United States Patent
`
`1191
`
`Durkan et al.
`
`[11] Patent Number:
`
`4,462,398
`
`[45] Date of Patent:
`
`Jul. 31, 1984
`
`[54] RESPIRATING GAS SUPPLY METHOD AND
`APPARATUS THEREFOR
`
`[75]
`
`Inventors:
`
`Gerald Durkan, Altoona, Pa.;
`Leonard M. Sieracki, Columbia, Md.
`
`[73] Assignee:
`
`Kircaldie, Randall and McNab,
`Wethersfield, Conn. ; as trustee
`
`[21] Appl. No.: 445,542
`
`[22] Filed:
`
`Dec.3,1982
`
`,
`
`Int. Cl.3 ........................................... .. A61M 16/00
`[51]
`[52] U.S. C1. ........................ ..128/200.14;128/203.12;
`128/204.23; 123/204.24; 128/204.26;
`,
`128/207.18
`[58] Field of Search .................... .. 123/202.22, 203.12,
`128/204.21, 204.22, 204.23, 204.24, 204.25,
`204.26, 204.28, 205.13, 205.17, 205.24, 716, 725,
`200.14,' 207.18; 137/834, 841
`
`[56]
`
`References Cited
`U.S. PATENT DOCUMENTS
`3,097,638
`7/1963 Streimer .
`3,357,428 12/1967 Carlson .
`3,611,178 10/1971 McConnell ................... .. 128/204.23
`3,820,539
`6/1974 Olliver .
`3,863,630 2/1975 Cavallo .
`................... 128/204.28
`3,976,064
`8/1976 Wood et al.
`4,121,579 10/1978 Bird .............................. .. 128/204.25
`4,141,354 2/1979 Ismach .
`4,141,356 2/ 1979 Smargiassi .................... .. 128/204.23
`4,186,737 2/1980 Valenta et al.
`
`4,197,843 .4/1980 Bird .
`.
`4,206,754 6/1980 Cox et al.
`.
`4,215,681
`8/1980 Zalkin et al.
`4,241,732 12/1980 Berindtsson .................. .. 128/204.24
`4,289,126
`9/1981 Seireg et al.
`.
`4,393,869
`7/1983 Boyarsky et al.
`
`............ .. 128/204.23
`
`Primary Examiner—Henry J. Recla
`Attorney, Agent, or Firm—Griffin, Branigan & Butler
`
`[57]
`
`ABSTRACI‘
`
`In various embodiments of a respirating gas supply
`method and apparatus a control circuit (32) responsive
`to a sensor (28) operates valve means (26) to supply
`pulses of respirating gas through a single hose cannula
`(48) to an in vivo respiratory system when negative
`pressure indicative of inspiration is sensed by the sensor
`(28). The control circuit (32) operates the valve (26) to
`communicate the in vivo respiratory system with a
`supply of gas (20) only if the negative pressure sensed
`by the sensor (28) does not occur within a predeter-
`mined yet selectively variable required minimum delay
`interval between successive pulsed applications of gas
`to the in vivo respiratory system. The pulse of gas ap-
`plied to the in vivo respiratory system can be spiked
`pulses or square pulses. Humidifiers, nebulizers, and
`sources of a second gas are provided in accordance with
`various embodiments. Apnea event detection is also
`provided.
`
`11 Claims, 14 Drawing Figures.
`
`. l
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`
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`001
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`PRAXAIR 1010
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`001
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`

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`U.S. Patent
`
`Jul. 31, 1984'”
`
`Sheet 1 of7
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`4,462,398
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`U.S. Patent
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`Jul. 31, 1984
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`Sheet 2 of7
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`4,462,398
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`

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`U.S. Patent
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`Jul. 31, 1984
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`Sheet 3 of7
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`4,462,398_
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`U.S. Patent
`
`Jul. 31, 1984
`
`Sheet 4 of7
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`4,462,398
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`U.S. Patent
`
`Jul. 31, 1984
`
`Sheet 5 of7
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`4,462,398
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`236
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`234
`L9
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`242
`
`INDICATOR
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`

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`U.S. Patent
`
`Jul. 31, 1984'
`
`Sheet6 of7
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`4,462,398 ‘
`
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`U.S. Patent
`
`Jul. 31, 1984
`
`Sheet 7 of 7
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`4,462,398
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`

`
`1
`
`4,462,398
`
`2
`
`RESPIRATING GAS SUPPLY METHOD AND
`APPARATUS THEREFOR
`
`BACKGROUND
`
`systems such as that disclosed in the referenced applica-
`tion for compatability with a single hose cannula.
