JP3179471B2 - Ventilator control device - Google Patents

Description

Description: FIELD OF THE INVENTION The present invention relates generally to respiratory ventilators, and more particularly, to pneumatic actuation of mixing gases and delivering respiratory gases for controlled or spontaneous breathing. The present invention relates to an electronically controlled ventilator device.

2. Description of the Related Art Conventional respiratory ventilators generally deliver a positive over-pressure breathing gas to a patient and deliver the pressurized breathing gas in a predetermined manner in response to pressure fluctuations in the patient's breathing pattern. Alternatively, it can be activated to deliver a predetermined volume of breathing gas to the patient, controlled for each breath. Respiratory gases generally contain high concentrations of oxygen. A reservoir for receiving oxygen-enriched gas, a sensor for monitoring the gas being withdrawn from the reservoir, and a gas having a predetermined oxygen concentration at the detected withdrawal rate. An oxygen concentrator comprising a microprocessor for determining a minimum time to fill a gas is disclosed in US Pat.
This is described in 61,287. Multiple canisters with molecular sieve beds to absorb nitrogen are equipped with a valve mechanism to send oxygen-enriched gas to a reservoir and direct air from the compressor to another sieve bed . Another device for mixing two gases in a predetermined ratio comprises means for introducing two gases entering the pressure vessel via separate inlets, the means for introducing the gas mixture in an appropriate ratio. To form, accept a first gas until a first pressure and then accept a second gas until a second pressure. This device is described in U.S. Pat. Nos. 4,022,234 and 4,023,587 to Dobritz. The gas mixture is withdrawn in the receiving vessel until an initial pressure is reached, at which time the gas withdrawal is interrupted and the mixing cycle starts again. Feedback control of the flow and pressure of breathing gas to the patient by an inhalation servo unit is also described in Johnson et al., US Pat.
It is described in 1,208.

The constituent gases of the respiratory gas in a predetermined manner in response to the pressure of the respiratory gas contained in the receiving container and according to the various aspects of the respiration that the respiratory gas is provided It would be desirable to provide a ventilator device that can mix

SUMMARY OF THE INVENTION The present invention provides an apparatus for delivering respiratory gas from an enclosure to a patient, the apparatus including a method for measuring the amount of gas in the enclosure and controlling the pressure in the enclosure. This includes controlling the flow of breathing gas into the enclosure in response and controlling the outflow of breathing gas in response to fluctuations in the pressure or volume of the enclosure.

Briefly and generally, a ventilator device for delivering breathing gas to a patient comprises an enclosure, inlet means connecting the enclosure to a source of breathing gas, and an outlet connecting the enclosure to the patient. Means, a sensor for detecting the amount of gas in the enclosure, means for controlling the flow of breathing gas into the enclosure in response to the amount of gas detected in the enclosure, and the enclosure Means for controlling the outflow of respiratory gas in response to variations in the amount of gas therein.

In a preferred embodiment of the device of the present invention, means for determining the outflow rate of gas from the container based on the pressure or volume detected in the container, and for comparing the outflow speed with a predetermined value. Means and means for adjusting the spill based on this comparison are also provided. The inlet flow control also preferably includes a device for comparing the pressure or volume in the container to a predetermined value, and a valve mechanism for filling the container in response to the comparison. In another preferred embodiment of the present invention, based on the expected rate of change in the vessel,
Means for determining the expected pressure or volume of the enclosure are provided with a valve mechanism for filling the container in response to the expected pressure or volume. The enclosure preferably also contains means for reducing temperature fluctuations of the respiratory gas contained in the container.

The ventilator of the present invention supports two basic modes of breathing. Forced breathing is supported, in which case,
The physical characteristics of the breath delivered to the patient are completely specified by the operator's selected settings. The physical properties selected by the operator may include waveforms, tidal volume, peak inspiratory flow, composition such as oxygen concentration and cycle time. The mandatory breathing pattern can also be initiated by an independent operator or patient.

