WO2012059768A1 - Appareil et procédés de prélèvement d'haleine - Google Patents

Appareil et procédés de prélèvement d'haleine Download PDF

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Publication number
WO2012059768A1
WO2012059768A1 PCT/GB2011/052145 GB2011052145W WO2012059768A1 WO 2012059768 A1 WO2012059768 A1 WO 2012059768A1 GB 2011052145 W GB2011052145 W GB 2011052145W WO 2012059768 A1 WO2012059768 A1 WO 2012059768A1
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WO
WIPO (PCT)
Prior art keywords
breath
sampling
sampling device
conduit
received
Prior art date
Application number
PCT/GB2011/052145
Other languages
English (en)
Inventor
Maria Sanchez Basanta
Stephen James Fowler
Original Assignee
The University Of Manchester
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 The University Of Manchester filed Critical The University Of Manchester
Publication of WO2012059768A1 publication Critical patent/WO2012059768A1/fr

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Classifications

    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
    • A61B5/00—Measuring for diagnostic purposes; Identification of persons
    • A61B5/08—Detecting, measuring or recording devices for evaluating the respiratory organs
    • A61B5/097—Devices for facilitating collection of breath or for directing breath into or through measuring devices
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
    • A61B5/00—Measuring for diagnostic purposes; Identification of persons
    • A61B5/03—Detecting, measuring or recording fluid pressure within the body other than blood pressure, e.g. cerebral pressure; Measuring pressure in body tissues or organs
    • 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
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N1/00—Sampling; Preparing specimens for investigation
    • G01N1/02—Devices for withdrawing samples
    • G01N1/22—Devices for withdrawing samples in the gaseous state
    • G01N1/2202—Devices for withdrawing samples in the gaseous state involving separation of sample components during sampling
    • G01N1/2214—Devices for withdrawing samples in the gaseous state involving separation of sample components during sampling by sorption

Definitions

  • Breath analysis is sometimes useful in the diagnosis of medical conditions, and may also be useful in preventative, predictive and personalised medicine.
  • Breath analysis involves the determination of one or more components of a patient's exhaled breath.
  • breath analysis may be useful for diagnosis of conditions associated with gastroenterology and chronic obstructive pulmonary disease (COPD).
  • COPD chronic obstructive pulmonary disease
  • Breath analysis may involve the measurement of gasses such as C0 2 , CH 4 and H 2 , and also volatile organic compounds (VOCs).
  • VOCs volatile organic compounds
  • a breath sampling system comprising breath receiving means for receiving breath; a sensor for sensing a characteristic of the received breath and outputting an indicative signal; a sampling device for sampling the breath, wherein the sampling device is arranged such that received breath has a predetermined transit time between the sensor and the sampling device; a control unit for receiving the indicative signal and controlling the sampling device to receive a predetermined portion of the received breath in response thereto.
  • the control unit may be arranged to selectively direct the predetermined portion of the received breath to the sampling device in response to the indicative signal.
  • the control unit may be arranged to determine when the characteristic of the received breath meets a predetermined threshold and to direct the received breath to the sampling device following a predetermined delay.
  • the predetermined delay maybe substantially equal to the transit time.
  • the control unit may be arranged to control the sampling device to receive the predetermined portion of breath having one or more characteristics previously sensed by the sensor at a time substantially up to the transit time ago, and to direct received breath not having the one or more characteristics away from the sampling device.
  • the control unit may be arranged to selectively redirect a predetermined portion of the received breath away from the sampling device, wherein the predetermined portion may be breath previously sensed by the sensing device.
  • the predetermined portion may be breath previously sensed by the sensor at a time up the transmit time.
  • the control unit may be arranged to selectively redirect breath away from the sampling device in response to the indicative signal, wherein the control unit is arranged to determine a portion of breath in transit between the sensor and the sampling device having an associated characteristic and to control the sampling device such that the portion is directed away from the sampling device.
  • the sampling device may be arranged in a sampling conduit and the control unit is arranged to selectively enable a flow of the patient's breath through the sampling conduit.
  • the system may comprise a bypass conduit, wherein the control unit is arranged to selectively control a flow of the patient's breath through the bypass conduit to bypass the sampling device.
  • the bypass conduit may comprise a restrictor for restricting airflow there -through to substantially that of the sampling device.
  • the system may comprise a valve means arranged to selectively direct the patient's breath to the sampling device in response to a valve signal from the control unit.
  • the control unit may be arranged to determine one or more characteristics of a steady breathing pattern of the patient.
  • the predetermined portion of the received breath may be determined by the sampling device based on the indicative signal.
