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`
`U5005853005A
`
`[19]
`United States Patent
`5,353,005
`[11] Patent Number:
`
`
` Scanlon [45] Date of Patent: *l)ec. 29, 1998
`
`
`
`[54] ACOUSTIC MONITORING SYSTEM
`
`4,619.2?o unless Margolis cl al.
`4.630.614
`1231986 Atlas .
`
`.
`
`[75]
`
`Inventor: Michael V. Scanlon, Silver Spring, Md.
`
`[73] Assignee: The United States of America as
`represented by the Secretary of the
`Ar'mtr Washin [on D (‘
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`beyond lhc expiration date- 01 P311 N01
`5,515,865.
`
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`I * 1 NW“:
`
`l'll Appl' No" 643’139
`[22]
`Filed:
`May 2, 1996
`
`[52] U.S. Cl.
`
`[51]
`
`[58]
`
`l56l
`
`_
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`US. PATENT DOCUMENTS
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`OTHER PUBLICATIONS
`
`Monitoring of Breathlng With a Segmclnal Air—[*1le Mat-
`tress J. Gundcrscn and K. Dahlin, Med & Biol Engng, vol.
`9, p. 541 Pcrgarnon Press 1971. Printed in Great Britain.
`
`‘
`
`Primary Examiner—Mickey Yu
`Assistant EZrmniner—Dinh X. Nguyen
`Attorney; Agent, or Firm—Paul S. Clohan, Jr.; William
`lishelman; Mark Kelly
`-
`7
`ABSTRACI
`[3 l
`A transducer in communication with fluid in a pad held in
`close contact against a sound or movement source monitors
`acoustic signals transferred into the lluid. The signal pattern
`is monitored aurall).r andior compared to predelcrmined
`reference patterns, and optional control and stimulation
`means can be activated in response to the comparison
`results. The sensed acoustic signal can he Iransmitted to a
`remote receiver or prom-:Ssed locally. 'I'ypieully, the acoustic
`Signal is representative of the heartbeat or breathing of a
`living organism. The monitoring system may he applied to
`diverse situations including SIDS, apnea, home baby
`monitoring, medical transport devices, blood pressure cutfs.
`seals Combat casually care and hand-held devices
`"
`"
`
`96 Claims, 12 Drawing Sheets
`
`370
`
`310
`
`315
`
`
`
`0001
`
`US. Patent No. 8,652
`
`Apple
`APLl
`
`
`
`Apple Inc.
`APL1054
`U.S. Patent No. 8,652,040
`
`0001
`
`

`

`Dec. 29, 1998
`
`Sheet 1 0f 12
`
`5,853,005
`
`FIGURE 3
`
`
`US. Patent
`
`0002
`
`0002
`
`

`

`US. Patent
`
`Dec. 29, 1998
`
`Sheet 2 0f 12
`
`5,853,005
`
`FIGURE 4
`
`FIGURE 5
`
`
`
`FIGURE 6
`
`0003
`
`0003
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`

`

`90
`
`12
`
`92
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`94-
`
`FIGURE 7
`
`FtGURE 9
`
`
`US. Patent
`
`Dec. 29, 1998
`
`Sheet 3 0f 12
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`5,853,005
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`92
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`12
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`0004
`
`0004
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`US. Patent
`
`Dec. 29, 1998
`
`Sheet 4 0f 12
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`5,853,005
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`
`
`104
`
`104
`
`FIGURE 10
`
`118 12 14
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`112 108
`
`10
`
`FIGURE 12
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`
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`
`124
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`116
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`12
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`106
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`122
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`0005
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`0005
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`US. Patent
`
`Dec. 29, 1998
`
`Sheet 5 0f 12
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`124
`
`12
`
`106
`
`12
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`14 62 129
`105
`FIGURE 14
`
`5,853,005
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`56
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`
`FIGURE 15
`
`
`
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`193E“
`
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`
`68
`
`0006
`
`0006
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`

