system;
  • Fig. 3 is a cross-sectional view through the movement-sensitive mattress
  • Fig. 4a is a cut-away schematic drawing of the movement-sensitive mattress showing the internal sensor strips
  • Figs. 4b and 4c are top views of further embodiments of movement-sensitive mattresses;
  • Fig. 5 illustrates the use of the movement-sensitive mattress to produce a multichannel electrical signal indicating the displacement of the patient's body near the sensor strips;
  • Fig. 6 illustrates a sequence of displacements of the patient's body associated with normal breathing
  • Fig. 7 illustrates a sequence of displacements of the patient's body associated with disordered breathing
  • Figs. 8a and 8b are respectively schematic cross-sectional and plan views of one of the sensor strips
  • Figs. 9a and 9b show the connection means of a sensor strip respectively before and after connection of the sensor strip thereto;
  • Figs. 10a and 10b show the connection means with the sensor strip attached, but respectively before and after attachment of a rigid pressure plate
  • Figs. 11a and l ib show the connection of a coaxial cable to the connection means;
  • Fig. 12a shows the attachment of the sensor strip to the connection means;
  • Fig. 12b is a cross-section taken along A - A' in Fig. 12a;
  • Fig. 13 shows an alternative embodiment in which the sensor strips are connected to a single bus board instead of to individual circuit boards;
  • Figs. 14a to 14d show the connection of the sensor strip (via the coaxial cable shown in Figs. 11a and l ib, but omitted from Figs. 14a to 14d) to four alternative embodiments of sensor buffers;
  • Fig. 15 shows the connection of the sensor strips to computing means via strip connection means, sensor buffers, gain stages, and an analog to digital converter;
  • Fig. 16 shows pre-processing means for deconvolving input digital signals to produce output pre-processed digital signals
  • Fig. 17 illustrates the deconvolution of a channel by subtraction of a fraction of the signal on that channel from the two adjacent channels in order to sharpen the spatial response of the channels
  • Fig. 18a illustrates the calculation of diagnostic signals from the pre-processed digital signals using basic processing means followed by diagnostic processing means;
  • Fig. 18b-f show plots of cross correlation with historical time;
  • Fig. 18g shows traces of a processed displacement signal and a sine wave approximation;
  • Fig. 19 shows the output of diagnostic signals to display means;
  • Fig. 20 shows the control of a Continuous Positive Airway Pressure (CPAP) flow generator by the new system
  • Fig. 21 shows a polygraph input means connected to the computing means, for allowing diagnostic information to be displayed on a polygraph using a spare analogue input channel of the polygraph;
  • Figs. 22a and 22b show graphs of voltage against time, and the tracing of symbols on the polygraph display
  • Fig. 23 shows the output of alphanumeric forms of diagnostic variables to the polygraph display ;
  • Fig. 24 shows an alternative means of providing a plurality of sensor strips, in which the sensor strips are integrally formed from a single PVDF sheet;
  • Fig. 25 shows conductive tracks on the embodiment of Fig. 24;
  • Fig. 26a shows an alternative to the embodiment of Figs. 24 and 25, in which the sensor strips, are cut from a narrower PVDF sheet and then folded through 90° as shown in the next figure;
  • Fig. 26b shows the folding of the sensor strips through 90° while remaining integrally connected to a tail strip
  • Figs. 27a and 27b show an embodiment which is the same as that of Fig. 26, except that a broader tail strip is used, so that the tail strip can be folded beneath the sensor strips to provide greater support;
  • Fig. 28 and 29 show conductive strips on the embodiment of Fig. 26;
  • Fig. 30 shows the metallisation on each side of one of the sensor strips
  • Fig. 31 shows the sensor strips wrapped around one edge of a foam sheet 18;
  • Figs. 32a, 32b and 32c show movement-sensitive sheets comprising the embodiments of any of Figs. 24 to 30;
  • Fig. 33 shows the movement-sensitive sheet of Fig. 32a mounted on a carrier sheet, which can be in the form of a conventional fitted sheet;
  • Figs. 34 and 35 show an alternate arrangement of respiratory movement sensors
  • Fig. 36 shows connection of the sensors of Figs. 34 and 35 to computing means
  • Figs. 37 and 38 show a yet further arrangement of respiratory movement sensors
  • Fig. 39 shows connection of the sensors of Figs. 37 and 38 to computing means
  • Figs. 40 and 41 show a yet further arrangement of respiratory movement sensors; and Fig. 42 shows connection of the sensors of Figs. 40 and 41 to computing means.
  • Fig. 1 gives an overview of a system 101 which measures the body movements of a reclining person and from those measurements determines parameters of his or her respiratory, cardiac and other movement-related functions.
  • the aforesaid parameters can be used to diagnose a range of respiratory disorders, in particular those associated with sleep apnea.
  • the system can be used both in a hospital and in a patient's home.
  • the system 101 comprises sensor means 102 which generates electrical signals in response to movement of a reclining person, interface means 103 which converts the said signals into a form that can be processed by the computing means 104 (Fig. 1).
  • the computing means 104 processes the said signals to produce the above-mentioned respiratory and movement parameters which are then further combined to produce parameters diagnostic of respiratory disorders associated with various types of sleep apnea.
  • the function of the computing means 104 is determined by the control means 105, which is operated by medical staff who are directing the use of the system.
  • the aforesaid processing can be in real time, that is at the same time as the said signals are being recorded, or in a review process where the said recorded signals are recalled from storage and processed at some time after their acquisition.
  • Some or all of the diagnostic parameters can then be displayed using a display means 106, recorded for subsequent review on computer disk by a recording means 107, printed using a printing means 108, transmitted to another location using a transmission means 109 and output to a recording polygraph by polygraph input means 110. Additionally, if a particular preset condition of the diagnostic parameters is met a video camera 111 can be switched on to record moving or stationary video images of the patient's body position and movements. Alternatively, or optionally, a similar or different preset condition can activate an alarm means 112 to indicate to another person the occurrence of the said preset condition.
  • An external Constant Positive Airway Pressure (CPAP) flow generator may optionally be controlled via CPAP control means 113. Sound output means 114 may be used to listen to snore signals, either in real time or on subsequent replay of data.
  • CPAP Constant Positive Airway Pressure
  • sensor means 102 comprises a movement-sensitive mattress 2 which can rest on top of a conventional mattress 3 on which the patient 1 lies.
  • Fig. 2b shows the movement-sensitive mattress 2 above the conventional mattress 3 , but this could alternatively be below the conventional mattress 3.
  • the 5 patient's head may optionally rest on a pillow 4.
  • movement-sensitive mattress 2 comprises a sandwich of low density polyethylene foam 7 enclosed by a neoprene envelope 6 constructed in such a way that movements of the patient's body cause stretching of the neoprene envelope 6.
  • a affixed to the inside surface of the top side of the neoprene envelope 6 are a number of sensor strips 5 , arranged in one or more patterns that span most of the patient's body. The patterns may run laterally across the movement-sensitive mattress as illustrated, or vertically from head to toe, or a combination or superposition of both. Electrical signals are conducted from the sensor 15 strips 5 by sensor strip connectors 42.
  • three sensor strips 5 arranged to be level with the patient's rib cage area are required to obtain useful electrical signals utilised for subsequent processing.
  • a typical range is between three and ten sensors.
  • Fig. 4b six sensor strips 5' are arranged in a spaced-apart configuration. 20
  • the sensor strips are formed in the same manner as those shown in Fig. 4a, however are substantially shorter than the width of the mattress 2.
  • a signal is taken off from each sensor strip 5 ' .
  • the signals act as spot strain gauges.
  • Fig. 4c the same six senor strips 5' are connected to a common bus connector 5a that provides for individual take-off points for each sensor strip. 25
  • a multichannel electrical signal is derived, the channels of which reflect the localised displacement of the patient's body in the vicinity of each of the sensor strips 5, as indicated in Fig. 5.
  • the movement of the body during, for example, respiration may be monitored.
  • This therefore, provides a means of imaging the displacements of the torso, particularly with regard to respiration, in a 30 reclining patient.
  • the system is largely insensitive to patient orientation on the movement-sensitive mattress 2.
  • the sensor strips 5 are constructed of a layer of polyvinyledene fluoride (PVDF) film 11 , a supporting mylar film 13, an adhesive layer 8 to join together the said films and an adhesive layer 41 to adhere the resulting assembly to the inside surface of the neoprene envelope 6, as shown in Fig. 3.
  • PVDF polyvinyledene fluoride
  • the PVDF film 11 has the property whereby an electrical charge is generated across the faces of the film 11 when a mechanical strain is applied along the length of the film 11
  • the electrical charge is conducted from the surface of the layer PVDF film 11 by two conductive, metallised surface layers, a first layer 10 and the second layer 12 which are affixed to opposing faces of the film 11 during its manufacture.
  • the mylar film 13 acts as a physical support for the PVDF film 11 and regulates the amount of strain applied to the said film when the sensor strip 5 is stretched.
  • the mylar film 13 also has applied on one face a conductive, metallised surface layer 14 which is used to screen the second conductive layer 12 of the PVDF film 11 from external electrical interference.
  • the first conductive layer 10 of the said PVDF film 11 is externally connected to the metallised layer 14 of the mylar film 13 so that the second conductive layer 12 of PVDF film 11 is effectively screened on both sides from electrical interference.
  • each sensor strip 5 Typical dimensions of each sensor strip 5 are 650 mm long by 12 mm wide.
  • the PVDF film is typically 28 ⁇ m in thickness and the mylar film 13 typically 1 mil in thickness.
  • the sensor strip 5 can, for example, be made up from the above-mentioned films by the AMP Corporation of PO Box 799, Valley Forge, PA 19482, USA, as a modification of their standard range of piezoelectric film products.
  • connection means 42 makes connections to the first conductive layer 10 and second conductive layer 12 of the PVDF film 11 and the metallised layer 14 of the mylar film 13, and, further, electrically connects first conductive layer 10 and metallised layer 14 together for electrical screening purposes.
