WO2014060602A1 - Ensembles de capture acoustique - Google Patents

Ensembles de capture acoustique Download PDF

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Publication number
WO2014060602A1
WO2014060602A1 PCT/EP2013/071904 EP2013071904W WO2014060602A1 WO 2014060602 A1 WO2014060602 A1 WO 2014060602A1 EP 2013071904 W EP2013071904 W EP 2013071904W WO 2014060602 A1 WO2014060602 A1 WO 2014060602A1
Authority
WO
WIPO (PCT)
Prior art keywords
acoustic
assembly according
chamber
housing
pickup assembly
Prior art date
Application number
PCT/EP2013/071904
Other languages
English (en)
Inventor
Frank Keane
Original Assignee
Vitalograph (Ireland) Limited
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 Vitalograph (Ireland) Limited filed Critical Vitalograph (Ireland) Limited
Publication of WO2014060602A1 publication Critical patent/WO2014060602A1/fr

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Classifications

    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
    • A61B7/00—Instruments for auscultation
    • A61B7/02—Stethoscopes
    • A61B7/04—Electric stethoscopes
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
    • A61B7/00—Instruments for auscultation
    • A61B7/02—Stethoscopes
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
    • A61B7/00—Instruments for auscultation
    • A61B7/003—Detecting lung or respiration noise