`

`US. Patent
`
`Dec. 29, 1998
`
`Sheet 6 0f 12
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`5,853,005
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`FiGURE 17
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`141
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`14a Mb 1.36
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`120
`
`12b
`
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`
`
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`_EWK‘E11-m-
`
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`
`FIGURE 18
`
` STEREO AMPLIFIER,
`
`FlLTERS, OTHER
`COMPONENTS
`
`‘5
`
`138
`
`0007
`
`0007
`
`

`

`US. Patent
`
`Dec. 29, 1998
`
`Sheet 7 0f 12
`
`5,853,005
`
`HGURE 20
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`HGURE 21
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`
`
`
`62
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`12
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`110
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`154
`
`155
`
`0008
`
`0008
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`

`

`Dec. 29, 1998
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`Sheet 8 0f 12
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`5,853,005
`
`FIGURE 24
`
`
`US. Patent
`
`0009
`
`0009
`
`

`

`US. Patent
`
`Dec. 29, 1998
`
`Sheet 9 0f 12
`
`5,853,005
`
`FIGURE 25
`
`35
`
`
`
`FIGURE 27
`
`a
`
`178
`
`V
`
`FIGURE 26
`
`180
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`
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`0010
`
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`
`

`

`US. Patent
`
`Dec. 29, 1998
`
`Sheet 10 0f 12
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`5,853,005
`
`1 81
`
`FIGURE .30
`
`
`184
`
`
`FIGURE 28
`
`0011
`
`0011
`
`

`

`US. Patent
`
`Dec. 29, 1998
`
`Sheet 11 01' 12
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`5,853,005
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`190
`
`106
`
`FIGURE 31
`
`196
`
`FIGURE 3.3
`
`12
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`
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`14
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`12
`
`FIGURE 32
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`211
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`
`0012
`
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`

`

`US. Patent
`
`Dcc.29,1998
`
`Sheet 12 of 12
`
`HGURE 35
`
`
`
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`5,853,005
`
`HGURE 34
`
`0013
`
`0013
`
`