Spontaneous breathing patterns are also supported by the present invention.
In spontaneous breathing, the flow of inhaled gas and the volume of a single dose are determined only by the actions of the patient. However, the composition of the breathing gas is determined by the value of certain parameters of the oxygen concentration. Respiratory gas flow to the patient can be controlled by the operator's selected set point positive end inhalation pressure (PEEP) and sensitivity, triggered by variations in air passage pressure. A continuous positive air passage pressure (CPAP) is provided. "Sensitivity" is the pressure level below PEEP and must be created by the patient to cause a patient-initiated mandatory breath or spontaneous breath from the ventilator. The mandatory breath can be initiated by the ventilator, operator or patient according to the parameter settings. The ventilator-initiated breath is delivered at regular cycle intervals determined by the operator-selected value for respiratory rate.
The operator initiated breathing is determined by manual control by the operator. The patient-initiated breath is delivered whenever the patient reduces the airway pressure below PEEP by an amount equal to the value selected by the operator for sensitivity.

The present invention also provides for precise control of the oxygen concentration in the breathing gas. Gas measurements are based on the ideal gas law, which states that the product of the pressure and volume of a gas is proportional to the product of the number of moles of the gas and its temperature. That is, PV = NRT where P is the absolute pressure of the gas, V is the volume of the gas, N is the number of moles of the gas, R is the gas constant, and T is the temperature of the gas.

Thus, the number of moles of gas in a fixed volume vessel can be determined indirectly by measuring volume, gas pressure and gas temperature. With a simple extension of this law, if gas is added to or removed from the container,
The pressure will fluctuate by the following proportional amount:

ΔP = ΔNRT / V (1) In addition, two ideal gases occupying the same space behave according to Dalton's law of partial pressure. That is, P = (N1 + N2) RT / V (2) The mixing control algorithm is based on equations (1) and (2). From equation (1), the number of moles of gas injected into the container is proportional to the measured pressure fluctuation. That is, ΔN = ΔPV / TR (3) Thus, with proper scaling of the container, the pressure fluctuation measurement can be read directly as the number of moles of the fixed volume container for the injected gas, which is referred to as the gas mixture. Can be used for control.

From equation (2), the number of moles of each gas in the respiratory gas-filled container is
That is, the respective molar numbers NO, NA of the first gas (eg, oxygen) and the second gas (eg, air).
Can be calculated from the molar ratio and pressure of the enclosure. That is, NA = mixing ratio · PV / TR (4) NO = (1-mixing ratio) · PV / TR (5) In order to fill the enclosure with a desired mixture ratio, the moles of the first gas in the enclosure are The number or number of molecules is evaluated by applying equations (4) and (5). The desired number of moles or molecules for each gas can be calculated by applying these equations for the desired mixing ratio and pressure, and the differential pressure for each gas is calculated using equation (3). Can be converted to pressure. By injecting each gas in order until these pressure values are reached, an accurate gas amount can be guided to the enclosure. The same calculation of the mixing ratio and volume of the gas in the container should be performed for a container whose volume can be varied, whether the pressure is kept constant or the pressure is also fluctuated. Can be.

This approach offers several significant advantages over other batch-type mixing devices. Since the solenoids can be operated separately to increase, for example, the oxygen concentration, rapid mixing fluctuations are possible and the oxygen solenoid must be used exclusively in several cycles until the desired mixing ratio is reached. Can be. In addition, pressure transducers and volume detectors provide very accurate and reliable gas pressure measurements, and continuous readjustment to correct for any fluctuations caused by mechanical valves. As a result, highly accurate mixing is possible. For example, if the fill solenoid valve happens to remain open for a short time after being signaled to close, the resulting increase in pressure will be even higher with the additional amount of gas allowed. Will reflect. As the mixing ratio is determined from the variation in measured pressure or volume, this variation will be adjusted and therefore the amount of gas allowed in the next fill will be less.

Other features and advantages of the invention will be apparent from the following detailed description, which illustrates, by way of example, the features of the invention, and the accompanying drawings.