`Moreover,-it is generally preferable to humidify*re-
`spirating gas before supplying the gas to an in vivo
`respiration system. In some circumstances it is desirable
`to nebulize the-respirating gas with medication before
`supplyingthe gas to the in vivo respiration system.
`Although humidifiers and nebulizers have long been
`used with oxygen supply systems, it is not evident from
`the prior art how a humidifier or nebulizer can be ap-
`propriately utilized with apparatus such as those de-
`scribed in U.S. patent application Ser. No. 210,654,
`especially if' apparatus of that type are used with a single
`hose cannula as discussed above. A great danger in
`utilizing humidifiers and/or nebulizers with either sin-
`gle or double hose cannula systems is the transfer of
`moisture through the hose leading to sensing means
`used to determine the direction of pressure in the in
`vivo system. Moisture in the hose leading to the sensing
`means contaminates the sensor and tends to considera-
`bly shorten thelife of the sensor.
`’ In some situations it may also be desirable to supply
`another gas, such as an anesthetic gas, to in vivo respira-
`torysystem along with the supply of respirating gas. In
`some situations, the dosage of second gas must usually
`be in controlled relation to the amount of respirating gas
`supplied simultaneously therewith. Moreover, a serious
`problem results -in a demand gas-type device when med-
`icating gas is continually applied regardless of the abil-
`ity or inability of the in vivo system to demand the
`respirating gas.
`_
`In view of the foregoing, it is an object of the present
`invention to provide a demand respirating gas supply
`method and apparatus which prevents overoxygenation
`by supplying a fixed volume dose of respirating gas per
`unit time to an in vivo respiratory system.
`An advantage of the invention is the provision of a
`demand respirating gas supply method and apparatus
`which employs asingle hose cannula-, thereby allowing
`pressure sensing and gas supply to be accomplished
`through the same line.
`A further advantage of one embodiment of the inven-
`tion is the provision of a method and apparatus for
`‘supplying spiked shaped pulses of gas at thebeginning
`of an inspiration.
`An advantage of another embodiment of the inven-
`tion is the provision of a method and apparatus for
`supplying square shaped pulses of gas at the beginning
`of an inspiration.
`V
`V
`Yet another advantage of the invention is the provi-
`sion of a compact respirating gas supply apparatus.
`Still another advantage of the invention is the em-
`ployment of humidifiers, nebulizers, and the like with-
`out deleterious impact upon a sensor used in a respirat-
`ing supply gas apparatus.
`»
`SUMMARY .
`
`In various embodiments of a respirating gas supply
`method and apparatus, a control circuit responsiveto a
`sensor operates a valve to supply pulses of respirating
`gas through a single hose cannula to an in vivo respira-
`tory system when negative pressure indicative of inspi-
`ration is sensed by the sensor. The control circuit oper-
`ates’ the valve to communicate the.in-vivorespiratory
`system with a supply of gas only if the negative pressure
`sensed by the sensor does not occur within a predeter-
`mined yet selectively variable required minimum delay
`
`20
`
`1
`
`15
`
`This invention pertains to apparatus and methods for
`providing supplemental respirating gas, such as oxygen,
`to an in vivo respiratory system.
`U.S. patent application Ser. No. 210,654, filed Nov.
`26, 1980 now U.S. Pat. No. 4,414,982 by Gerald P.
`Durkan and commonly assigned herewith, is incorpo-
`rated herein by reference as illustrating a method of
`supplying respirating gas wherein a pulse of gas is sup-
`pliedzto an in vivo respiratory system substantially at
`the beginningof inspiration. U.S. patent application Ser.
`No. 210,654 also discloses a primarily fluidically-
`operated apparatus comprising a demand gas circuit.
