U.S. patent application number 10/899022 was filed with the patent office on 2005-02-24 for device and process for supplying respiratory gas under pressure or volumetrically.
Invention is credited to Andrieux, Claude.
Application Number | 20050039748 10/899022 |
Document ID | / |
Family ID | 33523015 |
Filed Date | 2005-02-24 |
United States Patent
Application |
20050039748 |
Kind Code |
A1 |
Andrieux, Claude |
February 24, 2005 |
Device and process for supplying respiratory gas under pressure or
volumetrically
Abstract
A device for supplying respiratory gas to a patient according to
respiratory cycles, includes a gaseous flow rate generator provided
with a turbine with low inertia and high nominal speed, a first
supply circuit for the gaseous flow toward a respiratory mask or an
intubation elements of the patient, elements for measuring pressure
and/or measuring flow rate of the gaseous flow, the computation
elements for parameters of pressure and/or flow rate, and elements
for controlling the speed of rotation of the generator. The
measuring elements, the computation elements and the speed control
elements coact automatically to control the speed of rotation of
the turbine as a function of the inspiration and expiration phases
and as a function of patient pressure signals and/or inspiration
flow rate signals.
Inventors: |
Andrieux, Claude; (Baudreix,
FR) |
Correspondence
Address: |
YOUNG & THOMPSON
745 SOUTH 23RD STREET
2ND FLOOR
ARLINGTON
VA
22202
US
|
Family ID: |
33523015 |
Appl. No.: |
10/899022 |
Filed: |
July 27, 2004 |
Current U.S.
Class: |
128/204.22 ;
128/204.18; 128/204.21; 128/205.24 |
Current CPC
Class: |
A61M 2205/42 20130101;
A61M 16/205 20140204; A61M 16/10 20130101; A61M 16/206 20140204;
A61M 16/208 20130101; A61M 2016/0039 20130101; A61M 2016/0021
20130101; A61M 2016/0042 20130101; A61M 16/0069 20140204; A61M
16/107 20140204 |
Class at
Publication: |
128/204.22 ;
128/204.18; 128/204.21; 128/205.24 |
International
Class: |
A61M 016/00 |
Foreign Application Data
Date |
Code |
Application Number |
Jul 29, 2003 |
FR |
03 09347 |
Claims
1. Device (1) for supplying respiratory gas to a patient according
to respiratory cycles, comprising a gas flow generator (2) provided
with a turbine (2a) with low inertia and high nominal speed, a
first circuit (3) called a circuit for supplying a gaseous flow to
a respiratory mask (4) or to an intubation means of the patient,
means (5, 6, 7, 8) for measuring the pressure and/or flow rate of
the gaseous flow, means (9) for computing parameters of pressure
and/or flow rates and means (10) for controlling speed of rotation
of the generator, characterized in that the measuring means (5, 6,
7, 8), the computation means (9) and the means (10) for controlling
the speed coact automatically to control the speed of rotation of
the turbine (2a) as a function of the inspiration and expiration
phases and as a function of the patient pressure signals and/or
inspiration flow rate signals.
2. Device according to claim 1, characterized in that the pressure
measuring means comprise a sensor (6) of patient pressure and/or a
sensor (7) of expiration valve pressure.
3. Device according to claim 1, characterized din that the flow
rate measuring means comprise a sensor (7) of inspiration flow rate
disposed adjacent the outlet of the generator (2).
4. Device according to claim 1, characterized in that it comprises
a passive member (12) for generation of a pressure drop in the
supply circuit.
5. Device according to claim 4, characterized in that this passive
member (12) is a non-return flap if desired associated with a
passive flap (13) for the addition of external air downstream of
the non-return flap in the supply circuit (3).
6. Device according to claim 1, characterized in that it comprises
a second circuit (16) comprising a proportional electro-valve (15),
for controlling an expiration valve (14) that is part of a third
circuit (11) by application of a counter-pressure to this valve
(14), control means of said proportional electro-valve (15) being
coupled to the computation means (9).
7. Device according to claim 1, characterized in that the means for
measuring flow rate comprise an expiration flow rate sensor (8) in
the third circuit (11) so-called patient return circuit.
