Breathing assistance apparatus

• US 20060272642A1
• Filed: 03/24/2004
• Published: 12/07/2006
• Est. Priority Date: 03/24/2003
• Status: Active Grant

• Current Assignee: Resmed Paris (ResMed Incorporated)
• Original Assignee: Societe D'applications Industrielles Medicales Et Electroniques
• Inventors: Chalvignac, Philippe
• Granted Patent: US 7,905,231 B2
• Time in Patent Office: Days
• US Class Current: 128/204.230
• CPC Class Codes: A61M 16/0057 Pumps therefor
• CPC Class Codes: A61M 16/0066 Blowers or centrifugal pumps
• CPC Class Codes: A61M 16/0069 the speed thereof being controlled by respiratory parameters, e.g. by inhalation
• CPC Class Codes: A61M 16/024 including calculation means, e.g. using a processor
• CPC Class Codes: A61M 16/20 Valves specially adapted to medical respiratory devices
• CPC Class Codes: A61M 16/203 Proportional
• CPC Class Codes: A61M 16/206 Capsule valves, e.g. mushroom, membrane valves
• CPC Class Codes: A61M 2016/0021 with a proportional output signal, e.g. from a thermistor
• CPC Class Codes: A61M 2016/0039 in the inspiratory circuit
• CPC Class Codes: A61M 2016/0042 in the expiratory circuit
• CPC Class Codes: A62B 9/006 Indicators or warning devices, e.g. of low pressure, contamination

Abstract

This invention concerns a breathing assistance apparatus capable of operating in alternating inhalation and expiratory phases wherein; a) the control means of the apparatus comprise selection means (152) capable of selecting a pressure parameter or a flow rate parameter to define; b) the said reference value for the gas source, the said selection means are controlled by an automatic control unit (51), the said control unit being: I) connected to pressure and flow rate sensors situated on the inhalation duct to form a direct closed regulation loop for selecting a reference value parameter, II) associated to a programme allowing the selection to be made in real time from a pressure or flow rate signal, so that the association of a direct closed regulation circuit for the selection of a reference value parameter with a valve permitting proportional operation, allows real time control of barometric and volumetric operating modes of the apparatus, between the inhalation and expiratory phases and during these phases. The invention also concerns associated operating processes.

Claims

1. A breathing assistance apparatus capable of operating in alternating inhalation and expiratory phases, the apparatus comprising:

a pressurized respiratory gas source,

control means capable of transmitting a reference value of a gas related parameter to the pressurized respiratory gas source, the control means including selection means capable of selecting a pressure parameter or a flow rate parameter to define the reference value of the gas related parameter,

an inhalation duct to supply gas from the pressurized respiratory gas source to a patient,

an expiratory duct for expiratory gas of the patient,

an inhalation valve disposed on the inhalation duct, the inhalation valve comprising means to allow the gas from the gas source to pass to make possible proportional operation, the inhalation valve being controlled by means which are distinct from the pressurized respiratory gas source,

an expiratory valve on the expiratory gas source to help establish a positive expiratory pressure,

a pressure sensor and a flow rate sensor associated with the inhalation duct, and

an automatic control unit for controlling the selection means, the automatic control unit being

connected to the pressure and flow rate sensors to form a direct closed regulation circuit for selecting a reference value parameter, and

associated to a programme allowing a selection to be made in real time from a pressure signal or flow rate signal,

so that association of a direct closed regulation loop for the selection of a particular reference value parameter with the inhalation or expiratory valve permitting proportional operation allows real time control of barometric and volumetric operating modes of the breathing assistance apparatus, between or during the inhalation and expiratory phases.

2. Apparatus according to claim 1, wherein during the expiratory phases of the apparatus, the inhalation valve is operable to generate a leak rate to compensate leaks so that no leak connection is associated with the inhalation valve.

3. Apparatus according to claim 1 or claim 2, wherein the pressurized respiratory gas source comprises a centrifugal fan type turbine with an axial air intake and peripheral output and with an inertia value less than around 150 gcm².

4. Apparatus according to claim 1, further comprising:

a second flow rate sensor associated with the expiratory duct, and

comparison means, wherein the flow rate sensors associated with the inhalation and expiratory ducts are connected to the comparison means to compare respective flow rates in the inhalation and expiratory ducts.