Definitions

  • This invention relates to acoustic pick-up assemblies, in particular for picking up noises generated internally of the human body, for example the heartbeat or noise caused by airflow when breathing.
  • a standard stethoscope For listening to heartbeat or breathing sounds, clinicians have long used a standard stethoscope. A diaphragm is held against the patient's chest, the diaphragm forming one side of a chamber which has a tubular connection to an earpiece, or more usually a pair of earpieces. The vibrations of the diaphragm are transmitted through the air in the chamber behind it and the tubular connection to the ears of the clinician. While standard stethoscopes are widely used in clinical diagnosis and monitoring, they are not suitable for continuous monitoring of a patient's heart or breathing. Additionally, the audible volume of the sound is relatively low which sometimes makes it difficult for the clinician adequately to hear what is going on.
  • WO/0134033 discloses a stethoscope transducer where the diaphragm forms one plate of a capacitor and circuitry connected to the capacitor is provided to product an audible signal for the user.
  • US 4582961 discloses a capacitative transducer forming part of a condenser microphone.
  • US 2009/021 1838A discloses a stethoscope construction with a diaphragm having a floating mass mounted on it and an acoustic transducer mounted on the floating mass.
  • Various types of transducer may be used.
  • Piezo-electric acoustic sensors for use in stethoscopes are disclosed in JP- A- 2000139904, EP-A-1053716 and WO/0035348.
  • the use of a conventional stethoscope is not convenient for continuous monitoring, for example to monitor a patient's breathing or heartbeat over a long period of time particularly over a period of hours or days. In particular, they are unsuitable for cough monitoring, i.e. monitoring the frequency and nature of persistent coughing.
  • the sound is captured by way of a transducer incorporated in a housing which is designed to be light in weight, easily applied to a patient for long periods of time, and which acts to enable faithful capture of the noises from within the body while being relatively insensitive to ambient external noise.
  • an acoustic pick-up assembly for long-term monitoring of the internal noise generated within the body of a patient, wherein the assembly comprises a housing having an electret transducer including a membrane of electret material mounted therein, and wherein the housing includes a chamber, one wall of which is covered by a diaphragm and with the electret transducer membrane constituting part of the opposite wall of the chamber, and wherein the housing further includes, surrounding the side walls of the chamber, one or more air gaps to reduce acoustic transmission between the outside of the housing and the electret transducer, and characterised in that the diaphragm is formed of material having an acoustic impedance similar t that of human skin and the side of the diaphragm away from the chamber carries an adhesive coating allowing the pick-up assembly to be adhered to the skin.
  • the electret transducer used is preferably of omni-directional type, most conveniently (because they are available as ready-made components) an electret condenser microphone insert unit.
  • a unit may conveniently be mounted on one side of a printed circuit board while preferably the other side of the printed circuit board carries areas to which wires may be attached, for example audio cable connectors or wires connecting the electret condenser microphone insert into a circuit forming part of a wireless signal transmission module.
  • the side of the electret transducer remote from the chamber is sealed to the housing via a permanently soft sealant material, for example silicone-based medical grade putty.
  • the diaphragm which is applied to the skin of a patient during use, is formed of a material having an acoustic impedance similar to that of human skin.
  • the diaphragm does not act in any capacitative fashion, but rather merely acts faithfully to transmit the acoustic vibrations from the skin into the chamber where they are picked up by the electret transducer.
  • a preferred material for the diaphragm is a polyurethane polymer elastic membrane. The use of such a membrane is preferred because it is tough and also
  • the elastic membrane preferably has a thickness of 0.05 to 0.25 mm and it is preferably a membrane of high tensile strength and substantial elongation before break.
  • the side of the diaphragm away from the chamber carries an adhesive coating serving to stick the pick-up assembly to the skin.
  • This is preferably a hydrocolloid gel type of adhesive as used in wound dressings.
  • Such materials are well-known to give rise to few problems, if any, when they are adhered to the skin for long periods of time, even in the case of sensitive skins. They absorb any exudates from the skin and retain their adhesion to the skin even if the skin is slightly moist.
  • the design of the housing may vary widely, but, as noted above, it defines a chamber which is sealed on one face by the diaphragm and where the opposite wall of the chamber to the diaphragm has the electret transducer set in it.
  • a highly preferred structure for the housing is that of a generally cylindrical chamber having means for mounting the electret transducer at one end of it, for example by way of a printed circuit board as described above, and where the chamber is surrounded on all of its sides save that destined to face the skin of the patient by outer housing parts which are suitably acoustically isolated from the chamber itself.
  • the acoustic isolation is easiest achieved by providing sealed chambers or pockets surrounding the chamber which has the electret transducer on one side.
  • the housing is preferably a simple lightweight plastics moulding, preferably of ABS copolymer.
  • acoustic pick-up assemblies in accordance with the present invention to reduce the amount of ambient noise which can reach the chamber and which accordingly can be picked up by the electret transducer. This may be done by ensuring that there is very little acoustic transmission from the outside of the housing to the chamber within it. Acoustic transmission is minimal across boundaries between materials having substantially different acoustic impedances. Thus, in the case of a housing made of ABS plastics, acoustic transmission is very small into the inner chamber because of the major difference of acoustic impedance between air and the ABS.
  • air typically has an acoustic impedance of 0.000429 MRyals while the acoustic impedance of ABS copolymer is usually around 2.3 MRyals.
  • ABS copolymer usually around 2.3 MRyals.
  • silicone putty is used to mount the PCB, very little sound transmission takes place through it because its acoustic impedance is usually around 1 .45 MRyals.
  • the area in which acoustic transmission is highly desired is across the diaphragm which is held in contact with the skin of the patient.
  • the acoustic impedance of skin is usually in the range of 1 .53 to 1 .68 MRyals, and a typical acoustic impedance of the preferred polyurethane diaphragm materials is around 1.55 MRyals. Accordingly, there is a good pick up of sound from the body cavity when, for example, an acoustic pick-up assembly according to the present invention is adhered to the patient's chest.
  • the acoustic impedance of the ABS housing about 2.3 MRyals which is close enough to the acoustic impedance of the skin to transmit the majority of the sound from the chest wall to the sensor housing.
  • Figure 1 is a perspective view of an acoustic pick-up assembly in accordance with the present invention
  • Figure 2 is a sectional view of the assembly shown in Figure 1 ;
  • Figure 3 is an exploded view of the assembly
  • Figure 4 is a plan and side view of the electrically active components of the pick-up.
  • the assembly consists of a housing 1 of generally cylindrical shape having adhered to one side of it a polyurethane membrane sheet 2.
  • Housing 1 consists of a generally cylindrical multi-compartmented component 4 with a central chamber 12 and a lid 3.
  • Component 4 has a series of annular walls surrounding chamber 12 as shown, some of which are slotted to receive an electrical signal cable 5.
  • the signal cable 5 terminates at one end in two wires which are soldered on to connection areas 9 on the back of a round printed circuit board 7 shown in more detail in Figures 3 and 4.
  • the front of the printed circuit board 7 carries an electret condenser microphone insert 6 of known type. At its other end, the lead 5 terminates in a standard jack plug 8.
  • the electrical assembly shown in Figure 4 is constructed by soldering the electret transducer 6 to one side of the PCB 7 and soldering the ends of the wires in lead 5 to appropriate terminal areas 9 on the other side of the PCB.
  • the PCB7 is then located centrally in the circular recess in the middle of the top of component 4, and the lead 5 positioned in slots 10 formed in the walls shown in component 4. This locates electret condenser microphone insert 6 as one end wall of cylindrical chamber 12.
  • a quantity of medical putty 1 1 is then applied to the back of the PCB 7 usually about 0.5 gm, and lid 3 then pressed on to the component 4 to close off the back of the PCB 7.
  • an annular wall 13 forming part of the lid 3 fits into the outermost annular air gap formed in component 4, and denoted 16 in Figures 2 and 3, while an inner annular wall 14 is a fit in on intermediate annular groove 15 in component 4.
  • Lid 3 may be secured into component 4 by means of an appropriate adhesive.
  • the quantity of medical putty 1 1 is pressed into place to prevent any direct air passage between the interior of the lid 3 and the location of lead 5.
  • the lid 3 may be secured in place by an appropriate adhesive.
  • the diaphragm 2 is adhered to the base of component 4 by an appropriate permanent rubbery adhesive composition.
  • the diaphragm 2 may be, if desired, a laminated structure consisting of a layer of elastic polyurethane film, a layer of a hydrocolloid adhesive, for example about 0.5 mm thick and a release paper sheet covering the hydrocolloid adhesive layer and shielding it from picking up dust or sticking to anything until the pick-up assembly is put to use by sticking it on to the skin of a patient.
  • the electric transducer 6 may be selected from a wide variety of such transducers commercially available.
  • a preferred transducer is an omnidirectional type having a sensitivity of around 38 db and a flat low frequency response down to around 20 Hz.