  • the resultant two electrical paths are connected to a coaxial cable 33 for transmission to interface means 103.
  • Sensor strip connection means 42 comprises a double sided printed circuit board 18 with a contact area 19 that makes electrical contact via conductive adhesive with a conductive area 15 (see Fig. 8a) of the metallised layer 14 of the mylar film 13; a contact area 20 that makes electrical contact with a conductive area 16 of the second conductive layer 12 of the PVDF film 11 ; and a contact area 21 that makes electrical contact with the first conductive layer 10 of the PVDF film 11 by means of a conducting bridge 30 described below.
  • the electrical signal from the conductive area 16 of second conductive face 12 of PVDF film 11 , connected to sensor strip connection means 42 via contact area 20 is conducted from the said contact area to connecting pad 23 via copper track 24 located on the reverse side of printed circuit board 18.
  • the electrical signal from first conductive layer 10 of PVDF film 11 is connected to the conducting copper top face of contact area 21 of printed circuit board 18 by a conducting bridge 30 constructed from copper tape with conductive adhesive on its contact side.
  • the electrical signal from the conducting copper top face of printed circuit board 18 is conducted to a connecting pad 25 on the printed circuit board 18.
  • conducting bridge 30 and the two other aforementioned sensor strip connections are maintained in a state of intimate connection with their respective contact areas 19, 20, 21 by a non-conducting, rigid pressure plate 31 which bears down on the aforementioned contact assemblies by virtue of two pressure springs 32.
  • a connecting pad 23 on the printed circuit board 18 is soldered or otherwise electrically attached the inner conductor 35 of a coaxial cable 33.
  • To connecting pad 25 is soldered or otherwise electrically attached the outer screening conductor 34 of the coaxial cable 33.
  • the coaxial cable 33 is attached to circuit board 18 by a method which simultaneously stress relieves the soldered connections and locates the cable 33.
  • the coaxial cable 33 is located over cable location tongue 27 (as illustrated in Fig.s 11a & lib), sourced from circuit board 18 by two parallel slots 28.
  • This arrangement allows a heatshrink sleeve 36 to be pushed simultaneously over the coaxial cable 33 and the cable location tongue 27 so that, on the application of heat, the reduction in diameter of the heatshrink sleeve 36 pulls the coaxial cable 33 into intimate and stable contact with the cable location tongue 27.
  • Adhesive on the interior of the heatshrink sleeve 36 plus its physical grip when shrunk ensure that the coaxial cable 33 is clamped sufficiently for there to be no strain on its internal conductors 34 and 35.
  • the circuit board 18 is attached to the interior of the neoprene envelope 6 using a novel arrangement of adhesive that reduces the strain on the electrical connections between the sensor strip 5 and the circuit board 18.
  • the sensor strip 5 is attached to the circuit board 18 using adhesive in location 40; adhesive barrier slot 29 is cut in the said circuit board to prevent adhesive from location 40 straying into contact area 19.
  • Adhesives in the location 40 and subsequently described are all of a high strength cyano-acrylic gel type such as that sold under the registered trademark " Loctite 454" .
  • the sensor strip 5 is attached to the neoprene envelope 6 along its length by an adhesive strip 41 , for example the transfer adhesive sold under the registered trademark "3M type 9460" .
  • the circuit board 18 is constructed with two strain relief horns 26 which are attached to the interior surface of the neoprene envelope 6 using the above-mentioned cyano-acrylic adhesive applied at locations 37.
  • the function of the strain relief horns 26 is to limit the stretch of the neoprene envelope 6 in the vicinity of the attachment of the circuit board 18 to the sensor strip 5 thus significantly reducing the strain on the aforementioned electrical connections with the strip 5.
  • the sensor strip 5 can additionally be stabilised by the application of the said cyanoacrylic adhesive at location 39.
  • the remainder of circuit board 18 is attached to the neoprene envelope 6 using said cyano-acrylic adhesive in at least locations 38.
  • an alternative embodiment 93 combines circuit boards 18 in parallel on to one long bus board 94 or circuit strip such that the individual connections to strips 5 are conducted in parallel to a single multichannel connector 95 to which is connected a single multicore cable 96 which conducts all the signals from sensor strips 5.
  • sensor buffers 43 described below may be located in close proximity to the bus board 94.
  • the sensor buffer 43 can be of the form where an operational amplifier 51 operates as a charge amplifier (as shown in Fig. 14a), balancing charge received from sensor strip 5 in response to the patient's movement, against charge built up on a capacitor 52 from operational amplifier output 54.
  • This design is commonly used in such situations and referenced in "Piezo Film Sensors Technical Manual O/N: 6571” published by the AMP Corporation of PO Box 799, Valley Forge, PA 19482, USA. This Technical Manual also indicates the necessity of using silicon diodes 55 (as shown in Fig.
  • protection diodes 55 in the above-mentioned configuration does however have a drawback, namely the reverse leakage current of the diodes 55 flows into the virtual earth 46 of the operational amplifier 51 which results in a compensating offset voltage at the output 54 of the operational amplifier 51.
  • the input 47 of the sensor strip 5 to the operational amplifier 51 in the above-mentioned charge amplifier configuration is a virtual earth 46, that is the negative feedback of the operational amplifier 51 acts to maintain the voltage at the input 47 at zero.
  • the input voltage at input 47 may be a small number of millivolts because of constructional imperfections within the operational amplifier 51.
  • the input impedance of such a virtual earth is very low (because the operational amplifier acts to drain away charge in order to maintain the virtual earth) - some tens of ohms at the most, therefore an external impedance can be placed between the virtual earth point 46 and ground 99 and, providing said impedance is larger than about 1000 ohms, that is, large relative to the virtual earth impedance, the functioning of the charge amplifier is unaffected.
  • This allows a combination of parallel 56 and serial 57 impedances to replace the above-mentioned reverse biased diodes 55 connecting the virtual earth 46 to the above-mentioned operational amplifier supply rails ( ⁇ V).
  • the voltage on the sensor strip 5 produced by the accumulation of charge due to a large impulsive force applied thereto may be large - of the order of 100 volts - the effective source impedance of the sensor
  • silicon diodes 46 can be used back to back between the virtual earth 46 and ground 99 (as shown in Fig. 14d). Under non-overload conditions the voltage across the diodes 46 is insufficient for them to conduct, hence they are invisible to the charge amplifier circuit. Under overload conditions one of the diodes 46 will conduct if the voltage increases above about 0.5 volts, thus limiting the overload voltage applied to the input 47 of operational amplifier 51.
  • a parallel resistor 47a of about 1 Mohm can be placed in parallel with the diodes 46 to provide bias current for the operational amplifier inputs, thereby relieving the above-mentioned magnitude constraint on DC feedback resistor 53.
  • DC feedback stabilisation resistor 53 in conjunction with feedback capacitor 52 forms a highpass filter with an effective - 3 dB frequency of approximately 0.1 Hz.
  • the outputs 54 of the charge amplifiers 43 are then passed through a further gain stage 44 (see Fig. 15) which comprises a low pass filter with a -3 dB frequency ⁇ o point of approximately 100 Hz.
  • the outputs of gain stages 44 are input to a multichannel Analog to Digital Converter (ADC) 45 which has at least as many inputs as there are sensor strips 5.
  • ADC Analog to Digital Converter
  • the ADC converter 45 transforms each of the inputs to a numerical digital signal 58 for subsequent processing and storage with a precision of at least 12
  • the digital output signals 58 of the ADC 45 are input to computing means 104 which processes the inputs and which stores the digital outputs to computer disk 107 for subsequent retrieval.
  • one or more external electrical inputs 48,49 are provided to permit
  • signals derived from the movement- sensitive mattress 2 are, typically, the output from an oximeter (not shown) attached to the finger or ear of the patient, and the output from a pressure transducer (not shown) connected to a mask on the patient's face or nasal prongs inserted in the patient's nares in order to detect respiration.
  • External electrical inputs 48,49 are connected to combination buffer amplifiers and low pass filters 50 the outputs of which are connected to the inputs of the ADC 45 in parallel with the above-mentioned sensor strip gain stages 44 for similar conversion to digital outputs 45 but at sampling rates typically lower, say at 50 Hz.
  • pre-processing means 59 (forming part of the computing means 104) to produce pre-processed digitised signals 60.
  • the pre-processing means 59 acts both temporally on each individual channel of the digitised signals and spatially on two or more of the digitised signals in concert.
  • the pre-processing means 59 acts on each channel of digitised signals 58 firstly to equalise the gains of each channel, that is, to remove the variation in amplitude and phase response of each sensor strip 5 relative to the other sensor strips 5 , and secondly and optionally to deconvolve the signal of each sensor strip 5 from the effects of adjacent strips 5 (as shown in Fig. 17).
  • the signals are output as pre-processed digitised signals 60.
  • the above-mentioned deconvolution comprises the subtraction from at least each adjacent channel 63 adjacent to the channel 62 being deconvolved, of a precalculated fraction of the signal measured in said channel 62 such as to remove from said adjacent channels 63 any signal contribution due to physical pressure 61 exerted on the sensor strip 5 corresponding to the channel 62 being deconvolved.
  • the effect of this procedure is to localise or " sharpen" the spatial response for each channel.
  • the pre-processed digitised signals 60 are then separately input in parallel to a number of basic processing means 64,66,68,70,72,74,76,78,80,82,97,134 and 136 (again forming part of computing means 104) whose function is to extract particular features from the digitised signals, the features subsequently being used in combination to obtain a diagnosis.
  • basic processing means 64,66,68,70,72,74,76,78,80,82,97,134 and 136 (again forming part of computing means 104) whose function is to extract particular features from the digitised signals, the features subsequently being used in combination to obtain a diagnosis.
  • Some of said basic processing means act temporally on each individual channel of the said digitised signals while others act spatially in concert on two or more of the said pre- processed digitised signals.
  • Basic processing means 64 acts on one or more of pre-processed digitised signals 60 to produce a basic derived signal 65 which is a measure of the sum total of the patient's movement, regardless of polarity.
