US3768468A - Ventilators - Google Patents
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- US3768468A US3768468A US00106960A US3768468DA US3768468A US 3768468 A US3768468 A US 3768468A US 00106960 A US00106960 A US 00106960A US 3768468D A US3768468D A US 3768468DA US 3768468 A US3768468 A US 3768468A
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- 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
- A61B5/7242—Details of waveform analysis using integration
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- 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
- A61B5/091—Measuring volume of inspired or expired gases, e.g. to determine lung capacity
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- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61M—DEVICES FOR INTRODUCING MEDIA INTO, OR ONTO, THE BODY; DEVICES FOR TRANSDUCING BODY MEDIA OR FOR TAKING MEDIA FROM THE BODY; DEVICES FOR PRODUCING OR ENDING SLEEP OR STUPOR
- A61M16/00—Devices for influencing the respiratory system of patients by gas treatment, e.g. mouth-to-mouth respiration; Tracheal tubes
- A61M16/0051—Devices for influencing the respiratory system of patients by gas treatment, e.g. mouth-to-mouth respiration; Tracheal tubes with alarm devices
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- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61M—DEVICES FOR INTRODUCING MEDIA INTO, OR ONTO, THE BODY; DEVICES FOR TRANSDUCING BODY MEDIA OR FOR TAKING MEDIA FROM THE BODY; DEVICES FOR PRODUCING OR ENDING SLEEP OR STUPOR
- A61M16/00—Devices for influencing the respiratory system of patients by gas treatment, e.g. mouth-to-mouth respiration; Tracheal tubes
- A61M16/021—Devices for influencing the respiratory system of patients by gas treatment, e.g. mouth-to-mouth respiration; Tracheal tubes operated by electrical means
- A61M16/022—Control means therefor
- A61M16/024—Control means therefor including calculation means, e.g. using a processor
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- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
- A61B2560/00—Constructional details of operational features of apparatus; Accessories for medical measuring apparatus
- A61B2560/02—Operational features
- A61B2560/0266—Operational features for monitoring or limiting apparatus function
- A61B2560/0276—Determining malfunction
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
- Y10S—TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y10S137/00—Fluid handling
- Y10S137/908—Respirator control
Definitions
- the present invention aims at providing a lung ventilator in which the volume of gas supplied to the patient during each inspiratory phase of the respiratory cycle can be chosen and adjusted, irrespective of any variations in the rate of flow of gas to the patient.
- gas in this specification is usually meant a mixture of gases, although there might be occasions in practice in which a pure gas, such as oxygen, might be used.
- the present invention provides a lung ventilator which is as claimed in the appended claims.
- volume-cycled ventilator There are three main types of lung ventilators: volume-cycled, time-cycled and pressure-cycled. Of these the volume-cycled ventilator is the type preferred for long-term ventilation, as is used in intensive care units. However, despite its popularity, the volumecycled ventilator has disadvantages.
- the main advantage claimed for volume cycling is that the ventilator will continue to deliver a chosen volume of gas regardless of changes in compliance of the patient or resistance of the airways. However this is only partly true, in that the actual volume of gas may be less, sometimes considerably so, than the volume which the ventilator indicates as having been supplied to the patient. This discrepancy may be caused by leaks in the various connections and by incorrectly set safety valves or other components.
- the desired gas mixture passes from the mixer 2 to a device 4 which determines the flow pattern. For example, it may be desirable to maintain a constant flow rate throughout the inspiratory phase. Alternatively it may be desirable for the flow rate to be initially quite high, decreasing after a time to a chosen rate which continues until the end of that inspiratory phase of the respiratory cycle. Other flow patterns may also be required.
- the gas leaving the pattern generator 4 is shown as passing to a separate device 6 for controlling the flow, al-
- the gas then passes through a valve 8 which is biassed to be open during the inspiratory phase, the valve 8 being controlled by a device 10.
- the gas next passes to a sensor 12, which is preferably of the type which develops a signal, preferably electrical of which the frequency is proportional to the gas flow rate, each time a unit volume of gas has passed through the sensor.
- the signals pass to an integrator or pulse counter 14.
- samples of the gas may be passed into an analyser 18 adapted to display the percentage of oxygen in the gas flowing along the airway 20. This indicator acts as a check on the correct operation of the mixer 2.
- the valve 16 is preferably of the two-position, fiveport type although other multi-port valves could be used. Two of the ports go to the patient (not shown); one of the ports is in communication with the airway 20; another is in communication with an exhaust line 22, and the fifth in communication with a manual rebreathing device 24. Gas expired by the patient and passing up the line 22 flows through a second sensor 26 which, similarly to sensor 12, passes to a second integrator or pulse counter 27 signals indicative of the volumetric flow through it.
- Gas leaving sensor 26 passes through an expiratory valve 28 which is controlled by the pressure of gas in a control line 30, the valve acting as a lightly loaded non-return valve when the pressure in line 30 is below a chosen value, and being forcibly closed to prevent further exhalation when the pressure is above this value.
- the pressure in control line 30 is derived from the main airway 20, and an extension 32 of the control line also passes to the valve 16 to bias it to the position in which the valve is in its automatic position.
- the valve 16 is movable manually or automatically from this position to the manual position in which the device 24 is able to supply gas to the patient, with airway 20 being blocked.
- the ventilator may be designed so that upon failure of the oxygen supplied to the mixer 2, the valve 16 is automatically switched over to its manual position and an alarm signal generated to alert an operator of the ventilator to the fact that it is operating in the manual mode.
- the means by which this canbe effected do not form part of the subject-matter of this application and so will not be described herein in greater detail.
- valve 34 Inserted in the control line 30 is a valve 34 also controlled by device 10.
- the change in pressure in line 30, as a result of actuation of valve 34, is used to operate a pressure-sensitive switch 39 connected to a timer 40.