  • the predetermined portion may be an alveolar portion of the patient's breath.
  • the predetermined portion may be a portion of the patient's breath following the indicative signal meeting a threshold.
  • the predetermined portion may be a portion of the patient's breath between the indicative signal meeting a threshold and ceasing to meet the threshold, without a portion of the breath in transit between the sensor and the sampling device.
  • the sensor may be arranged to sense a pressure and/or predetermined gas content of the patient's breath.
  • the predetermined portion of breath exhaled may be receivable by the sampling device at a time t2, whereas the sensor is arranged to sense a characteristic of breath exhaled at a time tl, wherein t2 is later than tl .
  • t2 may be the predetermined transit time later than tl .
  • the control unit may control the sampling device to begin or end sampling of breath exhaled at a time between tl and t2.
  • this allows accurate control over the portion of breath sampled by the sampling device.
  • a method of sampling a predetermined portion of received breath comprising receiving, from a sensing device, a signal indicative of a characteristic of received breath; controlling a sampling device to selectively receive the predetermined portion of the received breath according to the signal, wherein the sampling device is arranged such that breath has a predetermined transit time between the sensing device and the sampling device.
  • the controlling may include selectively directing the predetermined portion of the received breath to the sampling device according to the signal.
  • the selectively directing may include determining a portion of the breath in transit between the sensing device and the sampling device having an associated characteristic and controlling the sampling device to receive the predetermined portion.
  • the method may comprise receiving, from the sensing device, a signal indicative of the received breath having a predetermined characteristic, and controlling the sampling device to receive the breath following a predetermined delay.
  • the predetermined delay may be substantially equal to the transit time.
  • the selectively directing may include determining a portion of the breath in transit between the sensing device and the sampling device having an associated characteristic not meeting a threshold and directing breath away from the sampling device prior to the portion.
  • the method may comprise directing received breath through a restrictor device when not directed to the sampling device.
  • a computer program which, when executed by a computer, performs a method of sampling a predetermined portion of received breath, comprising receiving, from a sensing device, a signal indicative of a characteristic of received breath; controlling a sampling device to selectively receive the predetermined portion of the received breath according to the signal, wherein the sampling device is arranged such that breath has a predetermined transit time between the sensing device and the sampling device.
  • the computer program may be stored on a computer-readable medium.
  • Figure 1 shows an illustration of a system according to an embodiment of the invention
  • Figure 2 illustrates a method according to an embodiment of the invention
  • Figure 3 illustrates an example of a signal indicative of a characteristic of a patient's breath output by a sensor in an embodiment of the invention
  • Figure 4 illustrates a differentiated signal indicative of a characteristic of a patient's breath according to an embodiment of the invention
  • Figure 5 illustrates a system according to a further embodiment of the invention
  • Figure 6 shows an illustration of a signal processing system according to an embodiment of the invention.
  • Figure 7 illustrates a system according to a still further embodiment of the invention.
  • FIG. 1 illustrates a breath sampling system 100 according to a first embodiment of the invention.
  • the system 100 comprises means for isolating air provided to and exhaled from a patient.
  • this means is a mask 110 for attaching to the patient's face.
  • the patient is understood to be the person whose breath will be sampled by the system 100.
  • a suitable mask 110 is a vented mask available from ResMed Corp, California, USA, although it will be realised that other vented and unvented masks may be used.
  • the mask 110 is arranged to seal around the patient's mouth and nose, such that substantially all air is inhaled out of and exhaled into the mask 110 by the patient.
  • air within the mask 110 In the case of using a vented mask, some air within the mask 110, such as air exhaled into the mask 110, escapes from the vent(s) of the mask 110. However, due to a positive air pressure being maintained within the mask 110, as will be explained, operation of embodiments of the invention is unaffected. In other embodiments, air may be communicated to and received from the patient via an airway tube i.e. tracheal intubation. Air is provided to the mask 110 from an air source 120. In some embodiments the air source 120 is a pump 120 which pumps room air into the mask 110 to maintain a positive air pressure in the mask 110.
  • embodiments of the invention may include a filter 125 to filter air provided to the mask 110.
  • the filter 125 may be arranged in an air supply line 121 from the pump 120 to the mask 110, may be integral with the pump 120 or may be arranged in an air inlet port of the mask 110.
  • a suitable filter may be an AX (organic gasses/vapours below 65 °C) filter obtained from 3M (RTM), although filters from other suppliers may also be used.
  • the air source 120 is a mains air connection, wherein breathable air is provided from a supply such as a compressed air container i.e. air storage tank or compressor via an outlet such as a wall-mounted outlet.