  • the basic derived signal 65 is a measure of the patient's instantaneous respiratory effort ER and is calculated as:
  • Basic processing means 66 acts on one or more of pre-processed digitised signals 60 to produce a basic derived signal 67 which is a measure of the integral over a complete breath, or the summed separate integrals over the inspiratory and the expiratory phases, of the sum total of the patient's movement, regardless of polarity.
  • the basic derived signal 67 is a measure of the patient's total respiratory effort TR for the breath and is calculated as:
  • Respiratory Phase Basic processing means 68 acts on one or more of pre-processed digitised signals 60 to produce basic derived signal 69 which is a measure of the respiratory phase of the patient.
  • the basic derived signal 69 indicates at what point in the inspiration expiration cycle the pre-processed digitised signals 60 are being measured and may be calculated in one instance by fitting retrospectively in time a sine wave, as a function of time, to the largest in amplitude of pre-processed digitised signals 60.
  • the basic derived signal 69 associated with specific pre-processed digitised signals 60 is then calculated as the phase angle at whichever point on the aforementioned sine wave coincides temporally with the measurement point reached in said pre-processed digitised signals.
  • Basic processing means 70 acts on one or more of pre-processed digitised signals 60 to produce basic derived signal 71 which is a measure of the spatial respiratory zero phase point of the patient.
  • the basic derived signal 71 indicates at what position on the movement-sensitive mattress 2 the patient's body changes from exerting positive to negative pressure and changes significantly with the patient's mode of breathing.
  • the signal is calculated as the sensor strip 5 index (n) at which the sums of the positive and negative displacements are equal within a prescribed error, namely: n is "zero phase point'
  • Basic processing means 72 acts on one or more of pre-processed digitised signals 60 to produce basic derived signal 73 which is a measure of the average displacement (PR) of the patient.
  • the basic derived signal 73 indicates the degree that the thorax and abdomen of the patient are free to move independently of each other and is thus sensitive to the transition from unobstructed to obstructed, that is, so called paradoxical, breathing efforts.
  • Such a signal may be calculated as:
  • Basic processing means 74 acts on one or more of pre-processed digitised signals 60 to produce basic derived signal 75 which is a measure of the snore amplitude of the patient.
  • a signal indicative of snore amplitude may be calculated by passing each channel of the aforesaid pre-processed digitised signals through a digital high pass filter with a low frequency cut-off of approximately 10 Hz, then calculating the modulus of each resulting signal, then summing all the moduli and passing the sum through a low pass filter with a high frequency cut-off of between 0.5 and 2 Hz.
  • Basic derived signal 75 is the resultant output of the aforesaid low pass filter.
  • Basic processing means 76 acts on one or more of pre-processed digitised signals 60 to produce basic derived signal 77 which is a measure of the harmonic purity of the patient's snore, that is, its closeness in form to a simple sine wave.
  • the basic derived signal 77 varies with the type of snore - a non-obstructive snore having a different degree of harmonic purity than an obstructive one.
  • a signal indicative of such above-mentioned snore harmonic purity may be calculated by passing each channel of the aforesaid pre-processed digitised signals 60 through a digital high pass filter with a low frequency cut off of approximately 10 Hz, then selecting the channel with the highest resulting highest amplitude and calculating the instantaneous phase of the signal by, for example, deriving the " analytic" signal from the input signal by passing it through a 90 deg phase shift filter, then differentiating the instantaneous phase, then low pass filtering the resultant differential and differentiating again.
  • Basic derived signal 77 is the resultant output, being inversely proportional to the purity of the snore harmonic content.
  • Basic processing means 78 yet further acts on one or more of pre-processed digitised signals 60 to produce basic derived signal 79 which is a measure of the harmonic stability of the patient's snore, that is, the accuracy with which one cycle of the snore signal matches its predecessor.
  • the basic derived signal 79 varies with the type of snore - a non-obstructive snore having a different degree of harmonic stability than an obstructive one.
  • a signal indicative of such above-mentioned snore harmonic stability may be calculated by passing each channel of the aforesaid pre-processed digitised signals 60 through a digital high pass filter with a low frequency cut off of approximately 10 Hz, then selecting channel with the highest resulting highest amplitude and autocorrellating the signal.
  • the basic processing means 80 acts on one or more of pre-processed digitised signals 60 to produce basic derived signal 81 which is a measure of non-respiratory movements of the patient.
  • the basic derived signal 81 may be calculated by passing each channel of the pre-processed digitised signals 60 through a digital band pass filter with a pass band of approximately 10 to 40 Hz, then calculating the modulus of each resulting signal, then summing all the moduli and passing the sum through a low pass filter with a high frequency cut off of between 2 and 10 Hz.
  • Basic derived signal 79 is the resultant output of the aforesaid low pass filter.
  • Basic processing means 82 also acts on one or more of pre-processed digitised signals 60 to produce basic derived signal 83 which is a measure of the heartrate of the patient.
  • the basic derived signal 83 may be calculated by passing each channel of the aforesaid pre-processed digitised signals through a digital band pass filter with a pass band of approximately 5 - 15 Hz, then selecting the channel with the highest resulting highest amplitude and detecting the ballistocardiogram impulse associated with each heartbeat using a matched filter or similar technique.
  • the aforementioned time interval can be divided by two to give a value within the bounds of physiologic possibility.
  • the abovementioned bandpassed signals may be correlated against past time sets of the same signals in an identical way to that used to determine respiration rate (as described below), to determine basic derived signal 83, the heartrate.
  • the basic processing means 134 acts on one or more of pre-processed digitised signals 60 to produce basic derived signal 135 which is a measure of the amplitude of the cardioballistogram of the patient.
  • the basic derived signal 135 may be calculated as the unnormalised output of the matched filter correlation technique used to calculate basic derived signal 83, measured at a time coincident with the maximum of basic derived signal 83.
  • Basic processing means 97 yet further acts on one or more of pre-processed digitised signals 60 to produce basic derived signal 98 which is the spatial respiratory maximum effort point of the patient.
  • the signal is calculated as the sensor strip 5 index at which the integral over a complete breath of the sum total of the patient's movement, regardless of polarity, is a maximum.
  • An alternative calculation is
  • a further basic processing means can act on pre-processed digitised signals 60 to produce a further basic derived signal (not shown) which is a measure of the prevailing respiratory rate.
  • This basic derived signal is calculated by correlating the spatial "shape" of the sensor pattern at any given time with the "shapes" of the sensor pattern in past time; the first occurrence of a good correlation (with a coefficient greater than a preset value, typically 0.9) indicates at what time previously a similar pattern occurred, that is, the current respiration rate.
  • each channel of the aforesaid preprocessed digitised signals 60 is passed through a low pass digital filter with a high frequency cutoff of approximately 2 Hz and, optionally, the sampling rate of the said filtered signals is decimated down to approximately 20 Hz for subsequent computing convenience.
  • the current spatial set of filtered sensor signals, ⁇ S n (t) is cross correlated against the sets sampled at previous times to give a correlation function:
  • laboured breathing is meant a physical exertion, associated with inspiration or expiration, that is significantly greater than the normal exertions of breathing. In one patient subgroup, such laboured breathing is caused by an increase in upper airway resistance, particularly on inspiration.
  • processing of the aforementioned higher frequency component has been limited to bandpass filtering prior to display as a time varying trace on an oscilloscope or polygraph.
  • the trained observer can estimate by eye that a degree of laboured breathing exists but cannot quantify it or diagnose its extent automatically because the magnitude of the signal varies with such parameters as the orientation of the subject with reference to the sensor, his or her size and shape.
  • One or more of the electrical signals 44 from the movement sensitive bed sensor strips 5 or preprocessed signals 60 are passed through an analog or digital Effort Filter with a passband that rejects both the low frequency signals, predominantly produced by basic respiration, and the high frequency signals produced by snoring and cardiac action.
  • the pass band of the said Effort Filter is from 4 Hz to 10 Hz and after the filter the modulus of the signal is taken and the resulting signal low pass filtered at about 4 Hz to give a signal proportional to the amplitude of the original bandpassed one.
  • the output of the Effort Filter is then subjected to two, parallel processes - firstly the said output is averaged over the entire duration of each respiratory phase, that is, separately over the inspiratory phase and the expiratory phase, and secondly, the maximum amplitude reached by the said output within each respiratory phase is measured and stored. These measurements are termed, respectively, the Average Respiratory Phase Effort and the Maximum Respiratory Phase Effort.
  • the said Effort measurements can be displayed and stored in their own right or, preferably used as inputs to further processing described below.
  • a significant improvement is offered over existing systems in that there is provided a method of measuring the extent of laboured breathing and determining objectively the degree thereof.
  • Such an embodiment of the invention is amenable to use within automatic respiratory diagnostic systems.
  • This embodiment consists of the further processing of the cross correlation signal used to determine the respiratory rate.
  • the aforesaid signal is the output of a process that correlates the set of sampled signals from the sensor strips 5 with previous sets of the same signals, stored back in time. For regular breathing, there will be a point in time, one breath back, where the values of the sampled set of sensor signals will be almost identical to the current set. This is evident in the output of the amplitude normalised cross correlation described in the original provisional patent.