- the integrator 14 supplies a signal, indicative of the volume passing through the sensor 12, to a comparator 36, which receives a similar signal from a preset volume signal generator 38 which the operator can adjust.
- the comparator 36 supplies an output signal to the control device 10, and is arranged to supply this signal when the measured volume of gas passing through the sensor 12 is equal to the volume preset by device 38.
- control device 10 Operation of control device 10 is arranged to cause switch 39 to supply a signal to an expiratory timer 40 which then supplies a signal resetting the comparator 36 and the valve 8 when a chosen time interval has elapsed since operation of the control device 10.
- the integrator 14 is also connected to a voltmeter 46 operating as a tidal volume indicator. During the inspiratory phase of the breathing cycle the integrator 14 increments the reading of voltmeter 46, which reading remains static during the ensuing expiratory phase. At the changeover to the next inspiratory phase the integrator 14 and the meter 46 are reset to zero (by means which is not shown).
- the integrator 27 is similarly connected to a second voltmeter 42 acting as a minute volume indicator, which is connected in turn to an alarm device 44.
- the charge sensed at the appropriate terminal of meter 42 is continually discharged through a leak resistor (not shown).
- the meter 42 thus settles at a reading determined by the constant leak being balanced (somewhat inexactly) by the pulsiform additions from integrator 27, the meter being damped appropriately. This reading is a measure of the minute volume. Too low a reading, caused as by the patient ceasing to breathe, or the supply of gas falling excessively or ceasing, causes the alarm 44 to be triggered. This happens also when the reading becomes excessive, indicating over-ventilation of the patient.
- all the components of the ventilator are preferably enclosed in a common housing from which project the ends of the various conduits and airways, and also the control knobs for the adjustable components.
- the faces of the minute volume indicator and tidal volume indicator are also visible to the operator, so that he has all the necessary indications of the working of the ventilator without being concerned about its internal arrangements.
- the ventilator operates as follows:
- the mixer 2 supplies to the pattern generator 4 gas having a chosen amount of oxygen. This may range in steps from about 20 percent oxygen to 100 percent oxygen.
- the pattern generator may provide for continuous adjustment of the flow rate pattern or it may similarly be able to provide any one of a discrete number of patterns.
- the flow rate device may provide for any one of, say, six different flow rates to be provided, spanning the range, say, from to 70 litres per minute, although conceivably this could be adjustable continuously over the same range or any other range considered desirable.
- valve 8 is biassed open, as by a solenoid in device 10 operating both valves 8 and 34, as indicated by the broken line 48.
- the gas passing through the valve 8 flows directly through the sensor 12 and the respective passages in the valve 16.
- valve 28 is biassed closed by the pressure in control line 30, so that no flow passes from the patient through the sensor 26.
- the comparator 36 When the signals from the integrator 14 indicate that the volume of gas which has passed through the sensor 12 is equal to the desired volume, then the comparator 36 generates a signal to vary the position of the control device 10. This device 10 is then effective to close the valve 8 and simultaneously open the valve 34, so that the pressure of the gas in line 30 decreases and allows the expiratory valve 28 to open to permit the patient to expire. This pressure rise operates switch 39 and starts the expiratory timer 40 to set the length of the expiratory phase of the respiratory cycle. When this preset time has lapsed, the timer 40 supplies a signal to the comparator to reset it. The control device 10 is also reset, causing the expiratory valve to be closed and the inspiratory valve 8 to be opened, so that the next respiratory cycle is started.
- the essential components of the ventilator which give it the desired and novel degree of flexibility are the sensor 12', the integrator 14 for measuring the volume of gas supplied to the patient; the comparator 36; the volume control 38, and the control device 10 and its associated valve 8 in the airway to the patient.
- the valve 16 in the event of failure of electrical supplies or pressure of the gas supplied to the ventilator, the valve 16 is arranged to be switched automatically to its manual mode.
- the device 24 may be a rebreathing bag, or self-filling bellows or equivalent device, by means of which the patient may be inflated manually and allowed to expire naturally, as is well-known.
- the present invention provides a lung ventilator in which the flow of gas to the patient may be adjusted to have a desired pattern during each inspiratory phase, while the tidal volume can be preset to a chosen amount irrespective of any variations in the flow rate or pattern.
- a lung ventilator adapted to control the volume of respirable gas supplied to a patient irrespective of the duration of the inspiratory phase of the patients respiratory cycle, of the patients airway pressure, or of variations in the rate at which gas flows to the patient, including an inhalation passageway connected at one end to a supply of pressurized respirable gas, and at the other end to the patient; an exhalation passageway connected to the patient; a gas flow control valve in said inhalation passageway; a gas flow sensitive transducer in said inhalation passageway and said exhalation passageway adapted to generate signals of which the frequency is proportional to the gas flow rate; means integrating said flow rate signals to produce a signal which is a measure of the volume of gas flowing therethrough; means for closing the said valve when the said integrated signal from said gas flow sensitive transducer in said inhalation passageway reaches a chosen value, and means for reopening the valve and rendering the transducer effective at the beginning of the next inspiratory phase.
- a lung ventilator as claimed in claim 1 including a two-position, multiple-port valve movable between a manual and an automatic position, the valve having two of its ports connected to the inspiration and expiration passageways of the ventilator, two ports adapted to be connected to a patient, and the remaining port or ports adapted to be connected to a manual rebreathing device.
- a lung ventilator as claimed in claim 1 in which the signals corresponding to the inspiratory volume flow are fed to an integrator of which the output is fed to a comparator for comparison with like signals corresponding to the desired volume flow, equalisation of the two signals being effective to cause the comparator to generate a changeover signal stopping the inspiratory flow and allowing the expiratory flow to start.