5. Apparatus according to claim 4, further comprising processing means operable to filter a difference between the respective flow rates in real time, the processing means being associated with the comparison means.

6. Apparatus according to claim 5, wherein the processing means is connected to the automatic control unit, to a memory, and to a processor programmed to trigger a new inhalation phase when the filtered difference is higher than a pre-determined threshold.

7. Apparatus according to claim 1, wherein the inhalation valve comprises:

a valve body comprising an orifice connected to the inhalation duct, and,

a moving element operable to block the orifice in a closed position, and to at least partially free the orifice in an open position, the moving element including a recess for aligning with the orifice to allow the gas from the gas source to pass through to the inhalation duct, the said recess comprising;

a first part having a geometry corresponding to a proportional operation of the inhalation valve when the first part is aligned with the orifice, and

a second part having a geometry corresponding to all or nothing operation of the inhalation valve when the second part is aligned with the orifice.

8. Apparatus according to claim 7, wherein the recess is shaped so that when the moving element moves the inhalation valve from the closed position to the open position, the first part is aligned with the recess and then the second part is aligned with the said recess if movement continues.

9. Apparatus according to claim 8, wherein:

the first part of the recess is generally triangular,

the second part of the recess is generally rectangular, and

a base of the triangle of the first part of the recess is parallel with one side of the rectangle of the second part of the recess.

10. Apparatus according claim 1, further comprising a micro-turbine operable to control the expiratory valve so that the positive expiratory pressure is controlled.

11. Apparatus according to claim 10, wherein the micro-turbine is directly connected to the expiratory valve and no intermediate element is positioned between the micro-turbine and the expiratory valve.

12. An operating control process for controlling a breathing assistance apparatus comprising a pressurized respiratory gas source;

control means capable of transmitting a reference value of a gas related parameter to the pressurized respiratory gas source, the control means including selection means capable of selecting a pressure parameter or a flow rate parameter to define the reference value of the gas related parameter;

an inhalation duct to supply gas from the pressurized respiratory gas source to a patient;

an expiratory duct for expiratory gas of the patient;

an inhalation valve disposed on the inhalation duct, the inhalation valve comprising means to allow the gas from the gas source to pass to make possible proportional operation, the inhalation valve being controlled by means which are distinct from the pressurized respiratory gas source;

an expiratory valve on the expiratory gas source to help establish a positive expiratory pressure;

a pressure sensor and a flow rate sensor associated with the inhalation duct; and

an automatic control unit for controlling the selection means, the process comprising;

operating a micro-turbine; and

closing the expiratory valve based on the micro-turbine to regulate a positive expiratory pressure during the expiratory phases.

13. Process according to claim 12, wherein the micro-turbine operates constantly and the expiratory valve is controlled by selective connection of a pneumatic control line of the expiratory valve with the micro-turbine.

14. A process for operating a breathing assistance apparatus in a volumetric mode, the breathing assistance apparatus comprising a pressurized respiratory gas source;

control means capable of transmitting a reference value of a gas related parameter to the pressurized respiratory gas source, the control means including selection means capable of selecting a pressure parameter or a flow rate parameter to define the reference value of the gas related parameter;

an inhalation duct to supply gas from the pressurized respiratory gas source to a patient;

an expiratory duct for expiratory gas of the patient;

an inhalation valve disposed on the inhalation duct, the inhalation valve comprising means to allow the gas from the gas source to pass to make possible proportional operation, the inhalation valve being controlled by means which are distinct from the pressurized respiratory gas source;

an expiratory valve on the expiratory gas source to help establish a positive expiratory pressure;

a pressure sensor and a flow rate sensor associated with the inhalation duct; and

an automatic control unit for controlling the selection means, the process comprising;

selecting the volumetric mode; and

controlling the gas source on the basis of a measured pressure parameter on the inhalation duct;

wherein control of volume of the gas delivered to a patient is obtained by the control of the gas source.

15. Process according to claim 14, wherein no pressure difference between upstream and downstream parts of the inhalation valve is used.

16. Process according to claim 14, wherein control of the gas source is obtained through control of the rotation speed of a rotor of the gas source.