  • Fig. 18b shows the outputs of the said cross correlation with increasing time into the past. In Fig. 18b expiration or inspiration has just started and correlation between the current signal set and its immediate predecessors quickly declines. One breath back, correlation again increases towards + 1.0, enabling the current respiration rate to be measured as time, Ti , between correlation threshold levels TH j .
  • the system monitors the value of the above past time cross correlation signal with time. As time into the inspiration or expiration progresses, the values of each time sampled set of strip signals stabilises, giving an increased span of correlation with the immediate past signals. This is observable in Fig.s 18b-d, where the time into the past, T 2 , for the cross correlation signal to fall from a good correlation of almost + 1.0 to the negligible correlation threshold, TH 2 , increases with time. At the end of the respiratory phase, significant past correlation time,T 2 , is at a maximum (Fig.
  • the processing system monitors the value of the said past correlation time and compare it continuously with a threshold value of typically 70% of the maximum reached. When the value of the said time drops below that of the said threshold the end of inspiration or expiration is indicated.
  • the system determines the elapsed time between the last two indications of respiratory phase change of method immediately above. This elapsed time is the current breath time, effectively measured at every half breath interval.
  • This characteristic is used to distinguish between relatively unrestricted respiration and highly restricted or totally obstructed, so-called paradoxical respiration, in which there can be a significantly more gradual decline in past time away from correlation, and, in which the correlation value no longer approaches the anti-correlation level of -1.0 (Fig. 18f).
  • the present invention takes the past time correlation values as shown in Figs 18f and 18g and performs two processes in parallel. Firstly, the said values are averaged over the period from the present back in time to the point prior to the last complete breath that the said values fall to a level of insignificant correlation, typically zero: this is indicated by time, T, in Figs 18e and 18f.
  • the arithmetic modulus of the said values is subjected to averaging over the same, aforementioned period.
  • the abovementioned averaging period can cover the time between the first fall in past time of the correlation value below the threshold of significance and the similar fall for one breath into the past (not indicated).
  • the abovementioned averages are termed, respectively, the Past Breath Correlation Mean and the Past Breath Correlation Modulus Mean.
  • the Past Breath Correlation Mean is then compared with a threshold close to zero, typically, 0.25. If the said Mean exceeds the said threshold then the breath is deemed to be abnormal, that is, the inspirational correlation profile does not match in antiphase that of the expiration.
  • the Past Breath Modulus Mean is compared with a threshold close to 1.0, typically 0.8. If the said Sum exceeds the said threshold then the breath is deemed to be normal, that is, the correlations during inspiration are antiphase to those during expiration.
  • the preprocessed digitised signals 60 can be further used to classify a particular pattern of breathing for subsequent comparison with future pattern or patterns. Such a comparison is advantageous in that it can be used to detect the change, for example, from unobstructed respiration to partially obstructed respiration or the onset of an attempt to breath against a completely obstructed airway, the latter being termed 'paradoxical breathing' .
  • the basic processing means 136 firstly identifies a set of the pre-processed digitised signals 60 that make up a complete, single breath. In one implementation this is effected by utilising data assembled in the previously described cross correlation method of determining respiratory rate (i.e. "Respiratory Rate").
  • Fig. 18b can be seen a typical past time correlation graph of digitised signals 60.
  • the selected crossing points of the correlation function with correlation threshold, TH1 delineate the passage in time of one complete breath.
  • the set of digitised signals 60 that lie between these two intersections, and over which the respiration interval, TI is measured, forms, therefore, a sample of a complete breath at that particular moment in time. This sample of digitised signals 60 will be referred to as:
  • / ' indicates the sensor strip index
  • nT is the sample period time past the start of the aboveselected breath.
  • the selected breath is or approximates to one complete cycle of respiration.
  • the magnitude of each of the sensor signals, si will follow a cycle that starts at a particular amplitude, follows a repetitive pattern, then ends up at that same starting 5 amplitude.
  • the basic processing means 136 determines, for each sensor signal in the selected breath, its phase with respect to that breath and the amplitude of its fundamental frequency component. This is effected by first multiplying each signal, Si, by a sine signal, then a cosine signal (not shown) of unit amplitudes and with periods ⁇ o that equal the duration of the breath, ⁇ .
  • the signal S is identified by the trace having numeral 140 in Fig. 18g, and the sine signal is represented by the trace having numeral 141 in Fig. 18g.
  • the resulting summations give the in-phase and quadrature components of the required fundamental frequency component:
  • ⁇ is the duration of the selected breath.
  • the breath may, thus, be classified in terms of its duration, ⁇ , and the set of abovecomputed vectors, _ ⁇ i , which encapsulate information about the phasing and amplitude of each strip relative to the others.
  • a reference point for the phase may be specified by defining the phase angle of the strip with the largest magnitude as 0 degrees and adjusting the angles of the other vectors accordingly.
  • the magnitude of the set may be normalised by summing the squares of the vector magnitudes and computing the square root of that sum, then dividing each magnitude by that normalisation factor:
  • This set is provided to the diagnostic processing means 84 as the signal 137.
  • the basic derived signals 65, 67, 69, 71, 73, 75, 77, 79, 81, 83, 98, 135, plus the abovementioned respiratory rate, laboured breathing, respiratory phase change, alternate respiratory rate, detection of abnormal breathing signals and classification of breathing patterns and detection of altered breathing patterns are, in turn, input to diagnostic processing means 84 (forming part of computing means 104) which acts on one or more of the said basic derived signals to produce diagnostic signals 85 through 92.
  • Occurrence of Obstructive Apnea Diagnostic signal 85 is indicative of the occurrence of an obstructive apnea. This may be determined from the following states of the above-mentioned basic derived signals:
  • Diagnostic signal 86 is indicative of the duration in time of the above- mentioned obstructive apnea. This is calculated only if diagnostic signal 85 indicates 5 the occurrence of an obstructive apnea and typically may be determined from the length of time of the coincidence of a reduction in basic derived signal 73 (respiratory displacement) compared with 5 minute moving average of basic derived signal 73 (respiratory displacement), an increase in basic derived signal 65 (respiratory effort) compared with 5 minute moving average of basic derived signal 65 (respiratory effort) 0 and a near zero value of basic derived signal 75 (snore amplitude).
  • the aforesaid state may be accompanied by a marked change in basic derived signal 135 (ballistocardiogram amplitude).
  • the aforesaid state ie coincidence of states 1 , 2 and 3 above
  • Diagnostic signal 87 is indicative of the expected accuracy of the above- mentioned diagnostic signal 85 (obstructive apnea occurrence). This is calculated only if diagnostic signal 85 indicates the occurrence of a said obstructive apnea and typically 5 may be determined from the following states of the above-mentioned basic derived signals: a marked increase in the ratio of basic derived signal 65 (respiratory effort) with respect to basic derived signal 73 (respiratory displacement), plus ⁇ o a low level during the preceding minute of basic derived signal 81 (non- respiratory movements) plus, optionally a marked shift of basic derived signal 71 (zero phase point) during the apparent obstructive apnea 15 plus, optionally a marked shift of basic derived signal 98 (spatial respiratory maximum effort point) during the apparent said obstructive apnea.
  • Diagnostic signal 88 is indicative of the occurrence of a central apnea. This may be determined from the following states of the above-mentioned basic derived signals: reduction towards zero in basic derived signal 73 (respiratory displacement) compared with 5 minute moving average of basic derived signal 73 (respiratory 25 displacement), plus reduction towards zero in basic derived signal 65 (respiratory effort) compared with 5 minute moving average of basic derived signal 65 (respiratory effort), plus 30 near zero value of basic derived signal 75 (snore amplitude), followed after a variable period by increase in basic derived signal 73 (respiratory displacement) compared with 1 minute moving average of basic derived signal 73 (respiratory displacement), plus 35 increase in basic derived signal 65 (respiratory effort) compared with 1 minute moving average of basic derived signal 65 (respiratory effort), or, optionally, immediately followed by a sudden increase in basic derived signal 81 (non-respir
  • Diagnostic signal 89 is indicative of the duration in time of the above- mentioned central apnea. This is calculated only if diagnostic signal 88 indicates the occurrence of a central apnea and may be determined from the length of time of the coincidence of a reduction in basic derived signal 73 (respiratory displacement) compared with 5 minute moving average of basic derived signal 73 (respiratory displacement), a reduction in basic derived signal 65 (respiratory effort) compared with 5 minute moving average of basic derived signal 65 (respiratory effort) and a near zero value of basic derived signal 75 (snore amplitude).
  • Diagnostic signal 90 is indicative of the expected accuracy of the above- mentioned diagnostic signal 88 (central apnea occurrence). This is calculated only if diagnostic signal 88 indicates the occurrence of a central apnea and may be determined from the following states of the above-mentioned basic derived signals: no marked increase in the ratio of basic derived signal 65 (respiratory effort) with respect to basic derived signal 73 (respiratory displacement), plus a low level during the preceding minute of basic derived signal 81 (non- respiratory movements) plus no marked shift of basic derived signal 71 (zero phase point) during the apparent said central apnea.
  • the above-mentioned diagnostic signals 85 (obstructive apnea indication) and
  • central apnea indication may be expressed simultaneously in the case of a mixed apnea, that is, a combination of both types of apnea.