`The fluidic apparatus comprising the demand gas cir-
`cuit carries out the method described above and, by
`virtue of the method, is significantly smaller and more
`compact than other demand gas-type apparatus which
`supply respirating gas essentially throughout the dura-
`tion of inspiration. While this lluidic apparatus has
`proven extremely effective in such products as home 25
`oxygen concentrators and oxygen dillusion or delivery
`systems, for example, a further reduction in overall
`apparatus size would further enhance the utility of such
`products.
`1
`i
`'
`Many devices, including those depicted in U.S. pa- 30
`tent application ‘Ser. No. 210,654, are adapted to moni-
`tor or sense pressure direction in an in vivo. respiratory
`system throughout the respiratory cycle and to selec-
`tively supply gas in accordance with the pressure direc-
`tion in the in vivo respiratory system. In this respect, the 35
`in vivo respiratory system creates a.negative pressure
`when an attempt is made to inspire and.create positive
`pressure when an attempt is made_ to exhale. In certain
`instances it is advantageous to. supply pulses of gas such
`as these described in the application Ser. No. 210,654 40
`but in such a manner that a pulse is not necessarily
`supplied for every detection of negativepressureain the
`in vivo respiratory system. For example, should the in
`vivo respiratory system; attempt to inspire .too=fre-
`quently, an;apparatus operating strictly in the manner 45
`described in U.S. patent application Ser. No. .210,654
`would in_some instances cause the in vivo respiratory
`system to overoxygenate. While breathing rate control
`circuits and override circuits have been disclosed in the
`prior art (such as U.S. Pat. Nos. 4,206,754 to Cox and so
`4,141,754 to Ismach, for_.;example) these circuits are
`incompatible with the device described in the refer-
`enced application.
`U.S. patent application Ser. No. 210,654-also illus-
`trates the usage of a “split” or “double hose?’ cannula 55
`which interfaces the in vivo respiration system through
`the nares with the sensing and gas supply elements of
`the apparatus disclosed therein. Although the apparatus
`performs superbly using the double hose cannula, em-
`ployment of a single hose cannula rather than a double 60
`hose cannula would enable both the sensing of the pres-
`sure direction in the in vivo respiratory system and the
`delivery of respirating gas to the in vivo respiratory
`system to be accomplished through the same hose. Sin-
`gle hose cannulae, being less expensive to manufacture 65
`and more convenient for the physician and user, are
`generally more prevalent on the market than double
`hose cannulae. Thus, it would be advantageous to adapt
`
`009
`
`009
`
`

`
`4,462,398
`
`4
`FIG. 7A is a plan view of a fluid amplifier of the
`embodiment of the gas supply apparatus of FIG. 1C;
`FIG. 7B is a graph illustrating'the'- output pressure
`gain curve for the fluidic amplifier shown in FIG. 7A;
`and,
`FIGS. 8A, 8B, and 8C are schematic diagrams show-
`ing differing embodiments of gas supply apparatus
`which detect apnea events and attempt to remedy apnea
`events caused by occlusion of upper airway passages in
`the in vivo respiratory system.
`DETAILED DESCRIPTION OF THE
`DRAWINGS
`
`10
`
`15
`
`3
`interval between successive pulsed application of the
`gas to the in vivo respiratory system.
`~
`In some embodiments, a three-way valve having
`ports connected to the sensor, the gas supply, and the
`single hose cannula is used. In another embodiment, a
`four-way valve facilitates usage of the apparatus in
`conjunction with a humidifier and/or a nebulizer.
`In one embodiment a respirating gas supply apparatus
`has a sensor comprising a biased fluidic amplifier and a
`pressure-to-electric (P/E) switch.
`Apparatus according to theembodiments described
`herein can be operated to supply spiked pulses or square
`pulses of gas depending on whether a flowmeter is
`connected between the supply of gas on the valve.
`The control circuit of the respirating gas supply appa-
`ratus also has means for determining if the in vivo respi-
`ratory system has failed to demand a pulse-of gas after
`the elapse of a predetermined but selectively variable
`maximum time interval. Upon detecting such an apnea
`event, the apparatus activates various indicator or alarm
`means and operates the valve to supply ‘an additional
`pulse or pulses of gas to the in vivo respiratory system.
