JPH0141344B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention comprises a supply circuit for delivering breathable gas, a utilization circuit having an inspiratory branch and an exhalation branch with an exhalation valve, a breathable gas accumulator forming a reserve buffer, an inspiratory branch a distributor connected to the supply circuit, comprising an intake valve communicating with the airway, an accumulator valve and a check valve both communicating with the accumulator, and operating the intake valve, the exhalation valve and the accumulator valve according to a predetermined program; a cyclically actuated control device which directs the respirable gas coming from the supply circuit and the accumulator to the inspiratory path during the inspiration phase and the breathable gas coming from the supply circuit to the accumulator during the expiration phase; TECHNICAL FIELD The present invention relates to a breathing apparatus for artificially ventilating a user's pulmonary system according to a cycle of inspiratory and expiratory phases. Hereinafter such a breathing apparatus will be referred to as a breathing apparatus "of the type described above".

Respiratory devices of the type described above, in which breathable gas is stored during the exhalation phase and then returned to the utilization circuit during the inhalation phase, are primarily suitable for the treatment of respiratory insufficiency or decline and are available in hospital and domestic environments or as emergency equipment. It can also be used as

A periodically operating control device makes it possible to supply ventilation (i.e. a given volume of breathable gas per unit time) to the user and to control its parameters, in particular the frequency of the breathing cycle, the duration of inspiration and expiration and these The ratio between the inspiratory period and the expiratory period is displayed and can be changed arbitrarily.

Ventilation operations can therefore be easily varied and controlled by the person tasked with operating the breathing apparatus, usually a physician.

French patent entitled “Respiratory Apparatus”
No. 7,607,945 discloses a breathing apparatus of the type described above, which is arranged to automatically adapt to the demands of the lungs and the resistance of the user.

The radical exploration carried out in the field of artificial ventilation has revealed a number of special problems occurring in medical technology, which the drawbacks of certain existing devices are unable to overcome. These problems arise primarily in two cases: (a) when the ventilation controlled by the operator becomes insufficient for the patient; and (b) when the patient's pulmonary system is obstructed, e.g. during the procedure. Encountered when ventilation becomes excessive for the patient.

It is an object of the present invention to substantially eliminate or reduce these problems. Therefore, although the breathing apparatus according to the present invention is of the type described above,
An auxiliary replenishment circuit for supplying an increment of breathable gas to the utilization circuit;
and a vent correction circuit for sensing changes in pressure within the intake passageway. The vent correction circuit may, on the one hand, initiate a premature inhalation phase and supply of breathable gas to the accumulator when a negative pressure is detected, or, on the other hand, when an abnormal pressure rise is detected. , configured to initiate a premature exhalation phase and release of breathable gas from the accumulator.

The directional device according to the invention thus makes it possible to virtually automatically increase or decrease the ventilation as a function of the pressure in the utilization circuit depending on the patient (i.e. his reaction and condition).

According to another feature of the invention, the aforementioned auxiliary replenishment circuit consists of a duct with a solenoid valve and a calibrated orifice connecting the supply circuit to the accumulator.

A supplementary supply of breathable gas to the utilization circuit is thus provided via the accumulator at a constant flow rate, the value of which flow rate being a function of the calibrated orifice and the opening period of the solenoid valve.

According to a further characteristic of the invention, said discharge circuit consists of a passageway for escape to the outside air which communicates with the accumulator and is equipped with a solenoid valve.

The discharge of the excess volume of breathable gas is thus effected from the accumulator in a variable manner by means of the solenoid valve.

In order to further clarify the invention, reference will now be made to the drawings in which certain embodiments of the invention are shown by way of example in conjunction with illustrative graphs.