  • Occurrence of Sudden Body Movement Diagnostic signal 91 is indicative of the occurrence of a sudden body movement without a preceding apnea. Typically this would be determined from the following states of the above-mentioned basic derived signals and the above-mentioned diagnostic signals: the absence of diagnostic signal 85 (obstructive apnea occurrence) plus the absence of diagnostic signal 88 (central apnea occurrence) plus a sudden increase in basic derived signal 81 (non-respiratory movements). Degree of Obstructive Breathing
  • Diagnostic signal 92 is indicative of the degree of obstructive breathing present. Typically this may be calculated from the following states of the above- mentioned basic derived signals: the ratio of basic derived signal 65 (respiratory effort) to basic derived signal 73 (respiratory displacement) averaged over a 1 minute period or the ratio of basic derived signal 65 (respiratory effort) to basic derived signal 73 (respiratory displacement) averaged over the previous breath plus, optionally the value of basic derived signal 75 (snore amplitude), plus, optionally the inverse value of basic derived signal 77 (snore harmonic purity) Diagnostic signals 85 through 92 are subsequently: a) stored to computer disk 107, and/or b) output graphically to display means 106 in one of several forms, for example as a condensed report of the night's study (as shown in Fig. 19), and/or c) output in alphanumeric coded form to physiologic channel output means 110 for subsequent recording and display in association with other electrophysio
  • An objective measure of laboured breathing can be derived from two of the abovementioned basic processing means.
  • the aforementioned Average Respiratory Phase Effort and Maximum Respiratory Phase Effort signals are processed using the aforementioned indications of respiratory phase change which delineate the temporal boundaries of inspiration and expiration, to derive two signals, respectively the Average Effort Ratio and the Maximum Effort Ratio.
  • the Average Effort Ratio is determined by dividing the Average Respiratory Phase Effort for the respiratory phase just ended by that determined for the previous phase.
  • the Maximum Effort Ratio is determined by dividing the values of Maximum Respiratory Phase Effort for successive phases. For non-laboured breathing, the values of the Average Respiratory Phase Effort and Maximum Respiratory Phase Effort for inspiration and expiration are approximately equal for inspiration and expiration, giving Effort Ratios of approximately unity. If, however, the execution of one phase of respiration, for example inspiration, becomes significantly laboured relative to the other phase, then the Effort Ratios will move away from unity by a factor of two or more.
  • the procedures used to quantify 'laboured' breathing described above may be applied to determine the amount of snoring present, in which case the bandpass frequencies of the effort filters described above are approximately 10 Hz and 100 Hz.
  • the ratios so determined are termed the Average Snore Ratio and the Maximum Snore Ratio.
  • the difference in the speed at which a subject changes from inspiration to expiration is compared with vice versa to indicate which of these changes has occurred.
  • the time taken for the past time correlation value to fall from an Upper Threshold (not shown) to a Lower Threshold (not shown) for the most recent fall of the said correlation is compared to the time taken for the previous transition in correlation between the same thresholds (Curve 'B' in Fig. 18b). if the latter transition is slower then the current phase is inspiration, if faster, expiration.
  • Particular subgroups of respiratory ailments are characterised by the occurrence of laboured breathing in a particular phase of respiration.
  • sufferers from Obstructive Sleep Apnea and most other upper respiratory tract disfunctions will work harder on inspiration than expiration.
  • the system compares the Average Effort Ratio and/or the Maximum Effort Ratios with threshold values typically of 1.2 and 0.8. If the Ratios exceed the upper threshold then the last phase was an inspiration, if it is less than the lower threshold, then an expiration.
  • the abovementioned Average Snore Ratio and Maximum Snore Ratios may also be used to classify the respiratory phase.
  • the system makes use of the fact that in most patient groups inspiration and attempted inspiration is associated with expansion of the thorax, by processing the signals from a ⁇ o selected range of sensor strips from the top location (normally adjacent to the patient's neck or scapulae) down to the approximate level of the patient's waist.
  • the signals from the said range of strips is summed and that sum compared with zero.
  • the transition of the said sum from a negative value to a positive one is an indication of inspiration while the reverse i s transition, from positive to negative, is indicative of expiration.
  • This embodiment takes as input the output from a selection of the abovementioned methods and derives a weighted vote as to which phase 25 is present. If the said vote is above the Inspiratory Vote Threshold then an inspiration is indicated, if below the Expiratory Vote Threshold, then an expiration. If the said vote lays within the two thresholds then an Uncertain Phase is indicated.
  • the breathing classification can now be used to detect similar and dissimilar breaths in the diagnostic processing means 84.
  • a sample breath pattern can be computed in the abovedescribed manner.
  • the current breath pattern can be sampled for comparison with the said stored breath pattern
  • One instance of a comparison method is to compare the magnitude of each of the sensor channels in the two patterns, computing a Breath Pattern Match Index which is large for a good match and small for a bad match. This can be effected by performing a multiplication between the normalised magnitudes of corresponding sensor signal vectors in the two patterns and summing the result:
  • Another instance of a comparison method is to compare the amplitude and phase of each of the sensors in the two patterns, computing a Breath Pattern Match Index which is large for a good match and small for a bad match. This can be effected by performing a scalar multiplication between corresponding sensor vectors in the two patterns and summing the result:
  • the current breath pattern is compared with immediate or near- immediate past patterns.
  • One example relates to the signal 81 , representing a measure of non-respiratory movements of the patient, being used as a trigger to the breath comparison.
  • the breath pattern before the movement is compared with a breath pattern from, say, 30 seconds before the movement, thereby allowing the detection of a transition from relatively unobstructed breathing, the eventual result of which was the movement arousal.
  • a signal 93 is output. This signal represents the fact of a shift in pattern immediately before the arousal. In this way it is possible to detect the true arousals due to obstructed breathing or flow limitation, for example.
  • the diagnostic signals 85 through 92, and signals representative of the degree of laboured breathing, the degree of snoring and the classification of respiratory phase can be used as part of a closed loop to determine and/or control the pressure setting of a Continuous Positive Airway Pressure (CPAP) treatment machine comprising a flow generator 128 that treats obstructive sleep apnea via air delivery tube and mask assembly 129.
  • CPAP Continuous Positive Airway Pressure
  • a monitoring system 101 measures the respiratory parameters of the patient 1 in the manner described above and, if obstructive respiratory events are observed, transmits a control signal 130 to the CPAP flow generator 128 via CPAP control means 113.
  • One example of an obstructive event is the output signal 93 resulting from the Breath Pattern Comparison.
  • the control signal 130 increases the treatment pressure if obstructive events are observed and slowly decreases it in the absence of obstructive events.
  • the aforesaid process of pressure control may be used either as a means of continuously controlling the treatment pressure during the time the patient sleeps or to determine, over the course of one or more nights, the optimum static treatment pressure to which the CPAP flow generator 128 should be set for continuing, subsequent treatment in the absence of the monitoring system 101.
  • monitoring system 101 is attached to the CPAP flow generator 128 for a diagnostic period comprising a small number of initial nights, typically between one and five, wherein it controls the pressure of the said CPAP flow generator 128 to limit the number of respiratory obstructive events experienced by the patient.
  • the CPAP flow generator 128 is left programmed with the pressure determined by monitoring system 101 as the optimum for the limitation of the respiratory obstructions.
  • the monitoring system 101 is disconnected from the CPAP machine leaving the said machine programmed to the optimum treatment pressure determined.
  • monitoring system 101 follows a set protocol for determining the pressure setting or settings for the CPAP treatment machine.
  • This protocol is open to modification by clinical staff but typically determines the range of pressures needed to reduce the number of apneas and hypopneas to below a preset number, typically 6 per hour.
  • the protocol makes use of above-mentioned diagnostic accuracy indicators 87 and 90 plus other means to reduce the effect of artefacts causing too high a pressure determination.
  • the protocol may advantageously take into consideration diagnostic measurements made over several nights.
  • the above-mentioned diagnostic period can be repeated, for example annually, to maintain the setting of the CPAP flow generator 128 near its optimum.
  • monitoring system 101 produces a report at the end of said diagnostic phase that indicates the main physiological observations of the study and which may assist in the choice of CPAP treatment machine type. Additionally, the report highlights the occurrence of anomalous respiratory behaviour, including the occurrence of central apneas, that may contraindicate conventional CPAP treatment.
  • VCRs time synchronised video cassette recorders
  • the invention uses the monitoring system 101 to trigger a video camera that is aimed at the patient so that only the frames immediately preceding and succeeding a notable respiratory event are recorded as a video clip.
  • the aforesaid video clip may be digitised and stored on computer disk 107 with the rest of the physiological information.
  • the main recording medium 107 may be the tape of a conventional VCR, the video channel of which records the patient video clips, the audio channel of which records, in digitally modulated form, such as the output of a line modem, a combination of the above- mentioned digitised signals 60, the above-mentioned basic derived signals 64 et seq. and the above-mentioned diagnostic signals 85 et seq.
  • the recording of snore is also a factor in the monitoring of partially obstructed breathing and there remain subtleties of sound that need the human ear to determine.
  • the option exists for listening to the snore component of the originally recorded signals, processed for snore detection using the high pass filter as in the derivation of basic derived signal 75 can optionally be played out in real time via sound output means 114, typically a multimedia " SoundBlaster" card, connected to computing means 104.