8. Process for supplying a respiratory gas according to respiratory
cycles, comprising inspiration and expiration phases, by means of a
device according to claim 1, characterized in that the measuring
means (5, 6, 7, 8) and the computation means (9) act on the speed
control means (10) so as automatically to control the speed of
rotation of the turbine (2a) as a function of pressure and/or
volume standards, of the detection of the inspiration and
expiration phases, of patient pressure signals and/or inspiration
flow rate signals, the supplying of the respiratory gas taking
place as to pressure and/or as to volume.
9. Process according to claim 8, characterized in that it comprises
phases of pressure increase with increase slopes of pressure
produced by acceleration of the turbine (2a).
10. Process according to claim 8, characterized in that the
transition between an inspiration phase and an expiration phase is
carried out by controlled deceleration of the turbine (2a).
11. Process according to claim 8, characterized in that during
expiration phases, an expiration valve (14) which is part of a
third circuit (11) connected to the mask (4) or to the incubation
device, is controlled, via a proportional electro-valve (15) and a
second circuit (16), by a regulation member of the pressure in the
first circuit (3).
12. Process according to claim 11, characterized in that the
computation means and the control means of the speed of rotation of
the generator adapt the speed of the turbine (2a) as a function of
a threshold of this expiration pressure beyond a regulated loss, by
the expiration valve (14), so as to create a rinsing flow rate in
the first circuit.
13. Process according to claim 8, characterized in that during
phases of insufflation corresponding to the inspiration phases, an
expiration valve (14), which is part of a third circuit (11)
connected to the mask (4) or to the intubation device, is
controlled via a proportional electro-valve (15) and by a second
circuit (16), according to pressure.
14. Process according to claim 8, characterized in that it
comprises a measurement of expiration flow rate and a measurement
of inspiration flow rate.
15. Device (1) for providing a respiratory gas to a patient
according to respiratory cycles, comprising a gas flow generator
(2) provided with a turbine (2a) for flow inertia and high nominal
speed, a first circuit (3) called a circuit for supplying gaseous
flow toward a respiratory mask (4) or an intubation means of the
patient, means (5, 6, 7, 8) for measuring pressure and/or of flow
rate of the gaseous flow, computation means (9) of parameters of
pressure and/or flow rate, and means (10) for controlling the speed
of rotation of the generator, characterized in that the measuring
means (5, 6, 7, 8), the computation means (9) and the speed control
means (10) coact automatically to control the speed of rotation of
the turbine (2a) as a function of the inspiration and expiration
phases and as a function of the patient pressure signals and/or
inspiration flow rate signals, and in that the control system of
the generator carries out phases of pressure increase with
increasing slopes of pressure by means of acceleration of the
turbine (2a), the supply of respiratory gas taking place according
to pressure or according to volume.
16. Device according to claim 15, characterized in that the control
system of the generator carries out the transition between an
inspiration phase and an expiration phase by means of controlled
deceleration of the turbine (2a).
17. Device according to claim 15, characterized in that the control
system of the generator comprises means permanently adjusting the
insufflation pressure between a low pressure threshold and a
maximum pressure threshold so as to maintain the inspiration
current volume as near as possible to a predetermined target
volume.
18. Device according to claim 15, characterized in that it
comprises a proportional electro-valve (15), a second circuit (16)
and an expiration valve (14), the proportional electro-valve (15)
and the second circuit (16) being arranged to control the
expiration valve (14) with a pressure regulating member of the
first circuit (3) during expiration phases.
19. Device according to claim 15, characterized in that computation
means and the means for controlling the speed of rotation of the
generator are arranged to adapt the speed of the turbine (2a) as a
function of an expiration pressure threshold beyond a loss
regulated by an expiration valve (14) so as to create a rinsing
flow rate in the first circuit during expiration phases.
20. Device according to claim 18, characterized in that the
proportional electro-valve (15) and the second circuit (16) are
arranged to control the expiration valve (14) according to pressure
during insufflation phases corresponding to the inspiration phases.