Referring to the drawings, it is clear from FIG. 1 in particular that the pressure in the utilization circuit, i.e., the circuit on the patient's side, is the value taken as the starting point (residual lung pressure) during the inflow or inspiration phase, i.e., time period I. to the maximum pressure P and then falls to the starting point value during the exhalation or outflow phase or time period E, the sum of both periods being the respiratory period or period T (I+E=T). The pressure in the utilized circuit cannot exceed the safety value Ps in all cases, and this is due to the safety value being incorporated into the circuit. The values I, E, T and the volume of gas inspired are controlled by the operator in such a way as to adapt them to the needs and characteristics of the patient. The value of P is the result of this control operation. The corresponding breathing cycles are shown in FIGS. 1 and 2.

When ventilation becomes insufficient as the patient's characteristics change, the patient responds by changing the expiratory phase, the point A when he completes exhalation, and the starting point B of the subsequent inspiratory phase imposed by the breathing apparatus. The patient begins to try to inhale between the two. This inspiratory effort creates a negative pressure in the patient side circuit between A and B, which manifests as insufficient ventilation (cycles 3 and 4).

FIG. 2, in which the same parameters as in FIG. 1 are designated by the same symbols, relates to the case of a patient with an obstructed pulmonary system.
Pressure increases significantly in the patient-side circuit during the first cycle. This is manifested by an increase in the energy level in the accumulator and also by an increase in pressure, which continues with each cycle until this reaches the safe pressure value Ps (cycle 4). The ventilation provided by the breathing apparatus becomes excessive.

According to the embodiment illustrated in FIG. 3, the breathing apparatus according to the invention essentially comprises a circuit 10 for supplying breathable gas, a distributor block 20, a utilization circuit or patient-side circuit 30, a gas pressure accumulator. 40 (this circuit 30 and the accumulator 40 receive breathable gas from the circuit 10 via the distributor 20), and a periodically actuated electrical control device 5.
0, the electronic controller 50 has the task of varying the successive inspiration and expiration cycles to ensure patient breathing.

The supply circuit 10 includes two pressurized gas sources 11 and 1
2, and these gas sources are, for example, an air source and an oxygen source if the patient is to be forced to breathe with oxygen-rich air.

Gas sources 11 and 12 are connected to tubes 110 and 120
via a pressure equalizer 13, which in turn communicates via tubes 130 and 131 to a mixer 14, which is equipped with a control handle 140 for regulating the mixing of the two gases.

The mixer 14 communicates via a pipe 15 with a pressure regulator 16, which is connected to a flow meter 17 and a flow control valve 18.
to restore the gas pressure to a stable value of the order of 1 bar.

The distributor 20 has an injector 2 connected to the tube 15.
10, the venting part 211 of which opens directly into the interior space 200 of the distributor. The internal space 200 communicates with the utilization circuit 30 via the intake valve 22 housed in the compartment 201.
and on the one hand via an accumulator valve 23 housed in a compartment 202 communicating with a passage 203 and on the other hand (gas from the accumulator 40 to the circuit 3).
0) through a check valve 24 to the accumulator 40 and finally to outside air through a supplementary air or vent valve 25. The compartment 201 communicates with the outside air via a calibrated valve 26 to ensure that the pressure within the circuit 30 does not exceed a safety value Ps.

The intake valve 22 includes a valve seat 220 and a gas pressure valve body 22.
1, and the pneumatic valve body 221 is connected to a solenoid valve 223 via a pipe 222. This solenoid valve serves to "inflate" and "deflate" the pneumatic valve body, for which purpose it communicates on the one hand via a tube 224 with the outlet of the divergent part 211 of the ventilator tube 21 and on the other hand via a tube 226. It communicates with the compartment 201 of the distributor 20.

The accumulator valve 23 has a valve seat 230 and a pneumatic valve body 231, which communicates via a pipe 232 with a solenoid valve 233 for raising and lowering the accumulator valve. The solenoid valve 233 is connected to the regulator 235 on one side.
It communicates with the pipe 15 via a pipe 234 provided with an air vent, and communicates with the outside air via an air bleed section 236 on the other hand.