Landscapes

  • Health & Medical Sciences (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Physics & Mathematics (AREA)
  • Acoustics & Sound (AREA)
  • Heart & Thoracic Surgery (AREA)
  • Biomedical Technology (AREA)
  • Engineering & Computer Science (AREA)
  • Medical Informatics (AREA)
  • Molecular Biology (AREA)
  • Surgery (AREA)
  • Animal Behavior & Ethology (AREA)
  • General Health & Medical Sciences (AREA)
  • Public Health (AREA)
  • Veterinary Medicine (AREA)
  • Measuring And Recording Apparatus For Diagnosis (AREA)

Abstract

L'invention concerne des ensembles de capture acoustique destinés à être utilisés dans la surveillance à long terme de sons cardiaques ou pulmonaires dans le corps d'un patient. Les ensembles comprennent un boîtier ayant un transducteur électret (6) placé à l'intérieur de ceux-ci. Dans une construction typique, le boîtier comprend une base de type disque rond et un couvercle, la base comprenant des poches d'air annulaires pour une isolation acoustique et ayant, formée à l'intérieur de celle-ci, une chambre sur un côté de laquelle se trouve le transducteur électret (6) et dont l'autre coté est formé par une membrane élastique (2) qui peut être adhérée à la peau du patient avec un adhésif hydrocolloïde.
PCT/EP2013/071904 2012-10-19 2013-10-18 Ensembles de capture acoustique WO2014060602A1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
GB201218867A GB2507113A (en) 2012-10-19 2012-10-19 Acoustic pick-up assemblies
GB1218867.8 2012-10-19

Publications (1)

Publication Number Publication Date
WO2014060602A1 true WO2014060602A1 (fr) 2014-04-24

Family

ID=47359194

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/EP2013/071904 WO2014060602A1 (fr) 2012-10-19 2013-10-18 Ensembles de capture acoustique

Country Status (2)

Country Link
GB (1) GB2507113A (fr)
WO (1) WO2014060602A1 (fr)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN107249440A (zh) * 2015-03-16 2017-10-13 努沃集团有限公司 用于腹部胎儿心脏活动检测的声学传感器

Families Citing this family (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP6210417B2 (ja) 2014-05-15 2017-10-11 パナソニックＩｐマネジメント株式会社 生体音センサおよび生体音診断装置
GB2574040B (en) * 2018-05-24 2021-02-10 Acurable Ltd Enclosure
CN110179493A (zh) * 2019-05-08 2019-08-30 四川新源生物电子科技有限公司 一种具备隔音降噪功能的免提式听诊头

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5853005A (en) * 1996-05-02 1998-12-29 The United States Of America As Represented By The Secretary Of The Army Acoustic monitoring system
US6438238B1 (en) * 2000-07-14 2002-08-20 Thomas F. Callahan Stethoscope
US20040032957A1 (en) * 2002-08-14 2004-02-19 Mansy Hansen A. Sensors and sensor assemblies for monitoring biological sounds and electric potentials
US20050124902A1 (en) * 2003-12-01 2005-06-09 Inovise Medical, Inc. Electrical and audio anatomy-signal sensor system
US20090211838A1 (en) * 2008-02-27 2009-08-27 Silutions Technologies, Inc. Floating Ballast Mass Active Stethoscope or Sound Pickup Device

Family Cites Families (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DK146770C (da) * 1981-11-13 1984-06-04 Brueel & Kjaer As Kapacitiv transducer
US6498854B1 (en) * 1999-10-28 2002-12-24 Clive Smith Transducer for sensing body sounds
US7110804B2 (en) * 2003-04-24 2006-09-19 Inovise Medical, Inc. Combined electrical and audio anatomical signal sensor

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5853005A (en) * 1996-05-02 1998-12-29 The United States Of America As Represented By The Secretary Of The Army Acoustic monitoring system
US6438238B1 (en) * 2000-07-14 2002-08-20 Thomas F. Callahan Stethoscope
US20040032957A1 (en) * 2002-08-14 2004-02-19 Mansy Hansen A. Sensors and sensor assemblies for monitoring biological sounds and electric potentials
US20050124902A1 (en) * 2003-12-01 2005-06-09 Inovise Medical, Inc. Electrical and audio anatomy-signal sensor system
US20090211838A1 (en) * 2008-02-27 2009-08-27 Silutions Technologies, Inc. Floating Ballast Mass Active Stethoscope or Sound Pickup Device

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN107249440A (zh) * 2015-03-16 2017-10-13 努沃集团有限公司 用于腹部胎儿心脏活动检测的声学传感器

Also Published As

Publication number Publication date
GB2507113A (en) 2014-04-23
GB201218867D0 (en) 2012-12-05

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