`Upon the detection of an appropriate apnea event,
`respirating gas supply apparatus according to various
`embodiments supply stimulus to the upper airway pas-
`sages of an in vivo respiratory system in an effort to
`dislodge any occlusion or obstruction in the upper air-
`way passages. In one embodiment the stimulus applied
`is a high pressure pulse of gas. In another embodiment
`an electrical signal is applied to an electromyographic
`electrode (279) positioned in proximity to a nerve con-
`trolling a muscle or organ which may obstruct the
`upper airway passage.
`
`BRIEF DESCRIPTION OF THE DRAWINGS:
`The foregoing and other objects, features and advan-
`tages of the invention will be apparent from the follow-
`ing more particular description of the preferred embodi-
`ments of the invention,'as illustrated in the accompany-
`ing drawings in which like reference characters refer'to
`the same parts throughout different views. The draw-
`ings are not necessarily to scale, emphasis instead being
`placed upon illustrating the principles of the invention.
`FIG. 1A is a schematic diagram showing a gas supply
`apparatus according to an embodiment of the invention
`wherein gas is supplied in a spiked pulse mode;
`FIG. 1B is a schematic diagram showing a gas supply
`apparatus according to an embodiment of the invention
`wherein gas is supplied in a square pulse mode;
`FIG. 1C is a schematic diagram showing a gas supply
`apparatus according to an embodiment of the invention
`wherein sensing means comprises a fluidic amplifier;
`FIG. 2 isa schematic diagram showing a gas supply
`apparatus according to an embodiment of the invention
`wherein supply gas is humidified;
`FIG. 3 is a schematic diagram showing a gas supply
`apparatus according to another embodiment of the in-
`vention wherein supply gas is humidified;
`FIG. 4A is a graph illustrating a spiked pulse method
`of supplying gas according to a mode of the invention;
`FIG. 4B is a graph illustrating a square pulse method
`of supplying gas according to a mode of the invention;
`FIG. 5 is a schematic diagram showing a control
`means according to an embodiment of the invention;
`FIG. 6 is a schematic diagram showing a gas supply
`apparatus according to another embodiment of the in-
`vention wherein-asecond gas is also supplied;
`
`,
`
`'
`
`'
`
`The respirating gas supply system of the “embodiment
`of FIG. 1A comprises a source of gas 20; a tlowmeter
`22; a fluidic capacitance 24; valve means 26; sensing
`means 28; and, control means 32.
`‘
`Source 20 is typically a source of ‘oxygen gas. De-
`» pending upon the particular environment ‘of use, source
`20
`20 may be a portable tank or a wallsupply, for example.
`Source 20 is connected by line 34 to the flowmeter 22.
`As used herein unless otherwise indicated, any‘ fluid 4,
`conveying means, such as a duct, pipe, channel, or othe
`closed fluid conduit, is referred to as a line.
`’
`’
`While the flowmeter 22 may be of any conventional
`type, a ball
`float-type flowmeter manufactured ‘by
`Dwyer is suggested as one acceptable model. The flow-_
`meter illustrated in FIG. 1A comprises a needle valve
`(not shown) which has an inherent resistance FR to the ,
`flow of gas. The flowmeter inherent resistance is depen-
`dent, inter alia, on the dimensions ofthe needle valve
`and the needle orifice. The fiowmeter‘22‘is'connected to
`the capacitance by line 40;”
`I
`'
`"
`Capacitance ‘24 is shown as a‘ tank‘ but in another
`embodiment is merely a relatively long length of tubing.
`As" ‘seen hereinafter, thévoliime of capacitance 24, the
`flowineter inherent resistance“F.R,‘the inherent resis-
`tance VR of ‘the valv'e"26, and the interrelationship
`between theselfactors influence the amplitude of a pulse
`of gas produced by’ the ‘respirating gas supply system of
`FIG.-"IA.
`»
`=
`*
`1
`'
`
`25
`
`30
`
`35
`
`45
`
`50
`
`The "valve means-526 of theembodiment of FIG. 1A is
`a three-way two position solenoid-actuated spool valve
`- having’ ports 26a, ‘26b,*and 26c in its bore. Port 26a is
`connected by line 46 (a single hose) to _.a means 48 for
`supplying gas to an in vivo respiraforyisystem. Al-
`though» the-particular means shown in‘-‘FIG. 1A is a
`single «hose cannula, it should be understood that other
`suitable-devices, such as an endotracheal tube or a hand
`resuscitator, for exampl'e,‘may be employed. The afore-
`said line 40 ultimately conn'ects<ports 26b to the source»
`20. Port 26c is connected by-‘line 50 to the sensing means
`28.