- a lung ventilator as claimed in claim 4 including a tidal volume indicator connected to the inspiratory flow integrator.
- a lung ventilator as claimed in claim 1 in which couplied to the inspiratory flow passageway is a meter for indicating the oxygen content of the gas supplied to the outlet of the ventilator.
Abstract
A lung ventilator in which the volume of respirable gas passing to the patient per unit time is continuously measured and the flow stopped, to mark the end of the inspiratory phase and the start of the expiratory phase, when a chosen volume has passed through the meter.
Description
United States Patent Cox Oct. 30, 1973 [54] VENTILATORS 3,530,872 9/1970 Arp 128/l45.6 X r 3,101,708 8/1963 Perry et al. 128/145.5 lnvemo Lawrence Alfred 3,357,428 12/1967 Carlson l28/l45.8 North Weald, England 3,523,527 8/1970 Foster..... 128/145.8 x [73] Assignee: The British Oxygen Company 1,169,995 2/1916 Prindle.... 128/1456 7 Limited, London, England 3,033,196 5/1962 Hay 128/145.8 3,191,595 6/1965 Wilson 128/1455 Flled: Jan. 18, 19 1 3,114,365 12/1963 Franz 128/145 211 App]. No.2 106,960
Primary Examiner-R1chard A, Gaudet Assistant Examiner-G. F. Dunne Foreign Application Data Attorney-Dennison, Dennison, Townshend &
Jan. 21, 1970 United Kingdom 2938/70 M rme 52 us. 01. 128/1458, 137/63 R [57] ABSTRACT [51] Int. Cl. A6lm 16/00 A l t h th I f M [58] Field 61 Search 128/l45.8, 142-1423, z f '5 f 128/1424 145 R 1455,1456, 145.7, 188' gas passmg o e pa len per um mm 18 con lnuousy DIG 17, 137/68 R mea ure 1 and thc flow stopped, to mark the 0nd of the msplratory phase and the start of the explratory [56] References Cited 51122:, when a chosen volume has passed through the UNITED STATES PATENTS 3,033,195 5 1962 Gilroy 128/145.8 10 Clam, 1 D'awmg 3,628,042 12 1971 Jacobus 3,633,576 1/1972 Gorsuch 128/145.8
The present invention aims at providing a lung ventilator in which the volume of gas supplied to the patient during each inspiratory phase of the respiratory cycle can be chosen and adjusted, irrespective of any variations in the rate of flow of gas to the patient.
By gas in this specification is usually meant a mixture of gases, although there might be occasions in practice in which a pure gas, such as oxygen, might be used.
Accordingly the present invention provides a lung ventilator which is as claimed in the appended claims.
The present invention will now be described by way of example with reference to the accompanying drawing, which is a schema of one form of lung ventilator of the present invention.
There are three main types of lung ventilators: volume-cycled, time-cycled and pressure-cycled. Of these the volume-cycled ventilator is the type preferred for long-term ventilation, as is used in intensive care units. However, despite its popularity, the volumecycled ventilator has disadvantages.
The main advantage claimed for volume cycling is that the ventilator will continue to deliver a chosen volume of gas regardless of changes in compliance of the patient or resistance of the airways. However this is only partly true, in that the actual volume of gas may be less, sometimes considerably so, than the volume which the ventilator indicates as having been supplied to the patient. This discrepancy may be caused by leaks in the various connections and by incorrectly set safety valves or other components.
Conventional volume-cycled ventilators normally use a fixed-volume device, such as bellows or a piston. With these ventilators, the pattern of inspiratory flow is generally fixed, or is adjustable only to a very limited extent. In other words, the limitations imposed by bellows or a piston (with their associated driving mechanisms) restricts the users ability to alter the flow pattern at will, even though the inspiration/expiration ratio can usually be varied. It is well known that the inspiratory and expiratory flow pattern in mechanical ventilation can affect the efficiency of pulmonary gas exchange, even though the optimum ventilatory flow pattern has yet to be defined. Thus the ability to be able to vary the rate of flow throughout the inspiratory phase of the respiratory cycle, and at the same-time to choose the volume to be cycled, would be a considerable advantage, which is offered by apparatus of the present invention. v
This includes a mixer 2 to which is connected separate pipe lines for supplying oxygen and air or any other combination of respirable gases. The desired gas mixture passes from the mixer 2 to a device 4 which determines the flow pattern. For example, it may be desirable to maintain a constant flow rate throughout the inspiratory phase. Alternatively it may be desirable for the flow rate to be initially quite high, decreasing after a time to a chosen rate which continues until the end of that inspiratory phase of the respiratory cycle. Other flow patterns may also be required. For convenience, the gas leaving the pattern generator 4 is shown as passing to a separate device 6 for controlling the flow, al-
though in practice the devices 4 and 6 could be combined into a single device determining both the flow rate and the flow pattern. The gas then passes through a valve 8 which is biassed to be open during the inspiratory phase, the valve 8 being controlled by a device 10.
The gas next passes to a sensor 12, which is preferably of the type which develops a signal, preferably electrical of which the frequency is proportional to the gas flow rate, each time a unit volume of gas has passed through the sensor. The signals pass to an integrator or pulse counter 14.
On its way to a valve 16 samples of the gas may be passed into an analyser 18 adapted to display the percentage of oxygen in the gas flowing along the airway 20. This indicator acts as a check on the correct operation of the mixer 2.
The valve 16 is preferably of the two-position, fiveport type although other multi-port valves could be used. Two of the ports go to the patient (not shown); one of the ports is in communication with the airway 20; another is in communication with an exhaust line 22, and the fifth in communication with a manual rebreathing device 24. Gas expired by the patient and passing up the line 22 flows through a second sensor 26 which, similarly to sensor 12, passes to a second integrator or pulse counter 27 signals indicative of the volumetric flow through it.