`

`
`
`5,853,005
`
`1
`ACOUSTIC MONITORING SYSTEM
`
`BACKGROUND OF THE INVENTION
`
`1. Field of the Invention
`
`The present invention relates to a sound and movement
`monitor suitable for detecting activity and, more
`particularly, to a sound and movement monitor suitable for
`providing the capability to locally or remotely monitor
`living organism body functions.
`2. Discussion of the Related Art
`
`it]
`
`35
`
`4O
`
`The acoustic signatures of various body functions, such as
`hean rate, pulmonary function, respiration, ete., provide
`valuable input to the medical caregiver in diagnosing medi-
`cal conditions and monitoring responses to changed circum—
`stances and treatments. Moreover, patterns of such acoustic
`activity can be used to identify the presence or even the
`onset of reduced physical ability or condition and
`concurrently, mental alertness. Anticipation of such condi-
`tions can allow intervention to avoid hazardous situations
`resulting from diminished capacity, as for instance, in the
`operation of motor vehicles and heavy machinery.
`Several problems have hampered elIorts to effect practical
`systems that would perform ongoing biological monitoring
`with and without feedback stimulation. In many environ- *
`ments the ambient noise renders airborne transmission of
`pertinent signals ineffective. Moreover, airborne coupling
`mechanisms, such as conventional stethoscopes, are insuf-
`ficiently efl'icient
`to provide the necessary definition and
`distinction between competing acoustic pulses. 0n the other
`hand, invasive monitoring techniques such as implants and
`fixed—position transducers are too inconvenient and uncom—
`fortable for widespread application.
`Accordingly, there exists in the prior art a long felt need
`for a passive non-invasive acoustic and movement monitor
`suitable for simply and remotely providing body function
`monitoring, particularly one easily adaptable to providing
`biofeedback stimulation to the monitored organism.
`
`15
`
`3o
`
`SUMMARY OF THE INVENTI ON
`
`It is accordingly one object of the present invention to
`overcome the above mentioned disadvantages of the prior
`art and to monitor biological activity of a living organism
`using an improved acoustic monitoring system.
`It is a further object of the present invention to vauirc a
`signal corresponding to the acoustic activity or movement of
`a living organism and to transmit that signal to a remote
`receiver.
`
`It is yet another object of the present invention to provide
`an acoustic monitoring system which produces an output
`signal corrected for ambient noise.
`It is another object of the present invention to provide an
`acoustic monitoring system having multiple transducers for
`providing signal directional information.
`It is. also an object of this invention to provide an acoustic
`monitoring system having a sensor pad formable to the
`contours of support surfaces.
`An acoustic monitoring system in accordance with the
`present invention includes a fluid-filled sensor pad adapted
`to conform to at least a portion of the surface of a living
`organism and acoustic transducing means for monitoring
`and converting acoustic signals received by the pad into
`electrical signals corresponding to the acoustic signals.
`The “transducing means" can be any type of sensor or
`transducer, where by “transducer” is meant a microphone or
`
`45
`
`50
`
`55
`
`60
`
`65
`
`0014
`
`2
`similar means for picking up acoustic signals (e.g.,
`heartbeat) andfor varying pressure signals. For example, the
`transducer could be a vibratory andior movement sensor,
`such as an accelerometer, a strain gage, an optical displace-
`ment sensor, or a fiber—optic sensor. Chemical, biological,
`and electrical emission sensors could also be used as a
`transducer to indicate the condition of the object in accor-
`dance with the present invention.
`The transducer output, in accordance with the preferred
`embodiment, can be transmitted to a remote location and
`monitored by audio and visual indicators of sensor activity.
`Respiratory, pulmonary, digestive, and vocalived sounds
`transduced can be recreated at
`the remote monitor, or
`transmitted to medical personnel for diagnosis and treat-
`ment. A remote station could be configured to monitor one
`or several sensor pads simultaneously, and selectively
`choose to monitor each of the trausducer’s audio output.
`A stimulator can also be provided to generate vibratory,
`oscillatory or shaking movement of the fluid within the pad.
`If provided, the stimulator also can generate an audible noise
`to stimulate the object acoustically, or a light source to
`stimulate the object visually. Additionally, electrical,
`chemical, mechanical, or other energy sources could be used
`as a stimulator.
`
`The sensor pad preferably has characteristics sufficient to
`transmit to the transducer the movement from the object in
`the form of at
`least one of breathing, heart and motion
`sounds of the object. The shape and performance features of
`the pad will be tailored to each application, such as for use
`in a crib, cuff, vehicle seat, or gurney. The sensor pad and
`transducer could aLso be built into existing products. In a
`preferred embodiment, the sensor pad is liquid—filled with a
`pressure transducer arranged in communication with the
`internal volume of the pad such that forces applied to the pad
`by the object cause pressure changes which are detected by
`the pressure transducer, The pressure transducer provides an
`output proportional to the pressure changes, and preferably
`can also discriminate between the physical presence and
`absence of an object placed upon the sensor pad.
`The sensor pad may be a bladder or pouch having sidewall
`surfaces sufficiently rigid to readily transmit pressure fluc-
`tuations from the object to the transducer. These surfaces
`should allow acoustic signals to be transmitted through the
`walls, facilitating communication between the object, fluid
`medium, and transducer.
`The invention may furl her comprise an alarm selectively
`activated by the monitoring system when the output from the
`transducer corresponds to preselected movement or sound
`patterns from the object such as the onset of measurable
`symptoms indicative of certain conditions, such as falling
`asleep, snoring, or choking.
`Still other objects and advantages of the present invention
`will become readily apparent to those skilled in this art from
`the following detailed description, wherein only the pre—
`ferred embodiments of the invention are shown and
`described, simply by way of illustration of the best mode
`contemplated of carrying out
`the invention. As will be
`realized,
`the invention is capable of other and different
`embodiments, and its several details are capable of modifi-
`cations in various obvious respects, all without departing
`from the invention. Accordingly. the drawings and descrip-
`tion are to be regarded as illustrative in nature, and not as
`restrictive.
`
`BRIEF DESCRIPTION OF THE DRAWINGS
`
`FIG. 1 is an illustration, partly in schematic form, of an
`acoustic monitoring system according to the present inven-
`tion.
`
`
`
`0014
`
`