`
`55
`
`65
`
`‘As -shown in the FIG. 1 representation of the valve
`26, the spool of valve 26 is biased to its first position to
`connect port 26a to port 26c so that the cannula 48 (and
`hence in vivo -respiratory system (not shown) including
`nares in which the cannula 48 is inserted) is in fluidic
`communication with the sensing means 28. It should be
`understood that the valve 26 can be operated to move
`the spool to its second position to connect port 26a with
`‘ port 26b so that a pulse of gas is supplied to the in vivo
`respiratory system through the single hose 46. When
`connected-in this manner,'the valve 26 has an inherent
`resistance VR to the flow of gas which is dependent on
`the size of the orifice connecting port 26a to port 26b.
`The valve 26 -is- electrically controlled by control
`means 32 in themanner hereinafter described. While the
`
`010
`
`010
`
`

`
`5
`valve 26 shown in FIG. 1A is of a type manufactured by
`Lee as model LFAA 12003l8H, any comparable model
`can be used.
`
`4,462,398
`
`6
`31 illustrated in FIG. 1C is a conventional P/E switch
`such as that manufactured by Fairchild as Model PSF
`100A. The positive input port of the P/E switch 31 is
`connected to the output port 30d of sensor 30 by line 54
`while the negative input port thereof is open to ambient.
`For the particular sensing means 28 illustrated in FIG.
`1C, the P/E switch 31 should be sensitive enough to
`switch when positive pressure as low as 0.02 cm. of
`water is incident thereon. When P/E switch 31 receives
`such pressure, P/E switch 31 closes a switch 36 as seen
`hereinafter with reference to FIG. 5.
`Referring now again to the embodiment of FIG. 1A,
`it should be understood that other types of sensing
`means 28 may be employed. Those skilled in the art
`recognize that (if operating requirements permit) a
`thermistor system can be utilized, provided the thermis-_
`tor system is made direction sensitive (by utilizing two
`thermistors and appropriate time delay measurement
`circuitry). Ordinarily, however, the flowtype (as op-
`posed to pressure-type) sensitivity of a thermistor pre-
`vents the thermistor from sensing flow rapidly enough
`to facilitate the supply of an oxygen pulse early in inspi-
`ration, such as in the manner taught in U.S. patent appli-
`cation Ser. No. 210,654. In another embodiment, a pres-
`sure transducer functions as the sensing means 28. The
`pressure transducer can be a solid state, a capacitance,
`or an electromechanical (diaphragm-type) transducer,
`depending on the sensitivity required. Transducers pro-
`vide an analog signal and require rather complex elec-
`trical circuitry. A suitable solid state crystal may some-
`day be developed to function as the sensing means 28 in
`accordance with desired sensitivity requirements.
`The respirating gas supply system of FIG. 1B resem-
`bles the system of FIG. 1A but does not have the flow-
`meter 22. As seen hereinafter, the system of FIG. 1A
`produces a spiked pulse of gas whereas the system of
`FIG. 1B produces a square pulse of gas.
`The respirating gas supply system of the embodiment
`of FIG. 2 basically resembles the system of FIG. 1B but,
`rather than employ a three-way valve, utilizes a four-
`way two-position valve 58 as its valve means. The four-
`way valve 58 has four ports in its bore: port 58a con-
`nected by the line 46 to the cannula 48; port 58b con-
`nected by line 42 ultimately to the source 20; port 58c
`connected by line 50 to control port 30b of sensor 28;
`and, port 58d connected by a line 60 to an input of a
`humidifier 62. Valve 58 can be any conventional four-
`way two position valve, such as the solenoid-actuated
`spool valve model 8345E1 manufactured by ASCO. As
`shown in the FIG. 2 representation of valve 58, the
`valve 58 is biased in a first position to connect port 580
`to port 58c so that cannula 48 (and hence the in vivo
`respiratory system) is in fluidic communication with the
`sensor 28. It should be understood that the valve 58 can
`be actuated to a second position to connect port 58b to
`port 58d. When this occurs, gas is supplied through the
`valve 58 and line 60 to the input of humidifier 62.