EXAMPLE As shown in the illustration, the present invention is embodied in a ventilator controller having separate inlet passages for each pressurized gas, the inlet passages being air operated solenoids for each gas. Connected to valve. The outlet of each gas solenoid valve that creates a gas mixture is connected to an enclosure or tank, and the gases mix in the tank when each solenoid valve is activated. An enclosure is a gas receiving tank or container that is filled by a flow of gas from one or more inlet conduits. The pressure is monitored by a precision pressure transducer connected to the tank, and the outlet port of the enclosure is connected to an electrically actuated flow control valve by a gas flow path. In the present invention, the gas pressure or volume in the container is measured, and from this information and the ratio of oxygen to the other gas initially in the tank, an initial gas ratio is determined. The tank fill target pressure or volume is determined from the user-defined oxygen concentration parameters and the initial tank gas ratio, and each gas solenoid is then activated to fill the tank from an initial value to a target value. While filling the tank, the outlet flow control valve is closed, but once the gas proportional filling cycle is completed, the outlet flow control is activated,
A precisely proportioned flow of the oxygen gas mixture is provided to the patient in response to need. When the gas flow out of the tank reduces the gas volume to a predetermined minimum, the proportional refill cycle is repeated.

In accordance with the present invention, there is provided a ventilator device for intermittently delivering breathing gas to a patient, the device comprising a pressure-enclosed container having a rigid, fixed wall, and first and second inlets connected to the container. Ports, each of the ports being in fluid communication with a separate first and second source of first and second respective component gases that are mixed in a desired ratio to form a breathing gas. The first and second inlet ports have an initial known ratio, and the first and second inlet ports have associated first and second inlet valves that can independently control the flow of component gases through the inlet ports to the vessel. And the ventilator device further comprises an outlet means for connecting the container to the patient in fluid communication, and determines the start and completion of inhalation of the patient,
Pressure transducer means for detecting the pressure of breathing gas in the enclosure following completion of inhalation of the patient and generating a differential pressure signal indicative of a rate of pressure change in the enclosure over a period of time; and a second inlet port. While the first inlet port is closed, the flow of the first component gas is sequentially controlled into the sealed container through the first inlet port in response to the completion of inhalation completion of the patient. , A flow control means for the inlet valve for controlling the flow of the second component gas through the second inlet port and at a desired rate responsive to the gas pressure detected in the sealed container, comprising: The desired pressure change of each component gas in the sealed container corresponding to each mole of the component gas required to fill the component gas with a desired ratio to a predetermined filling pressure is determined by the total pressure in the container and the component gas. Decision based on initial publicly known ratio Means for controlling the flow rate of the component gas in the respiratory gas in the container, and means for determining based on the detected pressure change of the component gas introduced into the sealed container, and a pressure transducer. Controlling the flow of breathing gas through the outlet means in a predetermined manner in response to a differential pressure signal based on the rate of change of the gas pressure detected in the sealed container, following the initiation of inhalation, following the inhalation initiation. Outlet flow control means.

Referring to FIG. 1, a ventilator air control system 10 is shown.
Comprises a receiving tank 12, which in one of the widely practiced preferred embodiments is a rigid, fixed-wall, pressure-filled container, typically having a volume of about 2 liters. Copper wool material 14 completely fills the interior volume of the tank, typically reaching 2% of the tank volume. Copper wool with a high specific heating value allows the pressurization and depressurization of the gas to be relatively isothermal during the fill and draw cycles. Other similar materials may be used to reduce temperature fluctuations of the gas contained within the container. The enclosure may alternatively consist of a piston chamber or bellows-type chamber and may be adapted to form various volumes while maintaining a substantially constant pressure, or both the volume and the pressure may be varied, Both may be monitored.

The receiving tank preferably has an oxygen inlet port 16 connected to an oxygen supply 17. Similarly, the receiving tank preferably also has an air inlet port connected to an air supply 19. The oxygen and air supply may simply be a high pressure tank of oxygen and air, and the air supply may also be an air compressor. It could be other conventional sources of pressurized oxygen and air provided in hospitals. Alternatively, the air inlet tube and the oxygen inlet tube may be joined and the gases premixed before entering the enclosure.

Oxygen supply conduit 20 may carry oxygen from the oxygen inlet port to the tank, and air supply conduit 22 may carry air to the receiving tank. The oxygen inlet tube also has a solenoid valve 24, normally in a closed position, which can be actuated by an electronic control to supply pressurized oxygen to a receiving tank. Similarly, the air supply line is provided with a solenoid valve operated by an electronic control unit to deliver pressurized air to a receiving tank.