The utilization circuit 30 has an inhalation branch 31 and an exhalation branch 32 which communicate directly with the compartment 201 of the distributor 20, both branches 31 and 32 having a common main channel 3.
3 to a mask 34 for the patient.
Shunt 31 has a bacterial filter 35 and a humidifier 36. The exhalation channel 32 communicates with the outside air via an exhalation valve 37. The exhalation valve 37 has a valve seat 370 and a gas pressure valve body 371, and this gas pressure valve body communicates via a pipe 372 with a solenoid valve 373 for raising and lowering the exhalation valve 37. The solenoid valve 373 is connected on the one hand to the divergent part 211 via a pipe 374 and said pipe 224 of the intake valve.
on the other hand, and communicates with the outside air via an air bleed section 376.

The accumulator 40 has an elastic bag 41, called a supplementary bag, arranged to store a portion of the breathable gas, thus achieving a reserve buffer, which is connected to the distributor via a tube 42 fitted with a safety valve 43. 20.

The control device 50 essentially consists of an electronic clock or timer 51 and a control element 52, which control element is formed, for example, by a power amplifier and connected to a conductor 51.
2 and 513 by the clock. The control device 50 is arranged to control the frequency 1/I+E of the breathing cycle and the ratio I/E of the inspiratory period to the expiratory period in each breathing cycle according to a preset program, and this frequency and ratio are determined by e.g. control elements 510 and 511 formed by a clock 51 and synchronized with the clock 51;
They can be adjusted individually. The control element 52 is connected to the solenoid valve 223 via a conductor 520 and to the solenoid valves 233 and 37 via a common conductor 521.
3 and arranged to send a signal to the solenoid valve based on a drive signal received from clock 51. This achieves the operation of opening and closing the electromagnetic valves and thus the gas pressure valves 22, 23 and 37.

Thus, the operator can provide a specific sequence of inspiration and expiration periods to the patient.

The breathing apparatus according to the invention includes an auxiliary supplementary or intake circuit 60 separate from the components described above;
A discharge circuit 70 and a ventilation correction device 80 are provided.

The auxiliary replenishment circuit 60 essentially consists of a tube 61 with a solenoid valve 62 and a calibrated orifice 63 operating according to the "all or nothing" principle. The tube 61 establishes an articulated connection between the tube 15 of the supply circuit 10 and the tube 42 of the accumulator 40 .

The discharge circuit 70 consists of a vent pipe 71 connected to the interior space 200 of the distributor 20 and equipped at one end with a solenoid valve 72 operating on the "all or nothing" principle.

The draft correction device 80 consists of a pressure sensor or pick-up 81, an electronic computer 82 for sensing the readings of the pick-up, and a control element 83 driven by the computer.

The pick-up 81 can be of the piezoresistive type, for example, and is connected to the intake channel 31 by a tube 810 with a pressure gauge 811. It detects the pressure in this shunt and supplies a voltage proportional to this pressure to the calculator 82 via electrical conductor 812.

Calculator 82 triggers clock 51 when the pressure in shunt 31 reaches a preset minimum value Pm (negative pressure) or a preset maximum value (which is less than or at most equal to the safety pressure Ps). starts the inhalation phase or the exhalation phase too early (i.e. those phases that precede the inhalation phase and the exhalation phase as would normally occur according to the program defined by the control elements 510 and 511). The clock 51 is configured to be controlled by the clock 51. In fact, elements 510 and 511 establish the frequency of the breathing cycle, 1/I+E, and the ratio of the inspiratory and expiratory periods, I/E, and thus determine I and E. As a result of the activation of the inspiratory or expiratory phase beforehand, the expiratory or inspiratory period of the programmed breathing cycle is shortened and these two periods thus have values Er and Ir lower than E and I.
I take the.