`Humidifier 62 is a bubble type humidifier, such as the
`model 003-01 humidifier available from Respiratory
`Care, Inc. Humidifier 62 yields a humidified gas flow on
`line 64 connected to the output of the humidifier 62.
`Line 64 connects with a line 46 at point 66. A variable
`resistance 64R on line 64 insures that upon inspiration
`the path of least resistance is through line 46 and the
`value 58 rather than through line 46.
`It should be understood that the apparatus of the
`embodiment of FIG. 2 can be connected in the manner
`
`l0
`
`15
`
`The sensing means 28 of FIG. 1 comprises suitable
`means for sensing a_negative fluidic pressure applied
`along line 50 and for generating an electrical signal in
`accordance with the sensing of the negative fluidic
`pressure. In one embodiment the sensor 28 comprises a
`pressure-to-electric (P/E) switch, such as a Model E
`P/E Switch manufactured by the Dietz Company
`which can sense pressures as low as 0.02 inches (column
`of water). In this embodiment, the negative input port
`of the P/E switch is connected to the line 50 while the
`positive input port is left open to ambient. Large dia-
`phragms used in state-of-the-art P/E switch technol-
`ogy, such as the two inch diameter diaphragm of the
`Dietz Model E P/E, have considerable internal volume
`and hence, for some environments of use, a significantly
`long time response. Many P/E switches must also be
`mounted horizontally to achieve maximum sensitivity, 20
`but mounting the switches horizontally presents an-
`other problem—acceleration sensitivity of the dia-
`phragm.
`The sensing means 28C of FIG. 1C comprises means
`29 for sensing positive fluidic pressure and for generat- 25
`ing an electrical signal in accordance with the sensed
`fluidic pressure, as well as amplification means such as
`fluid amplifier 30. The fluid amplifier 30 depicted in
`FIG. 1C is a biased turbulent proportional amplifier
`shown in more detail in FIG. 7A.
`The biased fluidic amplifier 30 has a power input
`stream 30; two control ports 30b and 30c; and, two
`output ports 30d and 30e. The power stream input port
`30a is connected by the line 44 ultimately to the source
`20. A variable restrictor 52 on line 44 is used to limit the 35
`magnitude of flow and pressure of flow of the input
`stream and thus the sensitivity of the fluidic amplifier
`30. Control port 30b is connected byline 50 to port 26c
`of the valve 26 such that negative pressure in line 50
`(created by inspiration in the in vivo respiratory system) 40
`deflects the power stream to output port 30d. The am-
`plifier 30 is biased such that non-negative pressure in
`line 50 results in the power stream passing through the
`output port 30e.
`The amplifier structure of FIG. 7A illustrates the 45
`biased nature of the amplifier 30. The amplifier 30 is
`configured with an off-set splitter. That is, the power
`input stream 300 is canted so that, absent control signals
`at ports 3% (also labeled C,) and 30c (C1), the output is
`normally biased to the left output port 30e (L). When 50
`negative pressure is applied through port 30b, the out-
`put switches to port 30d. When the negative pressure
`ceases, the output automatically switches back to port
`30e. In a preferred embodiment the amplifier 30 oper-
`ates with a low power supply so that the jet is laminar. 55
`The output pressure gain curve for the fluid amplifier 30
`of FIG. 7A is shown in FIG. 7B.
`.
`
`30
`
`A fluidic amplifier of the type manufactured by Tri-
`Tec, Inc. as Model No. AWl2* functions well as the
`amplifier 30 of FIG. 7A to give a sensitivity to negative 60
`pressures at least as low as 0.02 cm water. It should be
`understood by those skilled in the art that other fluidic
`elements, such as a NOR gate, can be configured with
`the circuitry shown to yield acceptable results.
`In the embodiment of FIG. 1C a pressure-to-electric 65
`(P/E) switch 31 is used as the means for sensing positive
`pressure and for generating an electrical signal in accor-
`dance with the sensed fluidic pressure. The P/E switch
`
`011
`
`011
`
`

`
`4,462,398
`
`8
`The 556 dual timer chip 90 shown in FIG. 5 is a 14 pin
`chip manufactured by National Semiconductor as part
`number LM 556CN. It should be understood that any
`comparable 556 dual timer chip is suitable for the circuit
`of FIG. 5. For the particular chip shown, pins 1-7 cor-
`respond to pins of a first timer in the dual timer while
`pins 8-14 correspond to pins of a second timer. The pins
`are labeled as follows:
`
`7
`of FIG. 1A (that is, with a flowmeter) to operate in a
`spiked pulse mode rather than a square pulse mode.