Description
[0001] The present invention relates to a device and process for
supplying respiratory gas.
[0002] Devices for supplying respiratory gas are used particularly
in the treatment of respiratory ailments of adult or infant
patients.
[0003] Such devices are adapted to supply a quantity of air, if
desired with added oxygen, either in the form of a quantified
breathable volume, or in the form of a first predetermined pressure
called inspiration pressure and a second predetermined pressure
called expiration pressure.
[0004] WO 00/24447 relates to a device for supplying respiratory
gas provided with a compressor delivering a flow of gas under
pressure to a patient through a downstream accumulator/silencer and
a flow rate regulating valve. According to this document, the
surplus of unneeded gas is returned to an upstream
filter/accumulator through a bypass valve so as to limit the loss
of respiratory gas.
[0005] FR 2 663 547 A1 relates to apparatus for continuously
providing an overpressure of respiratory gas; this apparatus using
a high speed turbine supplying gas under constant predetermined
pressure regulated by measuring the pressure at the respiratory
mask of the patient. This apparatus is passive in that the pressure
is maintained continuously, the expiration phases being possible
thanks to a calibrated loss at the respiratory mask of the
patient.
[0006] FR 2 822 384 A1 in the name of the applicant relates to a
mixed pulmonary ventilator provided with a flow generator, the
circulation means permitting re-injecting the flow upstream of the
generator during an expiration phase of the patient, the
circulation means comprising particularly a regulating valve
comprising two flaps actuated by the same actuator permitting
several modes of regulation and an optimization of the flow as a
function of the inspiration and expiration phases. According to
this document, the speed of rotation of the generator is maintained
constant, the pressure in the patient circuit being controlled by
the two flaps which permit return of the gas to the generator
particularly during the expiration phases.
[0007] It remains that the circuits and systems necessary to
provide and to regulate the levels of pressure and/or volumetric
quantities of respiratory gas, are complicated and cumbersome, the
control of the flaps and valves being sensitive.
[0008] The present invention seeks to provide a device for
supplying respiratory gas, that is improved in that its operation
uses an automatic control of the turbine for the inspiration and
expiration phases and does not use a return system for gas upstream
of the turbine, thereby simplifying the system, whilst permitting
operation with a sealed circuit at the respiratory mask or of the
intubation device of the patient during the inspiration phases and
the loss during the expiration phases.
[0009] To this end, the present invention relates to a device for
supplying respiratory gas to a patient according to respiratory
cycles, comprising a gas for a generator, a circuit for bringing
the gaseous flow to a respiratory mask or intubation device of the
patient, means for measuring the pressure and/or for measuring the
gaseous flow rate, means for computing the parameters of pressure
and/or flow rate and control means of the speed of rotation of the
generator, in which device the measuring means act on the speed
control means through computer means so as automatically to control
the speed of rotation of the turbine as a function of the
inspiration and expiration phases as a function of patient pressure
signals and/or inspiration flow rate signals.
[0010] The pressure measuring means can particularly comprise a
patient pressure sensor and/or an expiration valve pressure
sensor.
[0011] The flow rate measuring means can particularly comprise an
inspiration flow rate sensor disposed adjacent the outlet of the
generator.
[0012] The flow rate measuring means can comprise an expiration
flow rate sensor in a patient return circuit.
[0013] In a particular embodiment, the device can comprise a
passive member for generating a pressure drop in the supply
circuit. This passive member can particularly be a non-return flap
if desired associated with a passive flap for admission of external
air downstream of the non-return flap in the supply circuit.
[0014] According to a particular embodiment of the invention, the
device comprises an expiration circuit provided with an expiration
valve and a proportional electro-valve for controlling said
expiration valve by application of a counter-pressure.
[0015] The invention relates moreover to a process for providing a
respiratory gas according to respiratory cycles, comprising
inspiration and expiration phases, according to which said
measurement means and said computing means act on said speed
control means so as automatically to control the speed of rotation
of the turbine as a function of the pressure and/or volume
standards, of the detection of the inspiration and expiration
phases, of patient pressure signals and/or inspiration flow rate
signals, the supply of the respiratory gas taking place as to
pressure or as to volume.