Calculator 82 is also arranged to store periods I and E, and calculates the differences E-Er and I-Ir in such a way as to control the opening and closing of valves 62 and 72 as a function of the time differences E-Er and I-Ir. arranged so as to establish the

Calculator 82 converts the voltage supplied by pickup 81 into two reference voltages, one of which is the minimum pressure.
The minimum voltage corresponding to Pm and the other is the maximum voltage
two comparator circuits 820a and 820b for comparison to the maximum voltage corresponding to PM)
has. These two reference voltages and thus the two pressures Pm and PM are applied to a control element 8 formed, for example, by a potentiometer and connected to one of the input terminals of each comparator via conductors 822a and 822b.
21a and 812b, the operator can arbitrarily select (under the condition that PM<Ps). Comparator 8
The other terminals of 20a and 820b are connected to the output terminal of pickup 81 via conductor 812;
The output terminals of these comparators are conductors 823a and 8
23b to the time base of clock 51 (not shown).

The calculator 82 also includes two storage circuits 824a and 824b and two subtraction circuits 826a and 82.
It has 6b. Circuits 824a and 824b receive at their inputs the periods I and E programmed by clock 51 and store them.

These periods I and E are connected to a circuit of a clock 51 (not shown) on conductor 5, which receives initial commands from the operator regarding the breathing frequency 1/I+E and the ratio I/E.
Computation element 8 connected by 14 and 515
25, calculation element 825 calculates the values and exact data of inspiratory period I and expiratory period E, which are calculated by conductors 825a and 82
5b to storage circuits 824a and 824b. Subtraction circuits 826a and 826b are
On the one hand, via conductors 827a and 827b we receive the exact times of occurrence of the initially calculated periods I and E, and on the other hand, conductor 828
The exact times of occurrence of periods Ir and Er are received from comparators 820a and 820b via a and 828b.

The difference signal between the end of the actual expiration period Er and the normal end of the set expiration period E is
29a to the control element 83. Alternatively, the difference signal between the end of the actual inspiratory period Ir and the normal end of the set inspiratory period I is transmitted to conductor 829.
b to the control element 83.

Control element 83 includes two amplifiers 830a and 8
30b, and their input terminals are connected to the subtraction circuit 826 via the conductors 829a and 829b mentioned above.
a and 826b, and the output terminal is connected to conductor 8
Solenoid valves 62 and 72 via 31 and 832
, which actuate the opening and closing of these solenoid valves as a function of signals received from subtraction circuits 826a and 826b.

The operation of the distributor described above is as follows.

Valves 22, 37 controlled by control device 50
and 23 give rise to an inspiratory or expiratory cycle depending on whether they are opened or closed. During inspiration (as shown in FIG. 3), valve 22 is open and valves 23 and 37 are closed. Breathable gas coming from the supply circuit 10 through the vent tube 21 and from the bag 41 via the check valve 24 is transferred to the interior space 20 of the distributor 20.
0, go into the compartment 201 and then go to the circuit 30 to be used.
Proceed into branch 31. During exhalation, valve 22 is closed and valves 23 and 37 are opened. The gas exhaled by the patient passes through the exhalation channel 32 and the valve 37 into the outside air, while the breathable gas coming from the supply circuit 10 via the ventilator tube 21 passes from the interior space 200 to the compartment 202 and into the passage 203. and tube 4
2 and into the bag 41. Thus, if the ventilation provided to the patient is consistent with the requirements and characteristics of the patient's lungs in terms of frequency and volume, in other words if this ventilation occurs according to cycles 1 and 2 of FIGS. is the supplementary circuit 60
The solenoid valve 62 in tune with the discharge circuit 70 and the solenoid valve 72 in tune with the discharge circuit 70 are held closed by a correction circuit 80.