`The respirating gas supply system of the embodiment
`of FIG. 3 basically resembles the system of FIG. 1B but
`further‘ incorporates the humidifier 62. A line 65 con-
`nects to line 46 at point 67. The line 65 connects the
`point 67 to the input of the humidifier 62. Line 64 from
`the output of the humidifier 62 terminates in a nozzle 68
`of a venturi 70. The venturi 70 is connected on line 46
`intermediate the port 26a of valve 26 and the cannula
`48. A variable resistance 65R on line 65 insures that
`upon inspiration the path of least resistance is through
`the line 46 and the valve 26 rather than through line 65.
`Resistance 65R also serves to control the flow into the
`humidifier 62 through line 65. The venturi 70 shown is
`a type F-4417-10 available from Airlogic, although any
`comparable venturi is suitable. Again, it should be un-
`derstood that the embodiment of FIG. 3 can, if desired,
`incorporate a flowmeter in order to operate in a spiked
`pulse mode.
`It should be understood by those skilled in the art that
`a device for administering medication, such as a nebu-
`lizer, can be connected in the systems of FIGS. 2 or 3 in
`essentially the same respective manners as the humidi-
`fier 62 shown therein.
`The respirating gas supply apparatus of the embodi-
`ment of FIG. 6 basically resembles the embodiment of
`FIG. 1B but further includes means for suppling a sec-
`ond gas to the in vivo respiratory system. The apparatus
`of FIG. 6 further comprises a source 120 of a second gas
`(such as an anesthetic gas, for example), a capacitance
`124; and, second valve means 126. Source 120 is con-
`nected to capacitance 124 by line 134; capacitance 124 is
`connected to the valve means 126 by line 142. The
`apparatus of the embodiment of FIG. 6 can be used, if
`desired, with a humidifier in the manner described
`above with reference to either FIG. 2 or FIG. 3.
`Valve 126 is a two-way two position solenoid-
`actuated spool valve having port 126a and 126b in its
`bore. The central spool of valve 126 is biased in a first
`position as shown in FIG. 6 so that ports 126a and 126b
`are not communicating. Port 126b of valve 126 is con-
`nected by line 144 to a point 146 where line 144 joins
`line 46. A variable resistance 147 on line 144 insures that
`upon inspiration the path of least resistance is through
`the line 46 and valve 26 rather than through line 144.
`The solenoid valve 126 is electrically connected by lines
`L3’ and L3 to the control means 32. In other embodi-
`ments the solenoid valve is mechanically connected to a
`control means.
`The control means 32 of the embodiment of FIG. 5 is
`suitable for use with apparatus constructed in accor-
`dance with any of the foregoing embodiments. Control
`means 32 is a circuit comprising four NAND gates (72,
`74, 76, and 78); four NOR gates (80, 82, 84, and 86);
`three transistors (T1, T2, and T3); a 555 timer chip 88;
`a 556 dual timer chip 90; LEDs 92 and 94; piezo electric
`member 96; and, various resistances and capacitances as
`hereinafter designated.
`As used with reference to FIG. 5, the notation “LX”
`denotes an electrical line (as opposed to a fluidic line)
`where X is‘an appropriate reference number. For exam-
`ple, controller 32 includes a line L1 connected to a high
`DC voltage supply (not shown) and line L2 connected
`to a low DC voltage supply (also not shown). The po-
`tential difference across L1 and L2 is between 12 and 15
`volts DC.