`

`
`
`3
`FIG. 2 is a perspective view, partly in section, of an
`exemplary sensor pad that may be used to practice the
`present invention.
`FIG. 3 is a perspective view, partly in section, of another
`exemplary sensor pad that may be used to practice the
`present invention.
`FIG. 4 is a perspective view of an acoustic monitoring
`system according to the present
`invention installed on a
`medical gurney.
`FIG. 5 is a perspective view of an acoustic monitoring
`system according to the present invention installed on a
`stretcher.
`
`FIG. 6 is a perspective view of an acoustic monitoring
`system according to the present
`invention installed on a
`wheel chair.
`
`FIG. 7 is a fragmentary view of a human torso with
`acoustic monitoring systems applied to the chest with a
`shoulder strap and a second monitor applied to the abdomen
`with a belt.
`
`FIG. 8 is a plan view of the chest—mounted sensor pad of
`FIG. 7.
`
`FIG. 9 is a perspective view of a bed and pillow each
`provided with acoustic monitoring systems according to the
`present invention.
`FIG. 10 is a perspective view of an animal lift mechanism
`equipped with sensor pads according to the present inven-
`tion.
`
`FIG. 11 is a view in cross—section of a hand-held pocket-
`clip version of an acoustic monitoring system according to
`the present invention.
`FIG. 12 is a cross-section of a hand-held hemispheric
`acoustic monitoring system according to the present inven-
`tion.
`
`FIG. 13 is a cross-section of a hand-held parabolic acous-
`tic monitoring system according to the present invention.
`FIG. 14 is a cross-section of a vacuum-attaching embodi-
`ment of an acoustic monitoring system according to the
`present invention.
`FIG. 15 is an illustration. partly in section and partly
`schematic. of a baby crib equipped with an acoustic moni-
`toring system according to the present invention.
`FIG. 16 is a partial perspective view of a fluid-mounted
`reference sensor shown in cu taway.
`FIG. 17 is a cross-section of a single compartment acous-
`tic monitor blood pressure cuff according to the present
`invention.
`
`FIG. 18 is a perspective view in partial cutaway of a
`multi-pad acoustic monitor cuff configured as a blood-Howl
`blood pressure monitor.
`FIG. 19 is a broken cross-section of a folded exponential
`horn and an exponential horn embodiment of the present
`invention each in fluid communication with a single trans-
`ducer.
`
`lilG. 2|] is a side view of an acoustic monitoring system
`according to the present
`invention applied to a pregnant
`woman to monitor l’etal heartbeat activity.
`FIG. 21 is a cross-section view of a swallowahlc capsule
`configured with an acoustic monitoring system according to
`the present invention.
`FIG. 22 is a perspective view of an arm chair having an
`acoustic monitoring system according to the present inven~
`tion installed in the chair back and arm rests.
`
`FIG. 23 is a side view of an acoustic monitoring system
`according to the present invention installed in the back and
`head rest of a recumbent exercise bicycle.
`
`ll]
`
`15
`
`3n
`
`35
`
`40
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`45
`
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`
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`
`60
`
`65
`
`0015
`
`portions or surfaces specifically intended to prevent trans-
`
`5,853,005
`
`4
`FIG. 24 is a cross-section of an acoustic monitoring
`system according to the present
`invention with shape-
`retaining internal stiffening structure for supporting vertical
`orientations.
`
`FIG. 25 is a perspective view in partial cutaway of an
`acoustic monitoring system built into a vehicle seat back and
`seat belt for monitoring driver alertness.
`FIG. 26 is a top view of the interior of a hat or cap
`configured with an acoustic monitoring system according to
`the present invention attached to the hatband.
`FIG. 27 is a perspective view of an acoustic monitoring
`system according to the present invention attached to eye-
`glasses.
`FIG. 28 is a perspective view of an acoustic monitoring
`system according to the present invention attached to a pair
`of goggles.
`FIG. 29 is a perspective view in partial cutaway of an
`acoustic monitoring system according to the present inven-
`tion built into ear plugs.
`FIG. 30 is a cross-section of an adhesive-mounted acous-
`tic monitoring system.
`FIG. 31 is a view in cross-section of a stethoscope
`according to the present invention.
`FIG. 32 is a broken cross-section of an acoustic monitor-
`ing system according to the present invention configured to
`transmit sensed signals over telephone lines.
`FIG. 33 is a cutaway view of an embodiment of the
`invention in the form of an earpiece.
`FIG. 34 is a variation of the embodiment of FIG. 33.
`
`FIG. 35 is a cutaway view of an embodiment of the
`invention in the form of a pacifier.
`DESCRIPTION OF THE PREFERRED
`EMBODIMENT
`
`An acoustic monitoring system 10 according to the
`present invention, as showu in FIGS. 1 and 2, includes a
`sensor pad 12 defining a
`fluid-filled chamber 11 and a
`sensing and monitoring system 13 including an acoustic
`pressure transducer 14 acoustically coupled with the cham-
`ber and a signal processing and output system 15 for
`processing output signals from the transducer caused by
`pressure fluctuations in the pad such as may be caused by
`biological activity ofa living organism 19 in contact with the
`pad.
`Sensor pad 12 is shown as a generally flat bladder having
`opposed, generally rectangular top and bottom walls 1'7 and
`18 and side walls 2|] transversely connecting peripheral
`edges of the top and bottom walls to define the chamber
`therebetween. 'l'he dimensions of the sensor pad are depen—
`dent upon the availablc area for the specific application and
`on maximizing the acoustical contact between the pad and
`the organism. For example, the size or dimension of the pad
`could be as large as a person’s torso. small enough to
`pert‘on'n pinpoint (localized) acoustic observations on a
`joint. or miniaturized to be swallowed. The pad can be
`formed of any suitable material including, but not limited to,
`plastic and rubber materials. but is preferably formed of a
`polychloroprene rubber, which has a characteristic of
`becoming acoustically transparent when submerged in water
`(as simulated by sandwiching the material between a human
`body and an appropriate fluid within the pad). Portions of the
`pad which contact
`the organism should have good sound
`transmission properties without absorbing the acoustic pres-
`sure iluctuations of interest; however, the pad may also have
`
`0015
`
`