[0016] The process can preferably comprise phases of pressure
increase with pressure increase slopes effected by acceleration of
the turbine.
[0017] More particularly, the transition between an inspiration
phase and an expiration phase can be effected by controlled
deceleration of the turbine.
[0018] The process can comprise, during expiration phases, a
control of an expiration valve with a pressure regulating member of
the first circuit, via a proportional electro-valve which is part
of a second circuit, the valve being a part of a third circuit
connected to the mask or to the intubation device.
[0019] Preferably, the computing means and the control means of the
speed of rotation of the generator can adapt the speed of the
turbine as a function of an expiration pressure threshold beyond a
regulated loss by the expiration valve so as to create a rinsing
flow rate in the first circuit.
[0020] More particularly, during insufflation phases corresponding
to the inspiration phases, an expiration valve, which is a part of
a third circuit connected to the mask or to the intubation device,
can be controlled for following the pressure through a proportional
electro-valve and a second circuit.
[0021] In a particular embodiment, the process can comprise a
measurement of expiration flow rate and a measurement of
inspiration flow rate.
[0022] Other advantages and characteristics of the invention will
become apparent from a reading of the description which follows, of
a non-limiting example of the invention, with reference to FIG. 1,
which is a schematic view of a device for supplying respiratory gas
according to the invention.
[0023] The device 1 for supplying respiratory gas or ventilation
device according to FIG. 1, comprises a generator 2 of gaseous flow
provided with a turbine 2a of low inertia and high rated speed.
This gaseous flow generator is disposed in a chamber 20, preceded
by a filter 21 for ambient air inlet, by an upstream and downstream
sound deadening means 22 and 23. The turbine 2a is for example a
turbine with a maximum speed of rotation of the order of 50,000
rpm, adapted to supply a pressure of 70 millibar above ambient and
a flow rate of the order of 200 l/min.
[0024] The air flow generator, thus comprises a micro-turbine with
low inertia, driven by an electric motor, controlled by a computer
or a computer means 9 so as to provide a wide range of flow rates
and pressures.
[0025] At the outlet of the chamber 20, the generator is connected
to a first circuit 3 called a circuit for supplying gaseous flow
toward a respiratory mask 4 or a intubation device (not shown) of
the patient.
[0026] The generator is controlled by control means 10 in the form
of an electronic control card connected to a supply 24 and to
computer means 9 in the form of an electronic card with a
microprocessor provided with control software and connected to a
control interface 25 with a screen and a keyboard.
[0027] So as to control the operation of the device and to cause it
to operate, the computer means are connected to means 5, 6, 7, 8
for measuring the pressure and/or for measuring the flow rate of
the gaseous flow in the form of sensors.
[0028] The sensor 6 is a pressure sensor connected to a first
circuit 3 which is a circuit for supplying gas to the mask 4 or
intubation device of the patient.
[0029] According to the example, a sensor 6 is disposed in the
apparatus 1 and connected to the mask 4 or to the intubation device
via a tube 6a.
[0030] The sensor 5 is a pressure sensor connected to a second
circuit 16 comprising a proportional electro-valve 15 whose
operation will be described later.
[0031] The sensor 7 is an inspiration flow rate sensor disposed in
the first circuit, in a laminator 26 controlling the flow of gas
leaving the generator.
[0032] An expiration flow rate sensor 8, in the third circuit 11
called patient return circuit, completes the measurement means.
[0033] The computation means 9 controls the members such as the
generator and the proportional electro-valve 15 as a function of
standards entered into the interface 25 as a function of the
ventilation programs and as a function of the pressure and/or flow
rate parameters from the sensors.
[0034] According to the invention, the measuring means 5, 6, 7, 8,
the computing means 9 and the speed control means 10 coact in the
first instance automatically to control the speed of rotation of
the turbine 2a as a function of the inspiration and expiration
phases and as a function of the patient pressure signals and/or
inspiration flow rate signals.