  • Air is provided to the mask 110 from the air source 120 sufficient to allow normal breathing by the patient during breath sampling by embodiments of the present invention.
  • One or more pressure sensors 130 may be arranged to measure the pressure of the patient's air supply i.e. air provided to and exhaled by the patient.
  • the pressure sensor 130 is connected to the mask 110 to measure air pressure within the mask 110.
  • the pressure sensor 130 measures variations in air pressure caused by the patient's breathing i.e. a decrease in pressure within the mask 110 caused by the patient inhaling air from the mask 110 and the increase in pressure caused by the patient exhaling air into the mask 110.
  • the pressure sensor 130 may be connected directly to the mask 110 or may be connected to the mask 110 via a length of tubing 131. However, it will be realised that there is substantially no air flow via the pressure sensor 130 such that the pressure sensor measures the air pressure within the mask 110 substantially instantaneously.
  • a suitable pressure sensor 130 is a Honeywell (RTM) 40pc series pressure sensor, although it will be realised that other pressure sensors may be used.
  • the pressure sensor 130 is arranged to output an electrical air pressure signal 132 indicative of the air pressure within the mask 110 to a control unit 140.
  • a plurality of pressure sensors may be used.
  • a first pressure may be arranged to measure air pressure within the mask 110 whilst a second pressure sensor may be arranged to measure an air pressure of the air source 120 for differential air pressure measurement.
  • the air source 120 pressure may be subtracted from the mask 110 pressure to determine an air pressure exerted by the patient breathing.
  • a differential pressure transducer may be arranged to measure and to output a signal indicative of the differential air pressure between the mask 110 and the air source 120.
  • At least some air exhaled by the patient is directed via a sampling conduit 145.
  • air is drawn from the mask 110 though the sampling conduit 145 by a sample pump 180.
  • the sampling conduit 145 includes two or more branches 146, 147 wherein exhaled air is selectively directed through each branch such that a predetermined portion of the patient's breath is drawn through each branch.
  • the sampling conduit 145 comprises two branches.
  • a restrictor branch 146 comprises a restrictor 150 for restricting the flow of air through the restrictor branch to the sample pump 180.
  • a sampling branch 147 comprises a sampling device 160.
  • Air is selectively drawn through the restrictor 146 or sampling branches 147 of the sampling conduit 145 by a three-way valve 170.
  • the valve 170 is controlled by the control unit 140 to draw exhaled air through the restrictor 146 or sampling 147 branches, respectively.
  • the valve 170 selectively connects either the restrictor 146 or sampling 147 branch of the sampling conduit 145 to the sample pump 180 in response to a valve control signal 171 output by the control unit 140.
  • the restrictor 150 may be provided in the restrictor branch 146 to regulate the flow rate of air through the restrictor branch 146 to approximately equal that of the sampling branch 147 via the sampling device 160.
  • the restrictor 150 is arranged to balance a load on the sampling pump 180 between the restrictor and sampling branches 146, 147.
  • the restrictor 150 may, in some embodiments, be a second sampling device 150, although in other embodiments the restrictor 150 may be any device which restricts the flow of air there-through to a predetermined rate.
  • the restrictor or secondary sampling device 150 may be used as a reference to the sampling device 160 for comparison against samples taken from the predetermined portion of breath.
  • the sampling device 160 is arranged for off-line sampling of the exhaled breath.
  • the sampling device 160 is arranged to capture components of the predetermined portion of the patient's breath, such as volatiles in the exhaled air from the patient. The volatiles may be later analysed by a suitable technique.
  • the sampling device 160 is thermal desorption device. The thermal desorption device captures constituents of the patient's breath which may be later removed for analysis from the sampling device 160 by thermal desorption.
  • a suitable sampling device is a sample tube available from Markes International Limited, although it will be realised that other suppliers are available.
  • the sampling device may be formed by a stainless steel tube, having dimensions 3,5"(98mm) long x l/4"(6.4mm) outside diameter (O.D.) x 5mm (internal diameter (I.D.), although it will be realised that other dimension tubes may be used. Tubes are packed by mass (or bed length equivalent) to a tolerance of ⁇ 2.5%. A wide variety of sorbent types may be used depending on the application i.e. which components of breath it is desired to sample.
  • the tube is packed with two beds: a porous polymer, Tenax TA and a bed of Graphitised carbon black, Carbotrap mesh 20/40
  • Tenax TA is a weak sorbent, volatility range coverage n-C7 to n-C30.