`

`5,853,005
`
`
`
`5
`mission from other acoustic sources not intended for moni-
`toring. The rigidity of the walls of the sensor pad must also
`facilitate acoustic transmission without being flexible
`enough to conform to a patient's face so as not to restrict
`breathing.
`Chamber 11 is preferably filled with a fluid such as water
`to provide superior acoustic coupling between the pad and a
`living organism such as a human body, which is mostly
`water, thereby improving signal-to-noise ratio over ambient
`sounds and allowing medical personnel
`to detect sounds
`which are often difficult to discern, such as fluid in the lungs,
`an obstructed airway, or an irregular heart beat. Other fluids
`that can be used include saline solution, oil, alcohol, thick-
`sotropic fluids such as aerogels and gets 01' any other suitable
`materials which will couple well with a living organism and
`transmit acoustical signals adequately. ‘l'hicksotropic
`materials, that is, materials which do not flow under their
`own weight but which are easily deformed, will also dampen
`fluid oscillations resulting from motion or vibration.
`Acoustic transducer 14 is shown mounted in a side wall
`
`in
`
`15
`
`of the sensor pad but can be mounted, suspended or carried
`in any position on or within the sensor pad so long as it is
`acoustically coupled with the fluid. The transducer is pref-
`erably a piezoelectric, electret, or condenser-based
`hydrophone, similar to those used by Navy in sonar _
`applications, but can be any other type of suitable water-
`proof pressure and motion sensing type of sensor. Utilization
`of an instrumentation grade hydrophone allows collection of
`calibrated wide band acoustic data since ltydrophones cart
`have a flat omni-directional frequency response from less
`than about 1 Hz to about 160 kHz with excellent sensitivity
`and durability. Frequency response of the transducer and pad
`design can be tailored for anticipated acoustic targets. For
`example, the majority of the frequency content of human
`physiological sounds is in the range of 10 to 400 Hz,
`however, acoustic information exists in the infrasonic
`(below the typical 20 Hz limit of normal hearing) and
`ultrasonic (above 20 kltz) regions. lnfrasonic sounds cannot
`be detected by human ears, regardless of the amplitude, but
`a hydrophone with infrasonic response can detect
`these
`signals, and the information can be presented to the listener
`by either visual methods or frequency translation Schemes
`that shift
`infrasonic sounds into the audible region,
`if
`desired.
`
`3f]
`
`35
`
`4U
`
`The signal processing and output system 15 receives an
`output signal 28 from transducer 14, processes the signal and
`provides an output 30. System 15 is preferably battery-
`operated and may, for example, be identical or similar to the
`circuitry disclosed in applicant’s co-pending US. patent
`applications Ser. No. 08i292,441, filed Aug. 17, 1994 now
`abandoned and Ser. No. ($331,081, filed Apr. 22, 1994,
`now US. Pat. No. 5,515,865, the disclosures of which are
`incorporated herein by reference. Other circuitry which may
`be used is disclosed in FIGS. 9 and 11 of U.S. Pat. No.
`4,862,144,
`the disclosure of which is also incorporated
`herein by reference. The above-mentioned circuits deal
`primarily with baby monitoring and stimulation techniques
`for Sudden Infant Death Syndrome {SIDS}, apnea or general
`monitoring of people placed on a pad. Other types of signal
`processing can include broad—band amplification, narrow
`band filtering, variable gain, automatic gain control (AGC),
`use of an adaptive filter for noise cancellation, neural net
`identification, FFT or wavelet—based analysis or
`decomposition,
`joint
`time frequency analysis, voice
`processing, transfer functioning correlation techniques, tem-
`plate matching, beam-forming algorithms,
`level detection
`(with threshold), timing measurements, harmonic analysis,
`
`45
`
`50
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`
`0016
`
`6