[0035] So as to regulate the output flow of the generator, the
device according to FIG. 1 comprises a passive member 12 for
generating a pressure drop in the supply circuit in the form of a
non-return flap 12 mounted in the first circuit 3. Thanks to this
member, the pressure on the generator side is always slightly
greater than the pressure in the circuit 3 on the mask supply side
or intubation device, which permits among other things a better
regulation of the operation of the device.
[0036] Downstream of this non-return valve 12, the circuit 3
comprises a passive flap 13 for the admission of external air. This
flap permits limiting the inspiration force of the patient by
spontaneous respiration through the machine when the latter is not
in operation.
[0037] On the mask side 4 or the intubation device after the
circuit 3 for supplying gas, is located a third circuit 11 called
an expiration circuit. This expiration circuit comprises an
expiration valve 14 with a membrane permitting opening a passage
either directly to the exterior or through tubing 11a toward a
laminator 27 and an air outlet 28.
[0038] To the valve 14 is connected the second circuit 16 provided
with proportional electro-valve 15 of the three-way type. This
electro-valve 15 receives along a first path a pressure outlet of
the generator, comprises a second path to vacuum and is connected
by a third path to the valve 14.
[0039] The electro-valve permits controlling the valve 14 by
applying a counter-pressure which closes the valve or limits its
opening such that the expiration pressure will remain higher than
the pressure of the second circuit 16. To release the valve 14, the
electro-valve is controlled such that the pressure of the generator
will be blocked, the second path of the free air being placed in
communication with the third path.
[0040] Thus a controlled expiration device is constructed about the
expiration valve 14 controlled by the electro-valve valve 15
connected to the flow generator, this electro-valve valve 15
permitting sending a portion of the generated flow to the
expiration valve so as to oppose its opening.
[0041] The proportional electro-valve 15 is controlled by control
means coupled to the computation means 9 and according to the
example disposed on the card receiving the computing means 9.
[0042] This device thus permits in operation, the control of the
speed of the turbine 2a and the control of the expiration valve
through the electro-valve to provide several modes of operation and
particularly modes of volumetric operation. Thus several modes of
operation are sought and particularly modes of operation with
inspiration and expiration pressure standards or modes for which a
volume of air called a target volume is predetermined, or mixed
modes.
[0043] The operation of the apparatus is based on a system of
self-adaptive control in a closed loop, of the speed of the flow
generator. With this flow generator is associated a controlled
expiration device, without a member for regulation of the
supplemental principal flow.
[0044] In particular, the detection of an increasing slope of
pressure can be translated by a level of acceleration of the
turbine 2a and the detection of the transition between the
inspiration phase and the expiration phase can be translated by a
deceleration of the turbine 2a.
[0045] This control is effected by inspiration pressure or flow
rate signals and according to control laws, based on proportional
and integral coefficients, which differ according to the modes of
ventilation, the adjustments of the pressure or flow rate and in
particular the phases of the respiratory cycle.
[0046] The operation of the device and the associated ventilation
process will be explained for example in the case of a mode in
which an inspiration pressure Pi, an expiration pressure Pe as well
as a form of obtaining the inspiration pressure based on the time
of pressure increase, are fixed. The time of insufflation is here
dependent on a level of triggering the expiration adjusted on the
basis of the measurement of a drop in flow rate measured in the
inspiration detector 7, after obtaining a maximum insufflation flow
rate available for the patient.
[0047] A limiting parameter for the time of insufflation is the
minimum threshold corresponding to the slope of pressure measured;
another parameter is a maximum threshold of safety for the
insufflation time which corresponds to the last inspiration time
carried out or at most to three seconds. Other safety parameters
can be taken into account such as a safety frequency.
[0048] According to this embodiment, the objective of the
insufflation phase is the establishment of a pressure level Pi with
a variable time of increase and a holding time depending on the
behavior of the associated flow rate.
[0049] The objective of the expiration phase is to maintain a
pressure level Pe up to the beginning of the following inspiration
phase, but also sufficiently to rinse the circuit so as to evacuate
the residual expired gases.
[0050] To carry out inspiration cycles, the phases of pressure
increase with increased slopes of pressure are carried out by an
acceleration of the turbine 2a. The pressure is controlled in the
inspiration pressure sensor 6.