  • sound output means 114 typically a multimedia " SoundBlaster" card
  • polygraph input means 110 is provided as a means of integrating the system described above with existing clinical recording systems in both sleep laboratories and other clinical environments such as intensive therapy and coronary care units.
  • the polygraph input means 110 provides a method of outputting from the system indications of the states of diagnostic signals 85-92 in a form that can be input to the recording system of, for example, a polygraph (shown in Fig. 23) via a physiological input channel of the polygraph.
  • the advantage of the polygraph input means 110 is that no specialist interface need be available in the polygraph, only an unused analogue physiological input channel such as that used for an ECG or EMG,
  • polygraph input means 110 comprises computer interface means 116 which is connected to an at least 4 bit wide parallel digital output port of ⁇ o computing means 104, isolation means 117 which electrically isolates the parallel digital outputs of computing means 104 from the isolated digital outputs 118.
  • the isolated digital outputs 118 are connected to an isolated digital to analog converter (DAC) 119, the output 120 of which is attenuated by attenuator 121 and presented as an input 122 to a physiological signal input channel of a polygraph .
  • DAC digital to analog converter
  • the polygraph input means 110 thus allows the input to a polygraph of a series of analog voltage steps, the amplitude of the steps being determined by the digital input applied to the isolated DAC 119.
  • the output voltage of the polygraph input means 110 may be caused to trace letters and
  • Fig. 22a shows a graph of voltage against time of the 7 by 5 element matrix 123 that is used to construct one of the alphanumeric characters 127.
  • Baseline 124 is the voltage output when the system is idling. Fast transitions 125 between dots 126 on the aforesaid matrix are almost invisible on the review screen, leaving the dots, for which the voltage
  • Fig. 22b indicates the tracing necessary to display the letter "A" .
  • the aforesaid facility enables computing means 104 to output alphanumeric forms of a selection of diagnostic variables 85-92 to the polygraph, shown in Fig. 23, allowing simultaneous comparison on the polygraph display 131 of the conventional physiological signals 132 being recorded and the diagnoses 133 of the system described above.
  • the effectiveness of the treatment may be assessed by determining the residual number of obstructive apneas that occur using the above-mentioned techniques.
  • the aforesaid assessment of effectiveness may also be used to verify that the patient has, in fact, been submitting to treatment by the CPAP flow generator or has been avoiding the same.
  • System 101 can, therefore, also be used as a compliance monitor for CPAP treatment.
  • a die cut part 5 is seen in Fig 24 where a number of sensor strips 5 are cut out from a single sheet of PVDF from which is also formed tail strip 5A.
  • Separate conductive tracks 17 and 17' on each face of each of the sensor strips 35(Fig 25) are formed by selective etching or printing at the metallisation layers of the tail strip, 5A to conduct the sensor signals to bus connector 42A.
  • the PVDF film material is normally only producible in strips that can be many metres long but which have a restricted width that may be too narrow to allow the manufacture of a large one -part multistrip assembly 9 in the form visualised in Fig 24.
  • the one-piece form thus displayed is advantageous from a manufacturing point of view - whereby all the strips 5 are part of a single, die cut sheet and, further, in which the electrical connections from each strip 5 may be conducted from the strip via metallisation on integral tailstrip 5 A.
  • Fig. 26 shows a further embodiment, which involves the cutting of a relatively narrow (typically 6 cm wide) sheet of PVDF 11 with a pattern illustrated in Fig 26a, consisting of a number (typically between 4 and 15) of staggered parallel cuts 14 separated by the required width of each sensor strip (typically 1 cm), and of length equal to that required in the aforesaid sensor strips 5, typically 60 cm.
  • the parallel cuts dissect out from the PVDF film, strips 5 whose length is limited only by the length of the said film and not its breadth. Subsequent to the aforesaid dissection, each of the strips 5 is folded into a position 90 degrees from its original orientation at its base 150 via a crease 152 oriented at 45 degrees to the said cuts (Fig 26b).
  • the residual unfolded element of PVDF sheet 10 serves as an integral tail strip 5A which conducts the electrical signals away from the said sensor strips to a remote electrical connector.
  • PVDF sheet 11 may be manufactured with stabilising element 11a (Fig 27a) consisting of an integral portion of the said sheet which folds underneath and is glued to the sheet and to the folded sensor strips 5 (Fig 27b). The said 45 degree creasing of the strips 5 is thus immobilised, thereby removing any tendency for the strips 5 to return elastically to their original orientation.
  • stabilising element 11a Fig 27a
  • Fig. 28 shows in more detail the electrical connections 17 from each sensor strip 5 along tail strip 5A to bus connector 42A. Normally there will be two separate connections 17 and 17' from each of the sensor strips 5, one from each face. In another, simpler configuration, one face of each of the strips 5 is connected in common and that single common connection is conducted to bus connector 42A along with the single connections from the obverse sides of each individual strip (Fig 29a).
  • all or some of the top faces of the said sensor strips may be connected in common and, separately, all the obverse faces may be likewise connected in common, to give just two electrical connections to the assembly (Fig 29b).
  • Such a simplification no longer allows the signal from each of the said sensor strips to be recorded separately, rather the output electrical signal is the sum of all the individual responses.
  • further conductive layers or films may be applied over the entire area of the PVDF film 11 to shield the aforesaid connections from external electrical interference.
  • Figs 30a and 30b show in more detail the design of the conductive metallisation 13 on the top surface (Fig 30a) and conductive metallisation 14 on the obverse (Fig 30b) which collect the strain-generated charge from the strip and conduct it to the bus connector 42 A. Electrical charge is only conducted from the faces of the sensor strips 5 when each opposing face is metallised with conductive layers which overlap. In order to limit the area of sensitivity to that of the strip itself, the opposing metallisation patterns are staggered in the region 15 & 16 of said 45 degree crease and, thereafter, on tail strip 5A. This renders the region of the said crease and the tail strip insensitive to any strains that maybe imposed thereon.
  • the complete movement sensitive mattress may be mounted in an assembly less than 3 mm in thickness, allowing its easy and comfortable location on a range of conventional mattress sizes.
  • the thin movement sensitive mattresses described above can be regarded as a movement-sensitive sheet.
  • Fig. 32a Movement-sensitive mattress or sheet 2' is constructed as described above with sensor strips 5 connected to tail strip 5 A and bus connector 42 A, the assembly thereof being sandwiched between thin neoprene or other suitably waterproof, flexible sheet 6A.
  • the said sheet 6 A is, however, perforated with holes 6B that allow the assembly to "breathe" - that is, to facilitate the diffusion of humidity from the area in contact with the patient to the conventional bedding beneath the said movement sensitive mattress or sheet.
  • the location of the sensor strips 5 are optionally located by web components 6C.
  • the sensor strips 5 may be enclosed by the waterproof envelope 6A only in the immediate vicinity thereof (Fig. 32b). In this configuration gaps 6D between the enclosed sensor strips 5 facilitate the above-mentioned diffusion of humidity away from the subject.
  • Fig. 32c shows an arrangement of six sensors 5' arranged at the edge margin of the mattress 2.
  • Lateral strain elements 162, acting to channel vertical body displacement to the respective sensor 5' are provided.
  • a series of alternating slits 160 can be provided to decouple or isolate adjacent strain elements 162.
  • channelling of the lateral strain to each sensor 5' may be achieved by use of a substrate material (not shown) in which the lateral (left-to-right) stiffness is significantly greater than the longitudinal (head-to-toe) direction.
  • the movement-sensitive mattress or sheet 2' is mounted on a carrier sheet 7' typically made of cotton or an equivalent porous bed sheeting material or net (Fig. 33).
  • the mounting method for the construction may be permanent, whereby movement-sensitive mattress or sheet 2' is permanently bonded to carrier sheet 7' , or removable, whereby movement-sensitive mattress or sheet 2' is attached to carrier sheet 7' by fastenings such as Hadrdashers' press studs or "Velcro"TM hook and loop material.
  • the construction of carrier sheet 7' can, advantageously, follow the form of a conventional "fitted" bedding sheet whereby an elasticated border (not shown) holds the carrier sheet 7' on to a conventional mattress 3.
  • the movement sensitive mattress 2,5 may be replaced, as shown in Fig. 34, by an array of electrode assemblies 205 each assembly being located about a different part of the patient's torso.
  • the assemblies 205 each consist of two electrodes 208, 208' the resistance between which is measured via connections 207, 207' by resistance measuring means 209 shown in Fig. 36.
  • the outputs of measuring means 209 are input to the multichannel Analog to Digital Converter 45 for subsequent processing indentical to that used in the abovementioned PVDF sensor based embodiment.
  • the movement sensitive mattress 2, 5 may be replaced, as shown in Fig. 37, by an array of electrical coil assemblies 210 each assembly being located about a diffeent part of the patient's torso.
  • the said assemblies 210 each consist of a coil of conductive material 211, typicaly made of fine wire, wound typically once round the patient's torso, the inductance of the said coil being measured via connection means 212, 212' by inductance measuring means 213 shown in Fig. 39.
  • the outputs of measuring means 213 again are input to a multichannel Analog to Digitial Converter 45 for subsequent processing identical to that used in the abovementioned PVDF sensor based embodiment.
  • the movement sensitive mattress 2, 5 may be replaced, as shown in Figs. 40 and 41, by an array of sealed tube assemblies 214, partially inflated with liquid or gas located beneath the upper torso of the patient on the surface of the bed or within or underneath the mattress, each said tube being connected to pressure measuring means 216 that measures its internal pressure and produces an electrical output 217.
  • the outputs of measuring means 214 again are input to a multichannel Analog to Digital Converter 45 via interface means 218 for subsequent processing identical to that used in the abovementioned PVDF sensor based embodiment.