`use of decision trees, comparison with a data base and
`auto-calibration. Output 30 can be fed to a post-processing
`unit 32, such as a speaker or head-set, a transmitter for
`remote monitoring, a display showing data from the sensor
`or analyzed data or conclusions, storage media or post—
`processing system,
`local andfor remote indicators using
`sound,
`light,
`radio frequency signals or mechanical
`indication, or a reaction mechanism for stimulating,
`resuscitating, shocking, notifying or paging the living organ-
`ism or alerting a caretaker. Output 30 can also be connected
`to most data acquisition systems, such as analog or digital
`audio tape recorders, strip charts or computer acquisition
`boards to record not just the occurrence of physiological
`events but tonal and temporal qualities as well. The trans-
`ducer 14 and signal processor and output system 15 should
`be battery operated to remove any chance of electrocution;
`however, AC power sources can be used if appropriate
`electrical isolation is ensured.
`
`In use, pad 12 is filled with a fluid medium such as water
`and is made to support or contact a living organism or
`animate object such as the human body shown in FIG. 1 at
`19. When filled with a fluid having acoustical properties
`similar to that of the organism,
`the pad acts as a fluid
`extension of the organism to function as an acoustical
`conduit or extension to transducer 14 within the pad thereby
`enabling the transducer to collect high signal—to—noisc ratio
`acoustic signals generated by the organism. In the case of a
`human body, this may allow medical personnel
`to detect
`sounds which are often difficult to discern, such as fluid in
`the lungs, an obstructed airway or an irregular heart beat.
`Generally, fluctuations in the fluid associated with acoustics
`or motion of the body will be converted to a voltage output
`by transducer 14. The electrical output of the transducer can
`then be filtered, amplified, analyzed andior transmitted by
`system 13, depending upon the specific application. Acousw
`tical analysis of the sensor pad output provides amplitude,
`phase, frequency, duration, rate and correlative information
`that may be useful for medical diagnosis, patient care and
`research, and such analysis may be performed in the field, in
`transit or at a medical facility. Traditional diagnostic meth-
`ods such as listening to an audio output and looking at a
`voltage-versus-time wavefonn can be augmented by joint
`time-frequency domain analysis techniques, neural
`networks, wavelet based techniques or template matching,
`for example. In addition, sensed acoustic signals may be
`used to aid in diagnosis and may be compared to a database
`of acoustic signatures or to past experience, either locally or
`via telemedical monitoring systems.
`Effective attenuation of unwanted ambient background
`noise results from the poor coupling between the airborne
`noise and the fluid-filled pad. In addition, acoustical and
`vibration isolation can be implemented in the sensor pad
`using materials like lead, foam, voids, absorber materials,
`acoustic gasket, suspension structures and anechoic materi-
`als. External and internal coatings, baffles and isolators can
`be configured to make certain areas of the sensor pad more
`sensitive to the acoustic target or body, and can help reject
`those sounds that may interfere with the diagnosis. When
`applied on the inner or outer surfaces of the pad, absorptive
`or anechoic materials can reduce reflections and selectively
`limit transmission to the fluid from various directions.
`
`Heater elements with thermostats can be incorporated into
`the sensor pad, but should be electrically isolated and in a
`safe location. Thermoelectric coolers, heaters, warm or cold
`fluid flow (circulation like chillers or hot water heater), or
`evaporative cooling could also be implemented.
`Aural
`interpretation of the sensor output and acoustic
`
`signature analysis can indicate cessation of breathing or
`
`0016
`
`