An outlet conduit 28 for supplying breathing gas from the receiving tank to the patient and a pressure transducer for sensing pressure.
30 is connected to the receiving tank. The electronic control means 32, which preferably comprises a microprocessor for controlling all of the functions of the ventilator controller, comprises an oxygen solenoid valve, an air solenoid valve, a container pressure sensor, and an adjustable inlet servo valve at the outlet conduit. It is connected to outlet solenoid valve control means 34 which serves to control 35.

Referring to FIG. 2, the elements numbered 110 through 134 correspond to the elements numbered 10 through 34, respectively. In a preferred embodiment of the invention, the oxygen inlet conduit also
An oxygen gas filter 136 is provided, and the air inlet conduit is provided with a compressed air filter 138. Check valve 1
40 and 142 are also provided in the oxygen and air inlet conduit, and oxygen pressure switch 144 and air pressure switch 146
Connected near the gas inlet port to monitor the low pressure gas supply. A cross solenoid 148 is also preferably connected in series between the oxygen inlet conduit and the air inlet conduit to provide a ventilator with another source of oxygen pressure in the event of a failure of the normal respiratory gas system. A pressure switch 150 is connected to the receiving tank near the tank pressure sensor and is used to electrically check the effectiveness of the pressure transducer. A release valve 152 is also connected to the receiving tank and is used to release overpressure conditions caused by equipment or component failure.

Gas flow through the ventilator is monitored by a second pressure sensor, and an absolute pressure transducer 154 is connected to the breathing gas outlet conduit to the patient. The measurements made by the outlet flow absolute pressure transducer are used to determine patient device occlusion and atmospheric pressure, and to monitor the effectiveness of the patient breathing circuit pressure reading. A safety release valve 156 is also provided on the respiratory gas flow tube and serves to vent excess pressure of the respiratory gas outlet stream to vent 157. Safety valve solenoid 158 and control element 1
60a and 160b are also connected in series with a safety regulator connected in communication with the cross solenoid and provide the basis for a safety device to deliver air to the patient if the normal ventilator air system fails. Form. Thus, the safety release valve serves the dual purpose of venting overpressure and, if necessary, sending air to the respiratory gas outlet stream to the patient. The safety device also includes an outlet pipe check valve 164.

A ventilator nebulizer pressure source is provided by nebulizer solenoid 166 and receives a pressure supply from nebulizer 168 which is directly connected to the receiving tank. Actuation of the nebulizer will not change the controlled volume supply or oxygen ratio of the breathing gas.

The output gas flow of the ventilator is also
Filtered by zero and delivered to the patient by a patient tube (not shown). The exhaled gas is
The tube (not shown) connected to the water trap 171 at the exhalation valve inlet 172 of the patient breathing circuit returns to the ventilator. Another ventilator component is connected by a patient pressure port at the exhalation valve inlet. These are a third pressure sensor 173, a pressure gauge 174 used to monitor patient device pressure, and an automatic zeroing solenoid 176 used to electrically zero the patient breathing circuit pressure sensor 173. .

An exhalation servo valve 180 is used to control the exhalation gas flow of the patient flowing into the room. The exhalation servo valve is a direct drive servo valve driven by an electric motor and controlled by ventilator electronics.
The motor is mechanically connected to the exhalation valve 182 of the breathing circuit. The spirometer 184 is a two-part device consisting of an overall flow sensor 186 and a flow venturi 188. The spirometry monitored by the global flow sensor and the flow venturi provides gas flow measurements to the ventilator electronics for both patient data display and ventilator status warning components. This electronic device controls all of the functions and inputs of the ventilator air system and includes not only the nebulizer solenoid and the automatic zero-setting solenoid of the patient device pressure circuit, but also the oxygen inlet, air inlet and cross solenoid, the inhalation servo valve and the safety solenoid. Control. Each of the three pressure and flow sensors is also connected to the electronics and provides data relating to the operation of the ventilator device.

Oxygen and Air Distribution In normal ventilator operation, when power is first turned on, the vessel pressure is at atmospheric pressure. After completing the power up operation, the breathing algorithm begins execution.

First, the vessel pressure is measured and the conventional oxygen concentration is retrieved from memory. The number of molecules (NA, NO) of each gas type is evaluated by applying the equations (4) and (5). The mixing and volume commands from the keyboard are then used to calculate the total pressure of the container and the desired number of molecules (NAD, NOD) for each gas type. Subtract the evaluated value from the desired value to obtain the number of each type of molecule to be injected. Finally, these values are converted into equivalent pressure fluctuation values (ΔPA, ΔPO) by applying the equation (2).