  • Carbotrap 20/40 is a weak/medium sorbent, volatility range coverage nC5/6 to n-C14. It will be realised that other sampling materials may be used.
  • the sampling device 160 is arranged for on-line analysis of the exhaled breath.
  • the sampling device 160 is arranged to analyse the exhaled breath and to output a signal indicative of, for example, the volatiles present in the exhaled breath.
  • the analysis may be real-time or a suitable analysis period may be allowed between capture of the volatiles and output of the signal.
  • On-line sampling of the breath may be based upon infra-red spectrophotometry or infra-red spectroscopy, although it will be realised that other sampling techniques may be used.
  • the sampling device 160 is arranged in the sampling conduit 147 to be a predetermined distance from the patient.
  • the sampling device 160 is arranged the predetermined distance from the mask 110.
  • predetermined distance includes the length of the sample conduit 145 and the portion of the sampling branch 147 prior to (upstream of) the sampling device 160.
  • the predetermined distance is provided to allow a predetermined volume of exhaled air to be contained in the sampling conduit 145 and sampling branch 147 between the mask 110 and the sampling device 160.
  • the predetermined distance provides a known transit time for exhaled breath between the mask 110 and the sampling device 160.
  • the arrangement of the sampling device 160 distal from the mask 110 allows accurate analysis of the predetermined portion of the exhaled breath, as will be explained.
  • the sample pump 180 is arranged to draw exhaled air at a predetermined rate through the sample conduit 145 and the selected one of the restrictor branch 146 and sampling branch 147.
  • the predetermined rate may be quantified as, for example, a rate of Y ml/minute.
  • a time delay or transit time of exhaled air between the mask and the sampling device 160 can be determined according to the formula: ⁇ length SC C
  • ⁇ delay is the time delay or transit time of air between the mask 1 10 and the sampling device 160
  • SCi engt h is the length of the sampling conduit 145 (including sampling branch 147) between the mask 1 10 and sampling device 160
  • SC csa is the cross sectional area of the sampling conduit 145
  • F rate is the flow rate of air through the sampling conduit 145.
  • the delay or transit time of the exhaled air is calculated.
  • the sampling conduit 145 has an internal diameter of 1.5875mm (1/16 inch) and a flow rate of lL/minute the time delay or transit time is 59.38 ms.
  • the control unit 140 is arranged to control the operation of the valve 170 to direct only the predetermined portion of the exhaled breath to the sampling device 160, based on the air pressure in the mask 1 10 and the predetermined transit time of air between the mask 1 10 and sampling device 160.
  • the control unit 140 may be arranged to control the valve 170 to direct breath to the sampling device 160 at a time corresponding to the sensed characteristic in addition to the delay time.
  • the valve 170 may be controlled to divert breath to the sampling device at a time after Tdeky i.e. at a point in time at which the breath having the sensed characteristic will have moved through the sampling conduit 145 to the sensing device.
  • the control unit 140 is arranged to control the valve to direct breath toward the sampling device 160 a predetermined time period after the time at which the characteristic is sensed i.e.
  • T notsamp i ed is a time delay to allow an undesired portion of breath for sampling to be exhaled and T delay allows the breath portioned desired for sampling to transit to the sample tube from the mask 110.
  • T notsa mpied may be determined as a percentage of the patient's average breath length or as a fixed value, such a time period in seconds, for all patients.
  • valve 170 may be controlled by the control unit 140 to end sampling of breath at a preceding point up to the transit time e.g. to end sampling with a portion of breath exhaled 40ms ago, when the pressure of exhaled breath had not begun to fall.
  • a method 200 of operating the system 100 will now be described with reference to Figure 2.
  • the method comprises a step 210 in which a positive airway pressure is established.
  • the positive pressure is established by air being provided by the air source 120 to the mask 110 and the positive pressure is established in the mask 110 to allow the patient to breathe normally.
  • a breathing pattern of the patient is established.
  • the control unit 140 includes a timer set to a predetermined time such as 5 or 10 minutes, although other time values may be used, which counts down from the patient's breathing being detected by the pressure sensor 130 i.e. detecting a variation in pressure within the mask 110.
  • an operator may provide an input to the control unit 140, such as by activation of a button, to indicate that the patient has established a generally stable breathing pattern.
  • the control unit 140 may wait a predetermined number of breath cycles, such as 15 although other numbers may be used, before allowing sampling of the patient's breath to begin.
  • the control unit 140 may determine when a steady breathing pattern has been established based on the pressure within the mask 110 indicated by the pressure sensor 130 signal 131. The control unit 140 may determine that steady breathing of the patient has been established according to, for example, a time duration of each breath.