`

`
`
`7
`heart beat, or other conditions, such as a partially obstructed
`airway, sucking chest wound, hyperventilation, asthma,
`murmurs, or can be used to detect subtle attributes of the
`acoustic signature that may not he noticed by auscultation or
`merely viewing the sensor's voltage—versus—time output.
`Sensor output may also be used to predict or diagnose
`disease or medical conditions such as epileptic seizures,
`heart attack, apnea, SIDS, or other conditions that may have
`some acoustic signature that is modified before, during, or
`after occurrence. Advance signal-processing techniques can
`enhance the signature through filtering or array processing,
`can determine the proper level of response for the indicated
`condition, and can alert attendants via transmitter or alarm
`that immediate attention or resuscitation is necessary. This
`information can be transmitted by various methods to other
`personnel or hardware for remote diagnosis, verification,
`data logging or additional signal processing, and can be used
`to supplement diagnostic equipment such as EEG, EKG,
`ECG, MRI, CT, scanners, Doppler echocardiograrn, or other
`invasive or non-invasive technologies. By simultaneously
`monitoring acoustics with other forms of medical analysis
`equipment, the pad can provide a new dimension in patient
`care and research, for example, being able to both see and
`hear a heart valve closing, or to simultaneously view and
`listen to the sounds of an injured knee or ankle in motion.
`Transducer 14 can be disposed within fluid-filled chamber
`11 as shown or can be located a predetermined distance from
`the chamber and communicated with the chamber via a
`fluid—filled conduit or the like extending from the chamber as
`shown by broken lines in FIG. 2 at 16. In addition, the sensor
`pad can be formed with internal structures or partitions, as
`shown by broken lines in FIG. 2 at 22, to maintain the shape
`of the pad and to prevent complete constriction, as Well as
`to define acoustic conduits which facilitate acoustic sensing
`by transmitting pressure fluctuations efficiently to the pres-
`sure transducer 14. Partitions 22 can be straight or curved
`and preferably extend upwardly from bottom wall 18 to
`terminate at an upper edge vertically spaced from top wall
`17 when the sensor pad is not in use. It will be appreciated,
`however, that the partitions can depend downwardly from
`the top wall or that some of the partitions can extend
`upwardly from the bottom wall while others depend down-
`wardly from the top wall, as desired.
`Partitions 22 can also he used to define multiple chambers
`within the pad, as shown in FIG. 3 at 24a, 24b, 24c, etc,
`each with a transducer 14 disposed therein or in communi-
`cation therewith. [n this manner, a plurality of transducers
`can be placed within the pad for
`focused or sectional
`monitoring, wherein each of the transducers is monitored
`individually or selectively or a combined output is moni-
`tored. The walls or partitions can be formed of an acousti-
`cally insulative material to prevent internal chambers of the
`pad from communicating with one another or the walls can
`be acoustically transparent. The data from each individual
`transducer can be used to assess signal strength and time-
`ot‘-arrival at various positions in the body, or origin ofsound
`source, or to remove interfering noise sources such as the
`mother's heartbeat when trying to listen to a fetal heartbeat.
`More than one transducer can be employed using various