After calculating the pressure fluctuation value for each gas, the target pressure level is calculated. Open the first solenoid valve to fill the container and then close the valve when the pressure reaches the first target pressure. After a brief pause, the pressure in the container is measured and stored. Next, the second solenoid valve is opened and then closed when the second target pressure level is reached. After a brief pause, the vessel pressure is measured and stored again.

Mixing was based on accurate solenoid actuation,
The true mixture value is now more accurately evaluated using equations (4), (5) and the intermediate pressure measurement. This evaluation replaces the previous mixture value stored in memory.

Subsequent inhalation takes place and gas from the container is delivered to the patient through the servo valve until the desired volume is delivered (forced breath) or until the patient triggers the end of breath (spontaneous breathing). . In both cases, the mixing algorithm is performed again.

Here, the algorithm depends on the clinician's choice.
Follow two different procedures. In the spontaneous mode, the current vessel pressure is compared to a threshold value. Only when it falls below this limit does a new mixing cycle start and the container is completely filled. If it is, no mixing will take place. The method using this limit is
Used to reduce mixing inaccuracies due to pressure measurement errors.

In the forced mode, the vessel pressure for the next cycle is
Evaluated based on current pressure and volume delivered to patient in next cycle. In particular, the pressure fluctuations expected from a single volume feed are subtracted from the current pressure. This evaluation value is then compared to the limit value, and if it is below, a new mixing cycle is performed as described above. Otherwise, the mixing step is skipped. In this way, the vessel pressure can always be maintained above the limit required for sprayer operation.

Example 1. Air / Oxygen Mixing Control This example shows the case where a complete mixing cycle is configured. FIG. 3 shows the container pressure versus time during the mixing operation. Notable events include: 1. Sending gas to the patient through a servo valve (200).

2. Complete the gas supply and close the servo motor (20
2).

 Store the container pressure.

 Retrieve previous mixed value from memory.

 Evaluate the current amount of each gas.

Retrieve the mixed instruction input from the keyboard from the memory.

 Calculate the desired vessel pressure as follows.

 a. Mandatory mode: adding a limit value to the supply pressure.

 b. Spontaneous mode: Use re-large vessel pressure

 Calculate the desired amount of each gas.

 Subtraction gives the amount of each gas to be injected.

3. Open the oxygen solenoid valve (204).

 Monitor pressure as oxygen is added.

4. The pressure reaches the oxygen target (206).

 Close the oxygen solenoid.

5. Calm the pressure with a short pause (208).

6. Measure the pressure (210).

 Calculate and store pressure fluctuations due to oxygen.

7. Open the air solenoid valve (212).

 Monitor pressure as air is added.

8. Pressure reaches air target (214).

 Close the air solenoid.

9. Calm the pressure with a short pause (216).

10. Measure the pressure (218).

 Calculate and store pressure fluctuations due to air.

New mixing values are evaluated from the measured air and oxygen pressure fluctuations.

11. Begin breathing and gas begins to flow to the patient (220).

Example 2. Refill logic for spontaneous breathing Since spontaneous breathing is controlled by the patient, its capacity cannot be predicted. The container must be completely refilled after a significant amount of breathing, to be able to meet the demand for large respiratory volume on the next inhalation. In addition to this, the accuracy of the mixing is largely dependent on a considerable amount of refill pressure fluctuations, so that threshold values are used to minimize pressure fluctuations. A typical pressure history is shown in FIG.

1. The patient inhales (222).

2. The patient ends the inhalation (224).

 The container pressure is stored and compared with the limit value.

 Since the pressure is below the limit value, refilling is performed.

 Set target to 30 psi.

3. Mixing control is performed as in Example 1 (226).

4. Pressure reaches 30 psi (228).

 The mixing control ends.

 Wait for the patient to inhale.

5. The patient inhales (230).

6. The patient ends the inhalation (232).

 The vessel pressure is stored and compared with a limit value.

 Refilling is not performed because the pressure is above the limit.

 Wait for the patient to inhale.