The pressure in control line 30 is derived from the main airway 20, and an extension 32 of the control line also passes to the valve 16 to bias it to the position in which the valve is in its automatic position. The valve 16 is movable manually or automatically from this position to the manual position in which the device 24 is able to supply gas to the patient, with airway 20 being blocked. Although this is not shown in the drawing, or described in great detail in the specification, the ventilator may be designed so that upon failure of the oxygen supplied to the mixer 2, the valve 16 is automatically switched over to its manual position and an alarm signal generated to alert an operator of the ventilator to the fact that it is operating in the manual mode. However the means by which this canbe effected do not form part of the subject-matter of this application and so will not be described herein in greater detail.
Inserted in the control line 30 is a valve 34 also controlled by device 10. The change in pressure in line 30, as a result of actuation of valve 34, is used to operate a pressure-sensitive switch 39 connected to a timer 40.
The integrator 14 supplies a signal, indicative of the volume passing through the sensor 12, to a comparator 36, which receives a similar signal from a preset volume signal generator 38 which the operator can adjust. The comparator 36 supplies an output signal to the control device 10, and is arranged to supply this signal when the measured volume of gas passing through the sensor 12 is equal to the volume preset by device 38.
Operation of control device 10 is arranged to cause switch 39 to supply a signal to an expiratory timer 40 which then supplies a signal resetting the comparator 36 and the valve 8 when a chosen time interval has elapsed since operation of the control device 10.
The integrator 14 is also connected to a voltmeter 46 operating as a tidal volume indicator. During the inspiratory phase of the breathing cycle the integrator 14 increments the reading of voltmeter 46, which reading remains static during the ensuing expiratory phase. At the changeover to the next inspiratory phase the integrator 14 and the meter 46 are reset to zero (by means which is not shown).
The integrator 27 is similarly connected to a second voltmeter 42 acting as a minute volume indicator, which is connected in turn to an alarm device 44. The charge sensed at the appropriate terminal of meter 42 is continually discharged through a leak resistor (not shown). The meter 42 thus settles at a reading determined by the constant leak being balanced (somewhat inexactly) by the pulsiform additions from integrator 27, the meter being damped appropriately. This reading is a measure of the minute volume. Too low a reading, caused as by the patient ceasing to breathe, or the supply of gas falling excessively or ceasing, causes the alarm 44 to be triggered. This happens also when the reading becomes excessive, indicating over-ventilation of the patient.
For convenience, all the components of the ventilator are preferably enclosed in a common housing from which project the ends of the various conduits and airways, and also the control knobs for the adjustable components. The faces of the minute volume indicator and tidal volume indicator are also visible to the operator, so that he has all the necessary indications of the working of the ventilator without being concerned about its internal arrangements.
The ventilator operates as follows:
The mixer 2 supplies to the pattern generator 4 gas having a chosen amount of oxygen. This may range in steps from about 20 percent oxygen to 100 percent oxygen. The pattern generator may provide for continuous adjustment of the flow rate pattern or it may similarly be able to provide any one of a discrete number of patterns. Similarly the flow rate device may provide for any one of, say, six different flow rates to be provided, spanning the range, say, from to 70 litres per minute, although conceivably this could be adjustable continuously over the same range or any other range considered desirable.
During the inspiratory phase the valve 8 is biassed open, as by a solenoid in device 10 operating both valves 8 and 34, as indicated by the broken line 48. When in the automatic mode, the gas passing through the valve 8 flows directly through the sensor 12 and the respective passages in the valve 16.
During this phase, the valve 28 is biassed closed by the pressure in control line 30, so that no flow passes from the patient through the sensor 26.
When the signals from the integrator 14 indicate that the volume of gas which has passed through the sensor 12 is equal to the desired volume, then the comparator 36 generates a signal to vary the position of the control device 10. This device 10 is then effective to close the valve 8 and simultaneously open the valve 34, so that the pressure of the gas in line 30 decreases and allows the expiratory valve 28 to open to permit the patient to expire. This pressure rise operates switch 39 and starts the expiratory timer 40 to set the length of the expiratory phase of the respiratory cycle. When this preset time has lapsed, the timer 40 supplies a signal to the comparator to reset it. The control device 10 is also reset, causing the expiratory valve to be closed and the inspiratory valve 8 to be opened, so that the next respiratory cycle is started.
It will be appreciated that the essential components of the ventilator which give it the desired and novel degree of flexibility are the sensor 12', the integrator 14 for measuring the volume of gas supplied to the patient; the comparator 36; the volume control 38, and the control device 10 and its associated valve 8 in the airway to the patient.
As has been mentioned briefly above, in the event of failure of electrical supplies or pressure of the gas supplied to the ventilator, the valve 16 is arranged to be switched automatically to its manual mode. The device 24 may be a rebreathing bag, or self-filling bellows or equivalent device, by means of which the patient may be inflated manually and allowed to expire naturally, as is well-known.
It is usual in lung ventilators to incorporate a safety valve to control the pressure of gas in the system to ensure that the patient is not over-inflated should part of the ventilator malfunction. The safety valve is not shown in the drawing, for clarity, but it would normally be positioned upstream of the sensor 12 so that any gas passing to the atmosphere through the safety valve would not be registered falsely as gas supplied to the patient.
It will thus be seen that the present invention provides a lung ventilator in which the flow of gas to the patient may be adjusted to have a desired pattern during each inspiratory phase, while the tidal volume can be preset to a chosen amount irrespective of any variations in the flow rate or pattern.
The manner in which many components of the illustrated system are actuated has been shown only by way of example. Thus some of the pneumatically operated or biassed components could be actuated mechanically or electromechanically while still being in accordance with the invention.