  • the control unit 140 may determine that steady breathing has been established.
  • the control unit 140 may determine, either after the predetermined period of stabilisation time or upon steady breathing of the patient being determined, specific breath pattern information of the specific patient.
  • the specific breath pattern information may include a length of breathing cycle and length of the predetermined portion of the patient's breath i.e. the length of alveolar breathing.
  • the control unit 140 may be determined by the control unit 140 that the patient's breathing pattern has a tidal breath of around 500 ml of which approximately 150ml (40%) is dead space breath and 350 ml (60%) is alveolar breath which is desired to be sampled, although it will be realised that these figures are merely exemplary.
  • step 230 the desired portion of breath to be sampled is selected.
  • Figure 3 illustrates an example of the pressure signal 131 output by the pressure sensor 130 during normal patient breathing. It will be realised that the voltages and time-duration of the signal 131 are merely exemplary.
  • the pressure signal 131 may be sampled at a predetermined frequency by the control unit 140, such as 2.5 KHz, although it will be realised that other sampling frequencies may be used.
  • filtering may be applied to the sampled pressure signal values, such as median filtering over a predetermined number of samples e.g. 1000 samples, although other numbers of samples and filter types, such as a modified average filter, may be utilised.
  • the pressure signal 131 is proportional to air pressure in the mask 110, such that a larger pressure signal indicates higher pressure in the mask 110 caused by the patient exhaling. It can be appreciated that the pressure signal 131 resembles a square wave for this example patient.
  • a time duration and average breath duration may be established from the pressure signal 131.
  • the predetermined portion of each breath may be determined directly from the pressure signal. The predetermined portion may be selected by an operator of the system 100 e.g. the patient or other operator such as a technician operating the system 100. The operator may select a delay time from a start of a breath for sampling the breath. For example, if it is determined that an average breath length of the patient is 45 seconds, the user may select a sampling delay of 25 seconds.
  • the delay may begin from a point in time at which the control unit 140 determines the pressure signal 131 to rise above a threshold pressure.
  • the threshold pressure may also be set by the user.
  • the time delay may be set by specifying a percentage of average exhaled breath length as calculated as a running average from breath cycle monitoring. Thus a percentage of the exhaled breath (corresponding to dead space breath in some embodiments) is discarded i.e. not sampled and the latter part of the exhaled breath (corresponding to the alveolar breath in some embodiments) is sampled.
  • the control unit 140 may be arranged to monitor the pressure signal to detect the end of the exhale cycle i.e. end of the alveolar breath and a beginning of the inhale cycle. At this point, the control unit 140 is arranged to control the valve 170 to cause breath to flow through the restrictor 150 so as to avoid sampling any air from the inhaled cycle (which would be air from the air supply).
  • control unit 140 applies further signal processing to the received pressure signal 131.
  • control unit 140 is arranged to differentiate the received pressure signal 131.
  • Figure 4 is a representation of the differentiated pressure signal 141. The edges of the breath are clearly visible in the differentiated pressure signal which deviates from zero according to the rate of change of the pressure signal.
  • the determination of the selected portion of breath is based on the differentiated pressure signal by the control unit 140.
  • hysteresis is applied to the differentiated pressure signal i.e. applying a different switching level according to the direction of pressure signal change, as will be appreciated.
  • the selected portion of the patient's breath is sampled by the sampling device 160.
  • the control unit 140 determines when a trigger point occurs i.e. when the pressure signal 131 or differentiated pressure signal reaches a particular value and then initiates the determined delay time, for example initiating a countdown timer to allow for exhalation of dead space air before exhalation of the predetermined portion of breath desired to be sampled e.g. alveolar breath. Once the timer expires, the control unit 140 is arranged to output the valve control signal 171 to the valve 170 indicating that the valve 170 should switch from directing air through the restrictor branch 146 of the sampling conduit 145 to the sampling branch 147 and the sampling device 160.
  • the control unit 140 Whilst the valve 170 directs air through the sampling branch 147, the sampling pump 180 draws exhaled air through the sampling device 160.
  • the control unit 140 is arranged to output a signal indicating that the valve 170 should return to drawing exhaled air through the restrictor branch 170 after a sampling time. In some embodiments if, during the sampling time, the pressure signal 131 indicates a decrease in pressure in the mask 110 indicative of the patient ceasing to exhale, the control unit 140 may cause the vale 170 to return to the restrictor branch 146 before expiry of the sampling time.
  • the system 100 shown in Figure 1 allows sampling of organic volatiles from a predetermined portion of the patient's breath, such as the alveolar portion.