7. The patient inhales (234).

8. The patient ends the inhalation (236).

 The vessel pressure is stored and compared with a limit value.

 Since the pressure is below the limit value, refilling is performed.

 Set target to 30 psi.

9. Perform mixing control as in Example 1 (238).

Example 3. Refill logic for large mandatory breaths Because mandatory breaths form a predetermined volume, it is not necessary to completely refill the container after each inhalation. This allows operation at lower pressures, where the servo valves are more linear and provide improved flow control. However, sufficient atomizer pressure must be ensured using the minimum pressure limit. The vessel pressure is always maintained above the limit. A typical pressure history in this case is shown in FIG.

1. Send gas to the patient (240).

2. When the desired volume is reached, the inhalation ends (242).

 Store the container pressure.

 Predict the pressure after the next breath.

 Since the expected pressure is below the limit value, refilling is performed.

3. Mixing control is performed as in Example 1 (244).

Because of the large volume in this example, the pressure will always be below the threshold, so refilling will take place after each breath.

Example 4. Refill logic for small mandatory breaths Small mandatory breaths do not necessarily result in small fluctuations in vessel pressure, and do not necessarily need to be refilled after each absorption. This prevents mixing inaccuracies and solenoid valve wear. FIG. 6 shows a good example.

1. Send gas to the patient (246).

2. Inhalation ends when the desired volume is reached (248).

 Store the container pressure.

 Predict the pressure after the next breath.

Since the expected value is above the limit value, no refilling is performed.

3. Send gas to the patient (250).

4. The inhalation ends when the desired volume is reached (252).

 Store the container pressure.

 Predict the pressure after the next breath.

Since the expected value is below the limit value, refilling is performed.

5. Mixing control is performed as in Example 1 (254).

6. Complete mixing control (256).

 Wait for the patient to breathe.

Controlled Volume Delivery In limited volume forced breaths, the operator determines the parameters of a single volume and the required peak flow, inputs these parameters to the electronic controller, and the ventilator device Respiratory volume can be provided. The ventilator drive gas pressure is stored in a receiving tank. During the inhalation phase, the oxygen inlet solenoid valve and the air inlet solenoid valve remain closed, and the receiving tank pressure sensor usually monitors the pressure and volume level in the receiving tank. At the start of inhalation, the initial pressure in the receiving tank is received from the pressure sensor and entered into the microprocessor memory, and the breathing gas outlet solenoid servo valve is activated to regulate the flow to the patient.

For peak flow control, the electronic differential pressure signal from the receiving tank pressure transducer is used to determine the gas flow exiting the receiving tank. This dp / dt signal is used by the electronic controller to send a control loop to the suction servo valve to maintain the desired set flow rate. An absolute pressure transducer in the outlet conduit located downstream of the inhalation servo valve measures atmospheric pressure and detects an occlusion in the breathing circuit.

The rectangular waveform of the ventilator flow is the standard way to deliver a controlled volume. Volume control is performed by directly measuring the start and end pressures of the receiving tank during the inhalation phase of breathing. The capacity is determined indirectly from pressure fluctuations in the receiving tank according to the ideal gas flow equation.

The spontaneous breathing aspect of the ventilator is an important function of the ventilator of the present invention. The responsiveness of the ventilator to the breathing required by the patient determines the respiratory characteristics. To best meet the needs of the patient, by placing the servo control loop of the patient pressure sensor 173 in the exhalation flow path of the patient's tubing, the ventilator controller will provide a spontaneous breathing mode in which the proportional servo valve is controlled.

The foregoing description shows that the apparatus of the present invention allows for the controlled flow of respiratory gas into the pressure enclosure in a predetermined manner, depending on the pressure within the enclosure and the manner in which the respiratory gas is supplied to the patient. Was. Also, the apparatus of the present invention may provide a flow of respiratory gas to a patient in a predetermined manner in response to pressure fluctuations detected in the enclosure over a predetermined time period and based on the manner in which the respiratory gas is delivered to the patient. It is also clear that can be controlled.

While particular embodiments of the present invention have been described and illustrated, it will be apparent that many modifications and embodiments are possible within the capabilities of those skilled in the art and without affecting the effects of the present invention. Thus, it should be understood that various changes can be made in form, detail and application of the present invention without departing from the spirit and scope of the invention.