I claim:
1. A lung ventilator adapted to control the volume of respirable gas supplied to a patient irrespective of the duration of the inspiratory phase of the patients respiratory cycle, of the patients airway pressure, or of variations in the rate at which gas flows to the patient, including an inhalation passageway connected at one end to a supply of pressurized respirable gas, and at the other end to the patient; an exhalation passageway connected to the patient; a gas flow control valve in said inhalation passageway; a gas flow sensitive transducer in said inhalation passageway and said exhalation passageway adapted to generate signals of which the frequency is proportional to the gas flow rate; means integrating said flow rate signals to produce a signal which is a measure of the volume of gas flowing therethrough; means for closing the said valve when the said integrated signal from said gas flow sensitive transducer in said inhalation passageway reaches a chosen value, and means for reopening the valve and rendering the transducer effective at the beginning of the next inspiratory phase.
2. A lung ventilator as claimed in claim 1, including a two-position, multiple-port valve movable between a manual and an automatic position, the valve having two of its ports connected to the inspiration and expiration passageways of the ventilator, two ports adapted to be connected to a patient, and the remaining port or ports adapted to be connected to a manual rebreathing device.
3. A lung ventilator as claimed in claim 2, in which the said multiple-port valve is connected to means for displacing it into the manual position when the pressure of oxygen or other selected gas supplied to the ventilator falls below a chosen minimum value.
4. A lung ventilator as claimed in claim 1, in which the signals corresponding to the inspiratory volume flow are fed to an integrator of which the output is fed to a comparator for comparison with like signals corresponding to the desired volume flow, equalisation of the two signals being effective to cause the comparator to generate a changeover signal stopping the inspiratory flow and allowing the expiratory flow to start.
5. A lung ventilator as claimed in claim 4, in which the outlet of the comparator is connected to a device controlling both a valve in the inspiratory flow passageway and an auxiliary valve controlling the position of a valve in the expiratory flow passageway.
6. A lung ventilator as claimed in claim 4, in which operation of the control device is adapted to start a timer when the comparator generates the said changeover signal and which, after a chosen time has elapsed, causes the comparator to be reset and the inspiratory valve to be opened.
7. A lung ventilator as claimed in claim 1, including a minute volume indicator connected to said exhalation integrating means.
8. A lung ventilator as claimed in claim 7, in which connected to the minute volume indicator is an alarm device adapted to operate when the minute volume goes beyond chosen minimum and maximum values.
9. A lung ventilator as claimed in claim 4, including a tidal volume indicator connected to the inspiratory flow integrator.
10. A lung ventilator as claimed in claim 1, in which couplied to the inspiratory flow passageway is a meter for indicating the oxygen content of the gas supplied to the outlet of the ventilator.
Claims (10)
1. A lung ventilator adapted to control the volume of respirable gas supplied to a patient irrespective of the duration of the inspiratory phase of the patient''s respiratory cycle, of the patient''s airway pressure, or of variations in the rate at which gas flows to the patient, including an inhalation passageway connected at one end to a supply of pressurized respirable gas, and at the other end to the patient; an exhalation passageway connected to the patient; a gas flow control valve in said inhalation passageway; a gas flow sensitive transducer in said inhalation passageway and said exhalation passageway adapted to generate signals of which the frequency is proportional to the gas flow rate; means integrating said flow rate signals to produce a signal which is a measure of the volume of gas flowing therethrough; means for closing the said valve when the said integrated signal from said gas flow sensitive transducer in said inhalation passageway reaches a chosen value, and means for reopening the valve and rendering the transducer effective at the beginning of the next inspiratory phase.
2. A lung ventilator as claimed in claim 1, including a two-position, multiple-port valve movable between a ''manual'' and an ''automatic'' position, the valve having two of its ports connected to the inspiration and expiration passageways of the ventilator, two ports adapted to be connected to a patient, and the remaining port or ports adapted to be connected to a manual rebreathing device.
3. A lung ventilator as claimed in claim 2, in which the said multiple-port valve is connected to means for displacing it into the manual position when the pressure of oxygen or other selected gas supplied to the ventilator falls below a chosen minimum value.
4. A lung ventilator as claimed in claim 1, in which the signals corresponding to the inspiratory volume flow are fed to an integrator of which the output is fed to a comparator for comparison with like signals corresponding to the desired volume flow, equalisation of the two signals being effective to cause the comparator to generate a changeover signal stopping the inspiratory flow and allowing the expiratory flow to start.
5. A lung ventilator as claimed in claim 4, in which the outlet of the comparator is connected to a device controlling both a valve in the inspiratory flow passageway and aN auxiliary valve controlling the position of a valve in the expiratory flow passageway.
6. A lung ventilator as claimed in claim 4, in which operation of the control device is adapted to start a timer when the comparator generates the said changeover signal and which, after a chosen time has elapsed, causes the comparator to be reset and the inspiratory valve to be opened.
7. A lung ventilator as claimed in claim 1, including a minute volume indicator connected to said exhalation integrating means.
8. A lung ventilator as claimed in claim 7, in which connected to the minute volume indicator is an alarm device adapted to operate when the minute volume goes beyond chosen minimum and maximum values.
9. A lung ventilator as claimed in claim 4, including a tidal volume indicator connected to the inspiratory flow integrator.
10. A lung ventilator as claimed in claim 1, in which couplied to the inspiratory flow passageway is a meter for indicating the oxygen content of the gas supplied to the outlet of the ventilator.