  • FIG. 5 illustrates a system 200 according to a further embodiment of the invention.
  • the system 200 shown in Figure 5 comprises a mask 210 which is provided with breathable air 221 from an air source 220 via a filter 225.
  • a pressure sensor 230 is connected to the mask 210 via a pressure conduit 231 to measure air pressure in the mask 210 and to output a pressure signal 232 to a control unit 240.
  • Air is drawn from the mask 210 through a sampling conduit 245 by a sample pump 280, via either a restrictor branch 246 and a restrictor 250 or a sampling branch 247 and a sampling device 260 selectively according to a valve 270 controlled by a valve control signal 271 output from the control unit 240.
  • the system 200 shown in Figure 2 contains like parts and operates as the system previously described with reference to Figure 1.
  • the system 200 of Figure 5 includes a carbon dioxide (C0 2 ) sensor 290 for measuring a level of C0 2 .
  • the C0 2 sensor 290 is arranged for measuring the level of C0 2 present in air exhaled by the patient.
  • the C0 2 sensor 290 is arranged in a C0 2 sampling conduit 291 which feeds off the sampling conduit 245, although it will be realised that the C0 2 sampling conduit 291 may connect directly to the mask 210.
  • Air is drawn through the C0 2 sampling conduit 291 by a C0 2 sample pump 295.
  • the C0 2 sensor 290 outputs a C0 2 level signal 292 to the control unit 240.
  • the control unit 240 may control operation of the valve 270 to sample a selected portion of the patient's breath according to the air pressure signal 232 and the C0 2 pressure signal 292
  • embodiments of the invention may be envisaged which do not comprise an air pressure sensor 230 and solely utilise the C0 2 sensor 290. Further embodiments of the invention may also be envisaged which utilise one or more sensors additional to the air pressure sensor 230 and C0 2 sensor 290.
  • the system 200 may comprise a humidity sensor.
  • embodiments of the invention determine one or more characteristics of the patient's breath and sample a selected portion of the breath according to the one or more characteristics.
  • Figure 6 illustrates an embodiment of signal processing system 300 for handling an output of a sensor 310, such as the air pressure sensor 130, 230 or C0 2 sensor 290.
  • the signal processing system 300 receives a sensor output signal 311 and produces an output signal 331 indicative of a variance of the input signal 311 from an average level of the input signal 311.
  • the output signal may be provided to a control unit 340, such as control units 140, 240 previously described.
  • the sensor 310 is arranged to measure an air characteristic such as air pressure or C0 2 level and to output the characteristic signal 311 indicative thereof.
  • the sensor 310 is arranged to measure the characteristic of the breath exhaled by the patient.
  • the output signal 311 is amplified by an amplifier 320 to a suitable signal level to produce an amplified sensor signal 321.
  • the amplified sensor signal 321 is provided to a first input of an operational amplifier 330.
  • the signal 311 output by the sensor 310 is also provided to an analogue to digital converter (ADC) 350 which converts the analogue signal level 311 to a digital representation for processing by a processing unit 360 which determines an average level of the output signal 31 1.
  • ADC analogue to digital converter
  • the processing unit 360 may determine the average level over a predetermined period of time i.e. the preceding x seconds, or since the processing unit 360 was last reset i.e. measurement of the patient's breath began.
  • the processing unit 360 outputs a digital average signal 361 indicative of the average level of the sensor signal 311 which is received by a digital to analogue converter (DAC) 370 for converting the digital average level signal 361 to an analogue average signal 371.
  • DAC digital to analogue converter
  • a second input of the op-amp 330 is arranged to receive the average signal 371 indicating the average level of the sensor output 331 over the predetermined period of time and to subtract the average sensor signal 371 level from the amplified sensor signal 321 to remove the average offset value from the output of the sensor 310.
  • the control unit 340 receives the signal 331 which is indicative of the variation of the sensor signal 311 from the average level of the sensor signal i.e. without any offset. It will be realised that operation of some components in the system shown in Figure 6 may be integrated with other components.
  • Figure 7 illustrates a system 400 according to a further embodiment of the invention.
  • the system 400 shown in Figure 7 is based on that 200 shown in Figure 5, although it may also be based on that 100 shown in Figure 1, as will be explained. Unless otherwise described the system of Figure 7 operates as described with reference to Figure 5 and undue repetition is omitted for clarity.
  • the system 400 comprises a mask 410 which is provided with breathable air 421 from an air source 420 via a filter 425.
  • a pressure sensor 430 is connected to the mask via a pressure sensing conduit 431 to measure air pressure in the mask 410 and to output a pressure signal 432 to a control unit 440.