`array and noise canceling techniques. Issues such as signa—
`ture complexity, cost, available area and application purpose
`will help determine whether arrays or single transducers
`would perform better, and how the signal should be pro
`cesscd.
`
`The sensor pad of the acoustic monitoring system accord-
`ing to the present invention can be carried on or built into a
`body support surface of any type of medical transport device
`
`it]
`
`15
`
`so
`
`35
`
`4-0
`
`45
`
`50
`
`55
`
`60
`
`65
`
`0017
`
`5,853,005
`
`8
`such as, for example, a gumey, an evacuation stretcher, or a
`wheel chair. In FIG. 4, for example, a sensor pad 12 is
`configured to be attached across the top or support surface
`'79 of a gurney 80 using straps or hands 81 that wrap around
`the support surface. A transmitter, battery, electronic cir—
`cuitry and other components of the acoustic monitoring
`system can be attached to the straps or the gurney close to
`the sensor as shown schematically at 13 in FIG. 4. A
`stretcher 82 is shown in FIG. 5 with a sensor pad 12 attached
`across the top or support surface 79 using straps or hands 81;
`and,
`in FIG. 6, a wheelchair 88 is shown having a back
`support 84- and seat 86 with a sensor pad 12 attached across
`the back support using clips 83. Alternatively, or in addition
`to providing a sensor pad on the back support, a sensor pad
`12 can be attached to the seat 86 as shown by broken lines
`in FIG. 6. Monitoring components 13 ofthe system can also
`inciude an earphone jack or receptacle 85 to permit medical
`evaluation simply by inserting a headphone jack or plug (not
`shown) into the receptacle. The sensor pad can be penna-
`nently attached, removably attached or integrally formed
`with the support surface of the medical transport device to
`support any portion of the body of a patient or casualty while
`simultaneously providing vital life function information to
`carenprovider personnel. A sensing pad according to the
`present
`invention can also be positioned directly on a
`hospital operating table or, alternatively,
`the pad can be
`made portable and be placed on an injured soldier’s torso to
`immediately and continuously monitor heartbeat and
`breathing, fluid in the lungs, an obstructed airway, or an
`irregular heartbeat. In this regard, a sensor pad 12 could be
`incorporated into a blanket or an attachable pad 90 formed,
`for example, of a soft rubber tube clamped or glued at
`opposite ends to form seams 91 and filled with a sound
`conducting fluid as shown in FIGS. 7 and 8. Adjustable
`straps 92 or a belt 94 can be attached to pads as shown in
`order to urge the pads into acoustic transfer contact with the
`body and electronics attached to the pads, straps or hell can
`provide processing and output. Individual lengths or seg—
`ments of tubing can be connected together using inserts or
`other mechanisms that create a fluid seal with the tubing
`when adjustable lengths are desired, for example to create a
`tube-like pad that can be wrapped around the neck, torso,
`arms, wrist or legs. Mobile army surgical hospital (MASH)
`units, field hospitals, and disaster response medical sites
`would obviously benefit from a monitor that could be placed
`under or against each patient of a full ward, each of whom
`could be selectively monitored, or have their pad provide an
`audible alarm when breathing or heart beating stops, for
`example. The low-cost of such a sySlCIfl makes it ideally
`suited for naval me