Landscapes

  • Health & Medical Sciences (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • Biophysics (AREA)
  • General Health & Medical Sciences (AREA)
  • Veterinary Medicine (AREA)
  • Public Health (AREA)
  • Animal Behavior & Ethology (AREA)
  • Surgery (AREA)
  • Molecular Biology (AREA)
  • Medical Informatics (AREA)
  • Heart & Thoracic Surgery (AREA)
  • Pathology (AREA)
  • Biomedical Technology (AREA)
  • Physiology (AREA)
  • Artificial Intelligence (AREA)
  • Evolutionary Computation (AREA)
  • Signal Processing (AREA)
  • Psychiatry (AREA)
  • Mathematical Physics (AREA)
  • Computer Vision & Pattern Recognition (AREA)
  • Fuzzy Systems (AREA)
  • Pulmonology (AREA)
  • Dentistry (AREA)
  • Oral & Maxillofacial Surgery (AREA)
  • Measurement Of The Respiration, Hearing Ability, Form, And Blood Characteristics Of Living Organisms (AREA)

Abstract

L'invention concerne un système d'analyse de respiration (101) permettant de surveiller une variable respiratoire chez un patient (1). Le système comprend un ensemble de détecteurs (102) adaptés pour venir en contact avec un patient (1), ainsi que des moyens de traitement (104). L'ensemble de capteurs (102) comporte une pluralité de capteurs (5) quasi indépendants, servant à mesurer le mouvement respiratoire en différents emplacements du patient (1), pour générer un ensemble de signaux de mouvement respiratoire indépendants. Les moyens de traitement (104) reçoivent et traitement les signaux de mouvement pour en dériver une classification de respirations individuelle au moyen, pour chaque respiration, de la phase respective et/ou de l'amplitude de chaque signal de capteur de mouvement faisant partie de l'ensemble de signaux relatifs à cette respiration.
PCT/AU2000/000326 1999-04-14 2000-04-17 Detection et classification de modeles de respiration Ceased WO2001078601A1 (fr)

Priority Applications (3)

Application Number Priority Date Filing Date Title
PCT/AU2000/000326 WO2001078601A1 (fr) 2000-04-17 2000-04-17 Detection et classification de modeles de respiration
AU42752/00A AU4275200A (en) 1999-04-14 2000-04-17 Detection and classification of breathing patterns
US10/257,316 US6840907B1 (en) 1999-04-14 2000-04-17 Detection and classification of breathing patterns

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
PCT/AU2000/000326 WO2001078601A1 (fr) 2000-04-17 2000-04-17 Detection et classification de modeles de respiration

Publications (1)

Publication Number Publication Date
WO2001078601A1 true WO2001078601A1 (fr) 2001-10-25

Family

ID=3700795

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/AU2000/000326 Ceased WO2001078601A1 (fr) 1999-04-14 2000-04-17 Detection et classification de modeles de respiration

Country Status (1)

Country Link
WO (1) WO2001078601A1 (fr)