  • Air is drawn from the mask 410 selectively through one of a restrictor conduit 445 or a sampling conduit 446 by a sample pump 480. Selection of the restrictor conduit 445 or sampling conduit 446 is performed by a valve 470 in response to a valve control signal 471 output from the control unit 440.
  • the mask 410 has two outlet conduits 445, 446 connected directly thereto in the form of the restrictor conduit 445 and the sampling conduit 446.
  • the restrictor conduit 445 includes a restrictor device 450, which may be dummy sampling device i.e. having the same resistance to airflow there -through or a second sampling device.
  • the sampling conduit 446 includes a sampling device 460 for sampling a predetermined portion of the patient's breath, such as the alveolar portion.
  • a sampling device 460 for sampling a predetermined portion of the patient's breath, such as the alveolar portion.
  • having parallel restrictor and sampling conduits 445, 446 from the mask 410 may allow more accurate sampling of the predetermined portion of the patient's breath since exhaled breath is separately transported from the mask to the sampling device 460 from the air drawn through the restrictor 450.
  • the system 400 of Figure 7 may include a carbon dioxide (C0 2 ) sensor 490 for measuring a level of C0 2 in the air in the mask 410.
  • the C0 2 sensor 490 is shown connected to the mask 410 via a C0 2 sampling conduit 491.
  • the C0 2 sampling conduit 491 may be connected to other locations within the system. Air is drawn down the C0 2 sampling conduit 291 by a C0 2 sample pump 495.
  • the C0 2 sensor 490 outputs a C0 2 level signal 492 to the control unit 440.
  • the control unit 440 may control operation of the valve 470 to sample a selected portion of the patient's breath according to the air pressure signal 432 and the C0 2 pressure signal 492.
  • embodiments of the invention may be envisaged which do not comprise the C0 2 sensor 490; or the air pressure sensor 430 and solely utilise the C0 2 sensor 490. Further embodiments may also be envisaged which utilise one or more sensors other than the air pressure sensor 430 and C0 2 sensor 490.
  • the system may comprise a humidity sensor.
  • embodiments of the invention determine one or more characteristics of the patient's breath and sample a selected portion of the breath according to the one or more characteristics.
  • embodiments of the present invention can be realised in the form of hardware, software or a combination of hardware and software. Any such software may be stored in the form of volatile or non-volatile storage such as, for example, a storage device like a ROM, whether erasable or rewritable or not, or in the form of memory such as, for example, RAM, memory chips, device or integrated circuits or on an optically or magnetically readable medium such as, for example, a CD, DVD, magnetic disk or magnetic tape. It will be appreciated that the storage devices and storage media are embodiments of machine -readable storage that are suitable for storing a program or programs that, when executed, implement embodiments of the present invention.
  • embodiments provide a program comprising code for implementing a system or method as claimed in any preceding claim and a machine readable storage storing such a program. Still further, embodiments of the present invention may be conveyed electronically via any medium such as a communication signal carried over a wired or wireless connection and embodiments suitably encompass the same.
  • the signal processing and valve control performed by the control unit 140 may be implemented in a device with no user interface. The signal measurement processing, timing and valve control may be performed in the analogue or digital domains, or a mixture of analogue and digital.

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  • Health & Medical Sciences (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Medical Informatics (AREA)
  • Molecular Biology (AREA)
  • Veterinary Medicine (AREA)
  • Biophysics (AREA)
  • Pathology (AREA)
  • Engineering & Computer Science (AREA)
  • Biomedical Technology (AREA)
  • Heart & Thoracic Surgery (AREA)
  • Public Health (AREA)
  • Physics & Mathematics (AREA)
  • Surgery (AREA)
  • Animal Behavior & Ethology (AREA)
  • General Health & Medical Sciences (AREA)
  • Physiology (AREA)
  • Pulmonology (AREA)
  • Hematology (AREA)
  • Measurement Of The Respiration, Hearing Ability, Form, And Blood Characteristics Of Living Organisms (AREA)
  • Investigating Or Analysing Biological Materials (AREA)
  • Sampling And Sample Adjustment (AREA)

Abstract

Conformément à des modes de réalisation, la présente invention porte sur un système de prélèvement d'haleine (100, 200) comprenant : des moyens de réception d'haleine pour la réception d'haleine ; un capteur (130, 230, 290, 310) pour la détection d'une caractéristique de l'haleine reçue et l'émission d'un signal indicatif (131, 132, 232, 311) ; un dispositif de prélèvement (160) pour le prélèvement de l'haleine, le dispositif de prélèvement (160) étant disposé dans un conduit de prélèvement de sorte que l'haleine reçue ait un temps de transit prédéterminé du capteur (130, 230, 290, 310) au dispositif de prélèvement (160) ; un conduit de dérivation (146, 246) pour permettre à l'haleine de contourner le dispositif de prélèvement (160) ; une soupape (170, 270) conçue pour diriger de manière sélective l'haleine vers le dispositif de prélèvement (160) ou le conduit de dérivation (146, 246) ; et une unité de commande (140, 240) conçue pour recevoir le signe indicatif (131, 132, 232, 311), afin de déterminer le moment où la caractéristique de l'haleine reçue satisfait un seuil prédéterminé, et afin de commander la soupape (170, 270) pour diriger de manière sélective l'haleine reçue vers le dispositif de prélèvement (160) à la suite d'un retard sensiblement égal au temps de transit prédéterminé.