[Brief description of the drawings]

FIG. 1 is a schematic diagram of a ventilator control device. FIG. 2 is a detailed view of the ventilator control device. FIG. 3 is a graph of the air / oxygen mixture control of Example 1. FIG. 4 is a graph of the receiving tank pressure for spontaneous breathing (Example 2). FIG. 5 is a tank at the receiving tank pressure for a large mandatory breath (Example 3). FIG. 6 is a graph of the receiving tank pressure for a small mandatory breath (Example 4). 10 Ventilator controller, 12 Tank, 16 Oxygen inlet port, 17 Oxygen supply source, 18 Air inlet port, 19 Air supply source, 20 Oxygen supply conduit, 22 ... Air supply conduit, 24… Solenoid valve, 28… Outlet conduit, 30… Transducer, 32… Electronic control device, 35… Suction servo valve.

──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Paul Fenima United States of America 92028 Fallbrook Acacia Lane 1619 (72) Inventor Roger Gagne United States of America California 92009 Carlsbad Lavante Street 2773 (56) References Table 2-502520 (JP, A) (58) Field surveyed (Int. Cl. ⁷ , DB name) A61M 16/00 A61M 16/10

Claims (4)

(57) [Claims] 1. A ventilator device for intermittently delivering breathing gas to a patient, comprising: a pressure-encapsulated container having a rigid, fixed wall; and first and second inlet ports connected to the container. Each of the ports is in fluid communication with a separate first and second source of first and second respective component gases that are mixed in a desired proportion to form the breathing gas, wherein the component gases are initially known Having a ratio, wherein the first and second inlet ports have associated corresponding first and second inlet valves that can independently control the flow of the component gas through the inlet port to the vessel. The ventilator apparatus further comprises: outlet means for connecting the container to the patient in fluid communication, determining the start and completion of inhalation of the patient, and following the completion of inhalation of the patient, the respiratory gas in the enclosure. Pressure And a pressure transducer means for generating a differential pressure signal indicative of the rate of change of pressure in the sealed container over a period of time; and responsive to confirmation of completion of inhalation of the patient while the second inlet port is closed. And sequentially controlling the flow of the first component gas into the sealed container passing through the first inlet port, and passing through the second inlet port while the first inlet port is closed. An inlet valve flow control means for controlling the flow of the second component gas and controlling at a desired rate responsive to the gas pressure detected in the sealed vessel, wherein the vessel is controlled to a predetermined fill pressure. The desired pressure change of each component gas in the sealed container corresponding to the number of moles of each of the component gases required to be filled with a proportion of the component gas is determined by the total pressure in the container and the initial pressure of the component gas. Based on known ratio And a means for determining the actual ratio of the component gas in the breathing gas in the container based on the detected pressure change of the component gas introduced into the sealed container. Control means, electrically connected to the pressure transducer means, and following the initiation of suction, the outlet in a predetermined manner in response to a differential pressure signal based on a rate of change of gas pressure detected in the sealed container. A vent flow control means for the outlet means for controlling the flow of said breathing gas through said means. 2. The means for controlling valve flow for said outlet means responsive to a differential pressure signal from said pressure transducer means for determining a rate of outflow of breathing gas from said container;
Output comparing means for comparing the outflow speed with a predetermined reference outflow value and generating an error signal indicating a difference between the outflow speed and the predetermined reference outflow value; andthe error signal in fluid communication with the outlet means. And valve means operatively connected to said output comparing means for receiving said output signal and adapted to adjust said spill to said predetermined spill value in response to said error signal. Equipment. 3. The method of claim 2, wherein said inlet valve flow control means compares the gas pressure in said container with a predetermined threshold value in response to the gas pressure detected by said pressure transducer means. Filling control means configured to generate a fill signal when the pressure is below the threshold value, wherein the first and second inlet valve means are capable of receiving the fill signal. The apparatus of claim 1 operatively connected to the filling control means. 4. The flow control means for the inlet valve further comprises means for predicting the expected gas pressure in the container after the patient's next expected inhalation.
The apparatus of claim 1 including means for determining based on the detected rate of change of pressure in the vessel, and filling control means for comparing the predicted gas pressure to a predetermined pressure threshold.