`
`10
`
`15
`
`20
`
`25
`
`30
`
`35
`
`45
`
`50
`
`55
`
`60
`
`65
`
`PIN DESCRIPTION FOR 556 CHIP
`
`
`
` DESCRIPTION TIMER 1 TIMER Z
`
`discharge
`1
`13
`threshold
`2
`12
`control voltage
`3
`ll
`reset
`4
`10
`output
`5
`9
`trigger
`6
`8
`ground
`7
`
`operating voltage 14
`
`The pin connections for,,the first timer of the 556 dual
`timer 90 are as follows: Pins 1 and 2 are connected to
`line L2 through a series combination of resistor R1 and
`a 100K variable potential resistance R2. Pins 1 and 2 are
`also connected to line L2 through capacitance C1. Pin 3
`is connected to line L2 through capacitor C2. Pin 4 is
`connected directly to line L1. Pin 5 is connected to the
`base of transistor T1 through resistor R3. Pin 5 is also
`connected to the anode of LED 92 (the cathode of
`LED 92 being connected through resistor R4 to the line
`L2). Pin 6 is connected through capacitor C3 to the
`output terminal of NOR 80. Pin 6 is also connected to
`line L1 through the resistor R14 and to line L2 through
`the resistor R15. Pin 7 is connected directly to line L2.
`The pin connections for the second timer of the 556
`dual timer 90 are as follows: Pin 8 is connected through
`capacitor C4 to the output terminal of NOR 84, as well
`as to line L1 through the resistor R16 and to line L2
`through the resistor R17. Pin 9 is connected to both
`input terminals of NAND 74. Pin 10 is connected di-
`rectly to line L1 and to a point 102 discussed hereinaf-
`ter. Pin 11 is connected through capacitance C5 to line
`L2. Pins 12 and 13 are connected to line L1 through a
`series combination of resistor R5 and a 100K variable
`potential resistor R6. Pins 12 and 13 are also connected
`to line L2 through capacitance C6. Pin 14 is connected
`directly to line L1.
`The 555 timer chip 88 shown in FIG. 5 is an eight pin
`chip manufactured by National Semiconductor as part
`number LM 555CN. It should be understood that any
`comparable 555 chip is suitable for the circuitry of FIG.
`5. For the particular chip shown the pins are labeled as
`follows:
`
`
`PIN
`DESCRIPTION
`ground
`trigger
`output
`reset
`control
`threshold
`discharge
`operating voltage
`
`®\IO\UI-filalffilfi-'
`
`The pin connections for the 555 timer chip 88 are as
`follows: Pin 1 is connected directly to line L2. Pin 2 is
`connected to the output of NOR 82 and to the base of
`
`012
`
`012
`
`

`
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`
`10
`
`15
`
`20
`
`25
`
`30
`
`35
`
`9
`transistor T2. Pin 3 is connected to both inputs of NOR
`86 and to a point 98. Pin 4 is directly connected to line
`L]. Pin Sis connected to line L2 through capacitor C7.
`Pins 6 and 7 are connected to line L2 through capaci-
`tance C8. Pins 6 and 7 are also connected to line L1
`through a series combination of resistances, the combi-
`nation including a resistor R7 and anyone of a group of
`parallel-arranged resistances such as resistances Ra, Rb,
`and Rc .
`.
`.
`. Which of the parallel-arranged resistances
`is used depends on the manual positioning of a switch
`100 as described hereinafter. Pins 6 and 7 "are also con-
`nected to the emitter of transistor T2. Pin 8 is connected
`directly to the line L1.
`'
`'
`NAND 72 has a first input terminal 72a connected to
`line L1 through resistance R8 and connected to L2
`through the switch 36. A second input terminal 72b of
`the NAND 72 is connected to the output terminal of
`NAND 74. The output terminal of NAND 72 is con-
`nected to a first input terminal 80a of NOR 80, aswell
`as to both input terminals of the following: NOR 82,
`NOR 84, and NAND 76. The first input terminal 80a of
`NOR 80 is also connected to a point 104 intermediate
`the output terminal of NOR 86 and the anode of LED
`94. The second input terminal 80b of NOR 80 is con-
`nected to line L2 through resistor R9. The lines L4, L5,
`L6, and L7 shown in FIG. 5 are connected to further
`devices, such as instrumentation which, unless other-
`wise noted herein, do not form part of the present in-
`vention.
`Transistor T1 is a NPN transistor, such as the type
`available from GE as part GE-66A. The emitter of
`transistor T1 is connected'dire‘ctly to line L2. The‘ col-
`lector of transistor T18 is isolated from line L2 by a diode
`D1 (IN 4005) and is connected‘ to the positive terminal
`of appropriate valve means (such as valve 26 or valve
`58) by line L3.‘Line L8 is connected to the negative (or
`ground) terminal of the appropri