Cited By (11)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2006037184A1 (fr) * 2004-10-06 2006-04-13 Resmed Limited Procede et appareil pour surveillance non invasive de parametres respiratoires lors de troubles respiratoires du sommeil
EP1567055A4 (fr) * 2002-11-25 2008-07-23 Varian Med Sys Tech Inc Procede et systeme de controle de l'activite respiratoire d'un individu
US7652581B2 (en) 2004-02-18 2010-01-26 Hoana Medical, Inc. Method and system for integrating a passive sensor array with a mattress for patient monitoring
US7666151B2 (en) 2002-11-20 2010-02-23 Hoana Medical, Inc. Devices and methods for passive patient monitoring
AU2011203234B2 (en) * 2004-10-06 2013-01-10 Resmed Limited Method and Apparatus for Non-Invasive Monitoring of Respiratory Parameters in Sleep Disordered Breathing
WO2015091582A1 (fr) * 2013-12-19 2015-06-25 Koninklijke Philips N.V. Dispositif de surveillance d'un bébé
WO2016146889A1 (fr) * 2015-03-13 2016-09-22 Emfit Oy Matelas permettant à une personne de se reposer ou de dormir
CN108289620A (zh) * 2015-11-13 2018-07-17 皇家飞利浦有限公司 用于传感器位置引导的设备、系统和方法
JP2018134424A (ja) * 2012-03-01 2018-08-30 ヘルスセンシング株式会社 検出装置
RU201833U1 (ru) * 2020-09-02 2021-01-14 Общество с ограниченной ответственностью "СЛИПО" (ООО "СЛИПО") Устройство регистрации биофизических показателей человека в течение сна
WO2022060240A1 (fr) * 2020-09-16 2022-03-24 Общество с ограниченной ответственностью "СЛИПО" (ООО "СЛИПО") Unité d'enregistrement et de transmission de données

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4777962A (en) * 1986-05-09 1988-10-18 Respitrace Corporation Method and apparatus for distinguishing central obstructive and mixed apneas by external monitoring devices which measure rib cage and abdominal compartmental excursions during respiration
US5134281A (en) * 1990-01-31 1992-07-28 E.L. Bryenton & Associates Inc. Microbend optic sensor with fiber being sewn thereto in a sinuously looped disposition
GB2261290A (en) * 1991-11-07 1993-05-12 Alan Remy Magill Physiological monitoring
GB2319851A (en) * 1996-11-29 1998-06-03 Adaptivity Devices Ltd Monitoring the physiological condition of a patient
WO1998052467A1 (fr) * 1997-05-16 1998-11-26 Resmed Limited Systemes d'analyse respiratoire

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4777962A (en) * 1986-05-09 1988-10-18 Respitrace Corporation Method and apparatus for distinguishing central obstructive and mixed apneas by external monitoring devices which measure rib cage and abdominal compartmental excursions during respiration
US5134281A (en) * 1990-01-31 1992-07-28 E.L. Bryenton & Associates Inc. Microbend optic sensor with fiber being sewn thereto in a sinuously looped disposition
GB2261290A (en) * 1991-11-07 1993-05-12 Alan Remy Magill Physiological monitoring
GB2319851A (en) * 1996-11-29 1998-06-03 Adaptivity Devices Ltd Monitoring the physiological condition of a patient
WO1998052467A1 (fr) * 1997-05-16 1998-11-26 Resmed Limited Systemes d'analyse respiratoire

Cited By (15)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US7666151B2 (en) 2002-11-20 2010-02-23 Hoana Medical, Inc. Devices and methods for passive patient monitoring
EP1567055A4 (fr) * 2002-11-25 2008-07-23 Varian Med Sys Tech Inc Procede et systeme de controle de l'activite respiratoire d'un individu
US7652581B2 (en) 2004-02-18 2010-01-26 Hoana Medical, Inc. Method and system for integrating a passive sensor array with a mattress for patient monitoring
AU2005291858B2 (en) * 2004-10-06 2011-07-28 Resmed Limited Method and apparatus for non-invasive monitoring of respiratory parameters in sleep disordered breathing
AU2011203234B2 (en) * 2004-10-06 2013-01-10 Resmed Limited Method and Apparatus for Non-Invasive Monitoring of Respiratory Parameters in Sleep Disordered Breathing
WO2006037184A1 (fr) * 2004-10-06 2006-04-13 Resmed Limited Procede et appareil pour surveillance non invasive de parametres respiratoires lors de troubles respiratoires du sommeil
US9220856B2 (en) 2004-10-06 2015-12-29 Resmed Limited Method and apparatus for non-invasive monitoring of respiratory parameters in sleep disordered breathing
US10398862B2 (en) 2004-10-06 2019-09-03 ResMed Pty Ltd Method and apparatus for non-invasive monitoring of respiratory parameters in sleep disordered breathing
JP2018134424A (ja) * 2012-03-01 2018-08-30 ヘルスセンシング株式会社 検出装置
WO2015091582A1 (fr) * 2013-12-19 2015-06-25 Koninklijke Philips N.V. Dispositif de surveillance d'un bébé
CN106028915A (zh) * 2013-12-19 2016-10-12 皇家飞利浦有限公司 婴儿监测装置
WO2016146889A1 (fr) * 2015-03-13 2016-09-22 Emfit Oy Matelas permettant à une personne de se reposer ou de dormir
CN108289620A (zh) * 2015-11-13 2018-07-17 皇家飞利浦有限公司 用于传感器位置引导的设备、系统和方法
RU201833U1 (ru) * 2020-09-02 2021-01-14 Общество с ограниченной ответственностью "СЛИПО" (ООО "СЛИПО") Устройство регистрации биофизических показателей человека в течение сна
WO2022060240A1 (fr) * 2020-09-16 2022-03-24 Общество с ограниченной ответственностью "СЛИПО" (ООО "СЛИПО") Unité d'enregistrement et de transmission de données

Similar Documents

Publication Publication Date Title
US6840907B1 (en) Detection and classification of breathing patterns
US6547743B2 (en) Respiratory-analysis systems
US20240298910A1 (en) Acoustic physiological monitoring system
US5964720A (en) Method and system for monitoring the physiological condition of a patient
US6363270B1 (en) Monitoring the occurrence of apneic and hypopneic arousals
WO2006023940A2 (fr) Systeme, logiciel et procede de detection de troubles respiratoires au cours du sommeil a l'aide d'un electrocardiogramme
JP6599723B2 (ja) 生体情報取得装置及び信号処理方法
JP7177443B2 (ja) 生体振動信号検出装置
JP2013009980A (ja) 呼吸数又は心拍数測定装置及び測定システム
WO2008135985A1 (fr) Suivi, prévision et traitement d'épisodes cliniques
WO2003013355A1 (fr) Detection d'apnees centrales
CA2262236C (fr) Phonospirometrie pour la surveillance non invasive de la respiration
WO2001078601A1 (fr) Detection et classification de modeles de respiration
JP2017169647A (ja) 生体信号測定装置及び生体信号測定方法
WO2007094464A1 (fr) Instrument de mesure de la fonction cardio-pulmonaire
KR20190052626A (ko) 호흡 센싱 디바이스 및 이를 포함하는 호흡 모니터링 시스템
JP7260083B2 (ja) 振動センサ、生体情報検出装置及び寝具
CA3100475C (fr) Appareil et procede de surveillance d'un patient pendant son sommeil
AU742291B2 (en) Respiratory-analysis systems
JP2005160650A (ja) 無呼吸症候群判定装置
AU4275200A (en) Detection and classification of breathing patterns
Manecke Jr et al. Auscultation revisited: The waveform and spectral characteristics of breath sounds during general anesthesia
Nakasho et al. Implementation of a vital signs monitoring system in combination with a bed-leaving detection system
JPH08317909A (ja) 就寝状態判定装置
Karhu Piezoelectric sensors for measuring biosignals

Legal Events

Date Code Title Description
AK Designated states

Kind code of ref document: A1

Designated state(s): AE AG AL AM AT AU AZ BA BB BG BR BY CA CH CN CR CU CZ DE DK DM DZ EE ES FI GB GD GE GH GM HR HU ID IL IN IS JP KE KG KP KR KZ LC LK LR LS LT LU LV MA MD MG MK MN MW MX NO NZ PL PT RO RU SD SE SG SI SK SL TJ TM TR TT TZ UA UG US UZ VN YU ZA ZW

AL Designated countries for regional patents

Kind code of ref document: A1

Designated state(s): GH GM KE LS MW SD SL SZ TZ UG ZW AM AZ BY KG KZ MD RU TJ TM AT BE CH CY DE DK ES FI FR GB GR IE IT LU MC NL PT SE BF BJ CF CG CI CM GA GN GW ML MR NE SN TD TG

DFPE Request for preliminary examination filed prior to expiration of 19th month from priority date (pct application filed before 20040101)
121 Ep: the epo has been informed by wipo that ep was designated in this application
WWE Wipo information: entry into national phase

Ref document number: 10257316

Country of ref document: US

122 Ep: pct application non-entry in european phase
NENP Non-entry into the national phase

Ref country code: JP