[0051] During the insufflation phase corresponding to the
inspiration phase, the computation means control the expiration
valve 14, which is part of the third circuit 11 connected to the
mask 4 or to the intubation device, via the proportional
electro-valve 15 and the second circuit 16, according to
pressure.
[0052] The transition between an inspiration phase and an
expiration phase is effected itself by a controlled deceleration of
the turbine 2a and the expiration valve 14, which is part of the
third circuit 11 connected to the mask 4 or to the intubation
device, is controlled, through the proportional electro-valve 15
and the second circuit 16, with a pressure regulation member of the
first circuit 3.
[0053] During the expiration phase, the computation means and the
means for controlling the speed of rotation of the generator adapt
the speed of the turbine 2 as a function of an expiration pressure
threshold beyond a loss regulated by the expiration valve 14 so as
to create the rinsing flow rate of the first circuit.
[0054] The non-return clapet system 12 and the spontaneous
respiration clapet 13 permit balancing the rinsing pressure which
is maintained sufficiently low to limit the phenomenon of
expiration braking without being canceled to avoid all heating of
the turbine 2a.
[0055] In the case of ventilation for which a current volume as
well as a frequency and a cycling ratio are fixed, the objective of
the insufflation phase is the distribution of a current volume Vt
with a suitable flow rate shape and during a time fixed by the
frequency levels and the ratio of cycling regulated by the
interface 25.
[0056] In this case, during insufflation, the patient current
comprising the circuit 3, the mask 4 or intubation device is
maintained sealed, against parasitic loss by the closing of the
valve 14 controlled by the electro-valve 15. As a result, there is
an increase in pressure of the circuit 3 and of the pulmonary
system of the patient depending on the characteristics of the
patient. In the case of exceeding the objective of maximum pressure
measured with the pressure sensor 6, it is possible to cause the
pressure in the control circuit 16 of the valve 14 by a command of
the electro-valve 15 and to pass immediately into the expiration
phase.
[0057] In the case of a target volume mode, the operator enters by
the interface means a target volume standard into the computation
means 9 which, as a function of this parameter and other parameters
entered by the interface such as the frequency of minimum cycle
and/or safety, cycling ratio, high pressure threshold, will
permanently adjust the insufflation pressure between a low pressure
threshold and a maximum pressure threshold so as to maintain the
current volume inhaled by the patient as nearly as possible to a
predefined target volume, namely for example between target volume
Vt and target volume Vt+20%.
[0058] According to the target volume mode, it is particularly
necessary to be able at the same time to adjust precisely the
pressure by pressure steps between the cycles. For example, for a
pressure standard of the order of 20 millibars, the steps between
cycles are defined between 0.5 millibar and 2 millibars so as to
react immediately to the detection of an unbalance without having a
strong reaction that would be uncomfortable to the patient.
[0059] This pressure adjustment is made according to the invention
without a regulator device such as the generator but by controlling
the speed of the turbine 2a of the generator 2 as a function of the
pressure measurements of the sensor 6 of the pressure of the
patient and by causing to operate the expiration circuit comprising
the expiration valve 14 following through the proportional
electro-valve 15 in which, in this configuration, the flow
generator is connected to the second circuit, the non-return flap
12 of the first circuit 3 permitting preserving a pressure slightly
greater in the second circuit relative to the first circuit.
[0060] Thus the device permits providing a respiratory gas
according to respiratory cycles comprising phases of inspiration
and expiration, the measuring means 5, 6, 7, 8 and the computation
means 9 acting on the speed control means 10 so as automatically to
control the speed of rotation of the turbine 2 as a function of the
pressure and/or volume standards, of the detection of inspiration
and expiration phases, of patient pressure signals and/or
inspiration flow rate signals.
[0061] With the device of the invention, the expiration valve 14 is
controlled by the pressure during the inspiration phase and by a
regulating member during the expiration phase.
[0062] The device according to the invention thus permits
ventilating a patient by pressure or volume with a patient circuit
provided with an expiration device controlled by a simple control
of the speed of the turbine.
* * * * *