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
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GB293870A GB1338226A (en) | 1970-01-21 | 1970-01-21 | Lung ventilators |
Publications (1)
Publication Number | Publication Date |
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US3768468A true US3768468A (en) | 1973-10-30 |
Family
ID=9748884
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US00106960A Expired - Lifetime US3768468A (en) | 1970-01-21 | 1971-01-18 | Ventilators |
Country Status (8)
Country | Link |
---|---|
US (1) | US3768468A (en) |
JP (1) | JPS5223198B1 (en) |
DE (1) | DE2102837A1 (en) |
DK (1) | DK134634B (en) |
FR (1) | FR2075764A5 (en) |
GB (1) | GB1338226A (en) |
NL (1) | NL7100834A (en) |
SE (1) | SE370495B (en) |
Cited By (35)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3923056A (en) * | 1974-06-19 | 1975-12-02 | Gen Electric | Compliance compensation for electronically controlled volume respirator systems |
US3946729A (en) * | 1974-10-17 | 1976-03-30 | Hewlett-Packard Company | Ventilator patient monitor |
US3976065A (en) * | 1975-03-10 | 1976-08-24 | Gerald Durkan | Digital fluidic ventilator |
US4206754A (en) * | 1976-06-02 | 1980-06-10 | Boc Limited | Lung ventilators |
US4241732A (en) * | 1977-11-29 | 1980-12-30 | Aga Aktiebolag | Arrangement in respirators using a fluidistor to determine volume of air passed to a patient and pressure sensor to correct volume reading in terms of actual pressure |
US4281651A (en) * | 1977-05-06 | 1981-08-04 | Airco, Inc. | Lung ventilator |
US4380233A (en) * | 1980-01-04 | 1983-04-19 | Synthelabo | Control device for an artificial respirator |
US4612928A (en) * | 1984-08-28 | 1986-09-23 | Tiep Brian L | Method and apparatus for supplying a gas to a body |
US4702240A (en) * | 1986-07-22 | 1987-10-27 | Bear Medical Systems, Inc. | Demand-responsive gas blending system for medical ventilator |
US4874362A (en) * | 1986-03-27 | 1989-10-17 | Wiest Peter P | Method and device for insufflating gas |
US4957107A (en) * | 1988-05-10 | 1990-09-18 | Sipin Anatole J | Gas delivery means |
US5048515A (en) * | 1988-11-15 | 1991-09-17 | Sanso David W | Respiratory gas supply apparatus and method |
US6371113B1 (en) * | 1996-10-10 | 2002-04-16 | Datex-Ohmeda, Inc. | Zero flow pause during volume ventilation |
US20050039749A1 (en) * | 2003-09-08 | 2005-02-24 | Emerson George P. | Insufflation-exsufflation system for removal of broncho-pulmonary secretions with automatic triggering of inhalation phase |
US20050051174A1 (en) * | 2003-09-08 | 2005-03-10 | Emerson George P. | Insufflation-exsufflation system with percussive assist for removal of broncho-pulmonary secretions |
US20060260612A1 (en) * | 2005-05-20 | 2006-11-23 | Drager Safety Ag & Co. Kgaa | Compressed air respirator |
US20090065007A1 (en) * | 2007-09-06 | 2009-03-12 | Wilkinson William R | Oxygen concentrator apparatus and method |
US20100252046A1 (en) * | 2007-07-06 | 2010-10-07 | Dahlstroem Bo | Expiratory valve of an anesthetic breathing apparatus having safety backup |
US20110253136A1 (en) * | 2008-06-05 | 2011-10-20 | Resmed Limited | Treatment of respiratory conditions |
US8603228B2 (en) | 2010-09-07 | 2013-12-10 | Inova Labs, Inc. | Power management systems and methods for use in an oxygen concentrator |
US8616207B2 (en) | 2010-09-07 | 2013-12-31 | Inova Labs, Inc. | Oxygen concentrator heat management system and method |
US8844526B2 (en) | 2012-03-30 | 2014-09-30 | Covidien Lp | Methods and systems for triggering with unknown base flow |
US9364624B2 (en) | 2011-12-07 | 2016-06-14 | Covidien Lp | Methods and systems for adaptive base flow |
US9440179B2 (en) | 2014-02-14 | 2016-09-13 | InovaLabs, LLC | Oxygen concentrator pump systems and methods |
US9440180B2 (en) | 2012-10-12 | 2016-09-13 | Inova Labs, Llc | Oxygen concentrator systems and methods |
US9440036B2 (en) | 2012-10-12 | 2016-09-13 | InovaLabs, LLC | Method and systems for the delivery of oxygen enriched gas |
US9498589B2 (en) | 2011-12-31 | 2016-11-22 | Covidien Lp | Methods and systems for adaptive base flow and leak compensation |
US9649458B2 (en) | 2008-09-30 | 2017-05-16 | Covidien Lp | Breathing assistance system with multiple pressure sensors |
US9717876B2 (en) | 2012-10-12 | 2017-08-01 | Inova Labs, Inc. | Dual oxygen concentrator systems and methods |
US9808591B2 (en) | 2014-08-15 | 2017-11-07 | Covidien Lp | Methods and systems for breath delivery synchronization |
US9925346B2 (en) | 2015-01-20 | 2018-03-27 | Covidien Lp | Systems and methods for ventilation with unknown exhalation flow |
US9950129B2 (en) | 2014-10-27 | 2018-04-24 | Covidien Lp | Ventilation triggering using change-point detection |
US9981096B2 (en) | 2013-03-13 | 2018-05-29 | Covidien Lp | Methods and systems for triggering with unknown inspiratory flow |