PCT/GB2011/052145 2010-11-05 2011-11-04 Appareil et procédés de prélèvement d'haleine WO2012059768A1 (fr)

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CN108245757A (zh) * 2017-12-20 2018-07-06 浙江大学 基于呼吸机管路的呼出气体采集装置
US10034621B2 (en) 2011-12-21 2018-07-31 Capnia, Inc. Collection and analysis of a volume of exhaled gas with compensation for the frequency of a breathing parameter
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US10568568B2 (en) 2014-08-27 2020-02-25 Capnia, Inc. Methods for immune globulin administration
US20210267483A1 (en) * 2020-02-28 2021-09-02 Picomole Inc. Apparatus and method for collecting a breath sample using an air circulation system
WO2021168542A1 (fr) * 2020-02-28 2021-09-02 Picomole Inc. Appareil et procédé de collecte d'un échantillon d'haleine à l'aide d'un système de circulation d'air
US11191449B2 (en) 2013-08-30 2021-12-07 Capnia, Inc. Neonatal carbon dioxide measurement system
WO2021250261A1 (fr) 2020-06-12 2021-12-16 Institut Mines Telecom Dispositif de prelevement des gaz expires par un patient
US11499916B2 (en) 2019-04-03 2022-11-15 Picomole Inc. Spectroscopy system and method of performing spectroscopy

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US9936897B2 (en) 2003-06-19 2018-04-10 Capnia, Inc. Breath end-tidal gas monitor
US10034621B2 (en) 2011-12-21 2018-07-31 Capnia, Inc. Collection and analysis of a volume of exhaled gas with compensation for the frequency of a breathing parameter
US10499819B2 (en) 2013-01-08 2019-12-10 Capnia, Inc. Breath selection for analysis
US11331004B2 (en) 2013-02-12 2022-05-17 Capnia, Inc. Sampling and storage registry device for breath gas analysis
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US11191449B2 (en) 2013-08-30 2021-12-07 Capnia, Inc. Neonatal carbon dioxide measurement system
US10568568B2 (en) 2014-08-27 2020-02-25 Capnia, Inc. Methods for immune globulin administration
CN108245757A (zh) * 2017-12-20 2018-07-06 浙江大学 基于呼吸机管路的呼出气体采集装置
US11506601B2 (en) 2019-04-03 2022-11-22 Picomole Inc. Resonant cavity system
US11499916B2 (en) 2019-04-03 2022-11-15 Picomole Inc. Spectroscopy system and method of performing spectroscopy
US20210267483A1 (en) * 2020-02-28 2021-09-02 Picomole Inc. Apparatus and method for collecting a breath sample using an air circulation system
WO2021168542A1 (fr) * 2020-02-28 2021-09-02 Picomole Inc. Appareil et procédé de collecte d'un échantillon d'haleine à l'aide d'un système de circulation d'air
EP4110179A4 (fr) * 2020-02-28 2024-03-20 Picomole Inc Appareil et procédé de collecte d'un échantillon d'air expiré à l'aide d'un récipient à volume contrôlable
EP4110182A4 (fr) * 2020-02-28 2024-03-20 Picomole Inc Appareil et procédé de collecte d'un échantillon d'haleine à l'aide d'un système de circulation d'air
US11957450B2 (en) * 2020-02-28 2024-04-16 Picomole Inc. Apparatus and method for collecting a breath sample using an air circulation system
FR3111266A1 (fr) 2020-06-12 2021-12-17 Institut Mines Telecom Dispositif de prélèvement des gaz expirés par un patient
WO2021250261A1 (fr) 2020-06-12 2021-12-16 Institut Mines Telecom Dispositif de prelevement des gaz expires par un patient

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