When the patient makes an inspiratory effort and the ventilation becomes insufficient, a negative pressure is created in the shunt 31 of the utilization circuit, which corresponds to A' in FIG. 5 (this corresponds to point A in FIG. 1). appears in This negative pressure sensed by pickup 81 is proportionally converted to voltage, which is received by comparators 820a and 820b. This voltage is applied to control elements 821a and 821
compared with a reference voltage preset by b,
As soon as this reaches the reference voltage corresponding to Pm set by 821a, comparator 820a sends an electrical signal via conductor 823a to clock 51 and via conductor 827a to subtractor 826a. Clock 51 drives control element 52 for starting the premature intake phase. The exhalation phase is therefore shortened by the device 50 to an actual value Er, which is shorter than the preset breathing period E. Subtractor 826a calculates the stored expiratory period E to occur.
Determine the difference between the expiratory period Er and the actual expiratory period Er. The difference between these two periods causes the subtractor 826a to actuate the solenoid valve 62 to open the solenoid valve 62 via the amplifier 830a during the period E-Er=Ia to supply supplemental breathable gas to the bag 41.
be supplied to The energy level in the bladder 41 increases, which means an increase in the inspiratory flow rate. Venting is thus accomplished according to cycles 3 and 4 of FIG. Cycle 4 overlaps cycle 3 and its peak pressure exceeds the value P of the previous cycle.

Conversely, if the patient's pulmonary system is obstructed, resulting in excessive ventilation, this will increase the pressure in the utilization circuit. pick up 8
This pressure detected by 1 is proportionally converted into an electrical signal, which is transmitted by comparators 820a and 820b.
received by. As soon as this voltage reaches the reference value corresponding to PM preset by 821b, comparator 820b sends an electrical signal to conductor 823.
b to clock 51 and conductor 827b.
to subtractor 826b. Clock 51 drives control element 52 to initiate the premature exhalation phase. The inspiratory phase is therefore reduced by the device 50 to an actual value Ir which is shorter than the inspiratory period I preset. Subtractor 826b also determines the difference between the stored inspiration period I to occur and the actually occurred inspiration period Ir. The difference between these two periods causes the subtractor 826b to operate via the amplifier 830b to open the solenoid valve 72 for the period I-Ir=V, thereby causing the storage in the bag 41 to occur. A portion of the breathable gas that was present is released to the outside, thereby causing its partial decompression. The energy level in bladder 41 decreases and therefore the inspiratory flow rate decreases as well.

The inspiration and expiration cycles thus take the form shown by cycles 3 and 4 in FIG. The peak pressure in cycle 3 reaches the value PM, but the peak pressure in cycle 4 returns to a value lower than PM due to the vacuum in the bag 41.

Variations may be made in the arrangement of the embodiments described and illustrated without departing from the spirit of the invention.

[Brief explanation of drawings]

1 is a graph showing the pressure p in the utilization circuit of a known type of breathing apparatus as a function of time t when the ventilation provided by this apparatus becomes insufficient; FIG. 2 is given. A graph similar to FIG. 1 regarding the case of excessive ventilation, FIG. 3 is a diagram of the breathing apparatus according to the invention, FIG. 4 is a detailed enlarged view of the ventilation correction device, and FIG. FIG. 6 is the same graph as FIG. 1 plotted for the breathing apparatus according to the invention, and FIG. 6 is the same graph as FIG. 2 plotted for the breathing apparatus according to the invention. In the drawing, 10 is a supply circuit, 20 is a distributor, 22 is an intake valve, 23 is an accumulator valve, 2
4 is a check valve, 30 is a utilization circuit, 31 is an intake path,
32 is an exhalation branch, 37 is an exhalation valve, 40 is an accumulator, 50 is a control device, 60 is a supplementary circuit, 61
is a connecting pipe, 62 is a solenoid valve, 63 is an orifice, 7
0 is a discharge circuit, 71 is a bleed pipe, 72 is a solenoid valve, 8
0 is a ventilation correction device, 82 is an electronic computer, 820 is a comparison circuit, 824 is a storage circuit, and 826 is a subtraction circuit.