US11324954B2 (en) | 2019-06-28 | 2022-05-10 | Covidien Lp | Achieving smooth breathing by modified bilateral phrenic nerve pacing |
US11458274B2 (en) | 2016-05-03 | 2022-10-04 | Inova Labs, Inc. | Method and systems for the delivery of oxygen enriched gas |
Families Citing this family (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPS54167698U (en) * | 1978-05-16 | 1979-11-26 | ||
SE434799B (en) * | 1980-06-18 | 1984-08-20 | Gambro Engstrom Ab | SET AND DEVICE FOR CONTROL OF A LUNG FAN |
GB2433445A (en) * | 2005-08-16 | 2007-06-27 | Vladimir Davidov | Respiratory monitor for a rebreather |
-
1970
- 1970-01-21 GB GB293870A patent/GB1338226A/en not_active Expired
-
1971
- 1971-01-18 US US00106960A patent/US3768468A/en not_active Expired - Lifetime
- 1971-01-19 DK DK20771AA patent/DK134634B/en unknown
- 1971-01-20 FR FR7101844A patent/FR2075764A5/fr not_active Expired
- 1971-01-21 DE DE19712102837 patent/DE2102837A1/en not_active Withdrawn
- 1971-01-21 SE SE7100721A patent/SE370495B/xx unknown
- 1971-01-21 NL NL7100834A patent/NL7100834A/xx unknown
- 1971-01-21 JP JP46001777A patent/JPS5223198B1/ja active Pending
Cited By (66)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3923056A (en) * | 1974-06-19 | 1975-12-02 | Gen Electric | Compliance compensation for electronically controlled volume respirator systems |
US3946729A (en) * | 1974-10-17 | 1976-03-30 | Hewlett-Packard Company | Ventilator patient monitor |
US3976065A (en) * | 1975-03-10 | 1976-08-24 | Gerald Durkan | Digital fluidic ventilator |
US4206754A (en) * | 1976-06-02 | 1980-06-10 | Boc Limited | Lung ventilators |
US4281651A (en) * | 1977-05-06 | 1981-08-04 | Airco, Inc. | Lung ventilator |
US4241732A (en) * | 1977-11-29 | 1980-12-30 | Aga Aktiebolag | Arrangement in respirators using a fluidistor to determine volume of air passed to a patient and pressure sensor to correct volume reading in terms of actual pressure |
US4380233A (en) * | 1980-01-04 | 1983-04-19 | Synthelabo | Control device for an artificial respirator |
US4612928A (en) * | 1984-08-28 | 1986-09-23 | Tiep Brian L | Method and apparatus for supplying a gas to a body |
US4874362A (en) * | 1986-03-27 | 1989-10-17 | Wiest Peter P | Method and device for insufflating gas |
US4702240A (en) * | 1986-07-22 | 1987-10-27 | Bear Medical Systems, Inc. | Demand-responsive gas blending system for medical ventilator |
US4957107A (en) * | 1988-05-10 | 1990-09-18 | Sipin Anatole J | Gas delivery means |
US5048515A (en) * | 1988-11-15 | 1991-09-17 | Sanso David W | Respiratory gas supply apparatus and method |
US6371113B1 (en) * | 1996-10-10 | 2002-04-16 | Datex-Ohmeda, Inc. | Zero flow pause during volume ventilation |
US20050039749A1 (en) * | 2003-09-08 | 2005-02-24 | Emerson George P. | Insufflation-exsufflation system for removal of broncho-pulmonary secretions with automatic triggering of inhalation phase |
US6860265B1 (en) * | 2003-09-08 | 2005-03-01 | J.H. Emerson Company | Insufflation-exsufflation system for removal of broncho-pulmonary secretions with automatic triggering of inhalation phase |
US20050051174A1 (en) * | 2003-09-08 | 2005-03-10 | Emerson George P. | Insufflation-exsufflation system with percussive assist for removal of broncho-pulmonary secretions |
US6929007B2 (en) | 2003-09-08 | 2005-08-16 | J.H. Emerson Company | Insufflation-exsufflation system with percussive assist for removal of broncho-pulmonary secretions |
US20060260612A1 (en) * | 2005-05-20 | 2006-11-23 | Drager Safety Ag & Co. Kgaa | Compressed air respirator |
US7578293B2 (en) * | 2005-05-20 | 2009-08-25 | Dräger Safety AG & Co. KGaA | Compressed air respirator |
US8967145B2 (en) * | 2007-07-06 | 2015-03-03 | Maquet Critical Care Ab | Expiratory valve of an anesthetic breathing apparatus having safety backup |
US20100252046A1 (en) * | 2007-07-06 | 2010-10-07 | Dahlstroem Bo | Expiratory valve of an anesthetic breathing apparatus having safety backup |
US8915248B2 (en) | 2007-09-06 | 2014-12-23 | Inova Labs, Inc. | Oxygen concentrator apparatus and method with an oxygen assisted venting system |
US20090065007A1 (en) * | 2007-09-06 | 2009-03-12 | Wilkinson William R | Oxygen concentrator apparatus and method |
US20110030689A1 (en) * | 2007-09-06 | 2011-02-10 | Inova Labs, Inc. | Oxygen concentrator apparatus and method having an ultrasonic detector |
US20110030686A1 (en) * | 2007-09-06 | 2011-02-10 | Inova Labs, Inc. | Oxygen concentrator apparatus and method having variable operation modes |
US20110030684A1 (en) * | 2007-09-06 | 2011-02-10 | Inova Labs, Inc. | Oxygen concentrator apparatus and method having flow restricted coupling of the canisters |
US9649465B2 (en) | 2007-09-06 | 2017-05-16 | Inova Labs, Inc. | Oxygen concentrator apparatus and method having variable operation modes |
US9649464B2 (en) | 2007-09-06 | 2017-05-16 | Inova Labs, Inc. | Oxygen concentrator apparatus and method having an ultrasonic detector |
US9956370B2 (en) | 2007-09-06 | 2018-05-01 | Inova, Labs, LLC. | Oxygen concentrator apparatus and method having flow restricted coupling of the canisters |
US8794237B2 (en) | 2007-09-06 | 2014-08-05 | Inova Labs, Inc. | Oxygen concentrator apparatus and method having flow restricted coupling of the canisters |
US20110030687A1 (en) * | 2007-09-06 | 2011-02-10 | Inova Labs, Inc. | Oxygen concentrator apparatus and method with an oxygen assisted venting system |
US20110030685A1 (en) * | 2007-09-06 | 2011-02-10 | Wilkinson William R | Oxygen concentrator apparatus and method of delivering pulses of oxygen |
US10806889B2 (en) | 2008-06-05 | 2020-10-20 | ResMed Pty Ltd | Treatment of respiratory conditions |
US11878123B2 (en) | 2008-06-05 | 2024-01-23 | ResMed Pty Ltd | Treatment of respiratory conditions |
US11433213B2 (en) | 2008-06-05 | 2022-09-06 | ResMed Pty Ltd | Treatment of respiratory conditions |
US11247019B2 (en) | 2008-06-05 | 2022-02-15 | ResMed Pty Ltd | Treatment of respiratory conditions |
US11229766B2 (en) | 2008-06-05 | 2022-01-25 | ResMed Pty Ltd | Treatment of respiratory conditions |
US20110253136A1 (en) * | 2008-06-05 | 2011-10-20 | Resmed Limited | Treatment of respiratory conditions |
US10675432B2 (en) | 2008-06-05 | 2020-06-09 | ResMed Pty Ltd | Treatment of respiratory conditions |
US10350379B2 (en) * | 2008-06-05 | 2019-07-16 | ResMed Pty Ltd | Treatment of respiratory conditions |
US9649458B2 (en) | 2008-09-30 | 2017-05-16 | Covidien Lp | Breathing assistance system with multiple pressure sensors |
US8616207B2 (en) | 2010-09-07 | 2013-12-31 | Inova Labs, Inc. | Oxygen concentrator heat management system and method |
US8603228B2 (en) | 2010-09-07 | 2013-12-10 | Inova Labs, Inc. | Power management systems and methods for use in an oxygen concentrator |
US9364624B2 (en) | 2011-12-07 | 2016-06-14 | Covidien Lp | Methods and systems for adaptive base flow |
US11497869B2 (en) | 2011-12-07 | 2022-11-15 | Covidien Lp | Methods and systems for adaptive base flow |
US10543327B2 (en) | 2011-12-07 | 2020-01-28 | Covidien Lp | Methods and systems for adaptive base flow |
US10709854B2 (en) | 2011-12-31 | 2020-07-14 | Covidien Lp | Methods and systems for adaptive base flow and leak compensation |
US11833297B2 (en) | 2011-12-31 | 2023-12-05 | Covidien Lp | Methods and systems for adaptive base flow and leak compensation |
US9498589B2 (en) | 2011-12-31 | 2016-11-22 | Covidien Lp | Methods and systems for adaptive base flow and leak compensation |
US8844526B2 (en) | 2012-03-30 | 2014-09-30 | Covidien Lp | Methods and systems for triggering with unknown base flow |
US10029057B2 (en) | 2012-03-30 | 2018-07-24 | Covidien Lp | Methods and systems for triggering with unknown base flow |
US9717876B2 (en) | 2012-10-12 | 2017-08-01 | Inova Labs, Inc. | Dual oxygen concentrator systems and methods |
US11364359B2 (en) | 2012-10-12 | 2022-06-21 | Inova Labs, Inc. | Method and systems for the delivery of oxygen enriched gas |
US11684744B2 (en) | 2012-10-12 | 2023-06-27 | Inova Labs, Inc. | Method and systems for the delivery of oxygen enriched gas |
US9440036B2 (en) | 2012-10-12 | 2016-09-13 | InovaLabs, LLC | Method and systems for the delivery of oxygen enriched gas |
US9440180B2 (en) | 2012-10-12 | 2016-09-13 | Inova Labs, Llc | Oxygen concentrator systems and methods |
US9981096B2 (en) | 2013-03-13 | 2018-05-29 | Covidien Lp | Methods and systems for triggering with unknown inspiratory flow |
US9440179B2 (en) | 2014-02-14 | 2016-09-13 | InovaLabs, LLC | Oxygen concentrator pump systems and methods |
US10864336B2 (en) | 2014-08-15 | 2020-12-15 | Covidien Lp | Methods and systems for breath delivery synchronization |
US9808591B2 (en) | 2014-08-15 | 2017-11-07 | Covidien Lp | Methods and systems for breath delivery synchronization |
US9950129B2 (en) | 2014-10-27 | 2018-04-24 | Covidien Lp | Ventilation triggering using change-point detection |
US10940281B2 (en) | 2014-10-27 | 2021-03-09 | Covidien Lp | Ventilation triggering |
US11712174B2 (en) | 2014-10-27 | 2023-08-01 | Covidien Lp | Ventilation triggering |
US9925346B2 (en) | 2015-01-20 | 2018-03-27 | Covidien Lp | Systems and methods for ventilation with unknown exhalation flow |
US11458274B2 (en) | 2016-05-03 | 2022-10-04 | Inova Labs, Inc. | Method and systems for the delivery of oxygen enriched gas |
US11324954B2 (en) | 2019-06-28 | 2022-05-10 | Covidien Lp | Achieving smooth breathing by modified bilateral phrenic nerve pacing |
Also Published As
Publication number | Publication date |
---|---|
DE2102837A1 (en) | 1971-07-29 |
JPS5223198B1 (en) | 1977-06-22 |
SE370495B (en) | 1974-10-21 |
DK134634C (en) | 1977-05-16 |
FR2075764A5 (en) | 1971-10-08 |
DK134634B (en) | 1976-12-13 |
NL7100834A (en) | 1971-07-23 |
GB1338226A (en) | 1973-11-21 |
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