Claims (1)

[Claims] 1. A supply circuit for delivering breathable gas, a utilization circuit having an inhalation path and an exhalation path with an exhalation valve;
a respirable gas accumulator forming a reserve buffer, a distributor connected to the supply circuit, comprising an inlet valve communicating with the intake path and an accumulator valve and a check valve both communicating with the accumulator; and a predetermined program. According to the intake valve,
It has a periodically actuated controller for controlling an exhalation valve and an accumulator valve, which controller directs the breathable gas coming from the supply circuit and the accumulator to the inspiratory path during the inspiratory phase and directs the respirable gas coming from the supply circuit and the accumulator to the inspiratory path during the exhalation phase. In a breathing apparatus for ventilating the pulmonary system of a user according to a cycle of inspiratory and expiratory phases, the supplementary respirable gas is arranged to direct the respirable gas coming from the supply circuit to the accumulator. an auxiliary replenishment circuit for supplying gas to the utilization circuit, a discharge circuit for withdrawing a portion of the breathable gas from the utilization circuit, and a vent correction circuit for sensing changes in pressure within said inspiratory channel. further comprising, on the one hand, initiating a premature inhalation phase and supplying breathable gas to the accumulator when a negative pressure is detected;
or on the other hand, a breathing apparatus characterized in that it is configured to initiate a premature exhalation phase and release of breathable gas from the accumulator when an abnormal pressure increase is detected. 2. A breathing apparatus according to claim 1, wherein the auxiliary replenishment circuit consists of a connecting tube with a solenoid valve and a calibrated orifice connecting the supply circuit to the accumulator. 3. The breathing apparatus according to claim 1, wherein the discharge circuit comprises a relief pipe communicating with the accumulator and equipped with a solenoid valve. 4. The auxiliary replenishment circuit consists of a connecting pipe having a solenoid valve and a calibrated orifice and connecting the supply circuit to the accumulator, and the discharge circuit consists of a relief pipe communicating with the accumulator and having a solenoid valve, 2. The breathing apparatus of claim 1, wherein tubes communicate with the accumulator upstream and downstream, respectively, of the check valve for directing the flow of gas from the accumulator to the inspiratory shunt. 5. a pressure pick-up, in which the vent correction device is arranged to supply an electrical signal in dependence on the pressure in the intake channel, an electronic computer connected to the pick-up and said cyclically actuated control device;
5. The respiratory apparatus according to claim 4, further comprising a control element arranged to open and close the electromagnetic valve driven by the computer. 6. Claim 5, wherein the pressure pickup is of the piezoresistive type and is arranged to deliver a voltage proportional to the pressure received from the intake channel.
Respiratory apparatus as described in Section. 7. An electronic computer comprises a comparator circuit having a number of input terminals, one of which is connected to a pickup and another input terminal arranged to supply two reference voltages, a minimum value and a maximum value. the comparator circuit is connected to a control element which controls said periodic actuation so as to actuate the start of the inhalation phase or expiration phase when the voltage supplied by the pickup reaches said maximum or minimum value. 7. The breathing apparatus according to claim 6, which drives a control device for the breathing apparatus. 8. The calculator comprises a memory circuit for storing the inspiratory period and expiratory period preset by the control device, and a subtraction circuit having many input terminals, one input terminal of the subtraction circuit is , connected to the storage circuit, and another input terminal of the subtracter is
connected to said comparator circuit for delivering an inspiratory and expiratory period shorter than said inspiratory and expiratory periods resulting from triggering of said control device in dependence on said minimum and maximum reference values; The circuit determines the period of opening of the solenoid valve in dependence on the difference between the preset inspiratory period and the short inspiratory period and the difference between the preset expiratory period and the short expiratory period. 8. The respiratory apparatus of claim 7, wherein the control device is actuated to control. 9. The respiratory device according to claim 8, wherein the control device comprises an amplifier circuit having a number of input terminals connected to the subtraction circuit and a number of output terminals connected to the solenoid valve. Device.