Process for the automatic recording of pressure-vs.-volume curves during artificial respiration

• US 20060037616A1
• Filed: 06/28/2005
• Published: 02/23/2006
• Est. Priority Date: 08/17/2004
• Status: Active Grant

• Current Assignee: Dragerwerk AG & Company KGaA (FPS Vermögensverwaltung GmbH)
• Original Assignee: Drager Medical AG & Co KG (Dragerwerk AG)
• Inventors: Lorenzen, Ralf, Seeger, Dieter, Kohl, Hans-Joachim
• Granted Patent: US 7,708,015 B2
• Time in Patent Office: Days
• US Class Current: 128/204.230
• CPC Class Codes: A61B 5/085 Measuring impedance of respiratory organs or lung elasticity
• CPC Class Codes: A61B 5/091 Measuring volume of inspired or expired gases, e.g. to determine lung capacity
• CPC Class Codes: A61M 16/00 Devices for influencing the respiratory system of patients by gas treatment, e.g. mouth-to-mouth respiration; Tracheal tubes stimulating the respiratory movement by mechanical, pneumatic or electrical means, iron lungs combined with gas breathing means A61H31/00
• CPC Class Codes: A61M 16/026 specially adapted for predicting, e.g. for determining an information representative of a flow limitation during a ventilation cycle by using a root square technique or a regression analysis
• CPC Class Codes: A61M 2016/0042 in the expiratory circuit

Abstract

A process, system and device are provided for automatically recording pressure-vs.-volume curves during artificial respiration with a respirator. The inspiration pressure is increased during the supply of a breathing gas volume flow under the control of a control unit. The resulting breathing gas volume flow rate is detected and the volume is determined from the latter by integration. The control unit compares the breathing gas volume flow detected during the phase of expiration with a preselected set point and acts on an expiration valve (12) in the expiration line (8) by means of a controller in case of deviation from the set point in order to return the breathing gas volume flow to the set point.

Claims

1. A process for the automatic recording of pressure-volume (PV) curves during artificial respiration with a respirator, the process comprising the steps of:

increasing inspiration pressure during the supply of a breathing gas volume flow under the control of a control unit;

detecting the resulting breathing gas volume flow;

determining the volume from the detected breathing gas volume flow by integration;

comparing, with the control unit, the breathing gas volume flow detected during the phase of expiration with a preselected set point;

acting on an expiration valve in an expiration line by means of a controller in case of deviation from the set point in order to return the breathing gas volume flow to the set point.

2. A process in accordance with claim 1, wherein a PI controller is used as the control function of the control unit.

3. A process in accordance with claim 1, wherein an essentially constant breathing gas volume flow is supplied during the phase of inspiration.

4. A process in accordance with claim 1, wherein measured pressure values are stored during the phase of inspiration and the pressure curve thus determined is used during the phase of expiration for anticipatory control for the controller.

5. A process in accordance with claim 1, wherein the PV curve is recorded by means of the control unit with the use of an expert system, which suggests the respiration parameters necessary for recording the PV curve, and especially data of preceding measurements or measured values of the current respiration are evaluated.

6. A process in accordance with claim 1, wherein the recording of the PV curve is started manually.

7. A process in accordance with claim 1, wherein the control unit automatically performs an evaluation of the PV curve after the recording of the PV curve in order to determine parameters of the curve, and the control unit subsequently automatically continues with breathing cycles, taking into account the determined parameters of the curves.

8. A device for the automatic recording of pressure-volume curves during artificial respiration with a respirator, the device comprising:

an inhalation line;

an exhalation line;

an expiration valve acting in the exhalation line;

a control unit with a controller;

a pressure settable breathing gas supply that can increase inspiration pressure during the supply of a breathing gas volume flow under the control of a control unit;

a breathing gas volume flow sensor for detecting the resulting breathing gas volume flow, said control unit determining the volume from the detected breathing gas volume flow by integration and comparing the breathing gas volume flow detected during the phase of expiration with a preselected set point and acting on said expiration valve in case of deviation from the set point in order to return the breathing gas volume flow to the set point.

9. A device in accordance with claim 8, wherein said expiration valve comprises a diaphragm valve and is pneumatically controlled by said control unit, said expiration valve being provided in said expiration line upstream of said breathing gas volume flow sensor for detecting the breathing gas volume flow.

10. A respirator system for automatic recording of a pressure-volume data during artificial respiration, the system comprising:

an inhalation line;

an exhalation line;

an expiration valve acting in the exhalation line;

a control unit;

a pressure settable breathing gas supply that can increase inspiration pressure during the supply of a breathing gas volume flow under the control of a control unit;

a breathing gas volume flow sensor for detecting the resulting breathing gas volume flow;

an integration means associated with said control unit for determining the volume from the detected breathing gas volume flow by integration;

a comparison means associated with said control unit for comparing the breathing gas volume flow detected during the phase of expiration with a preselected set point; and

a controller means associated with said control unit for acting on said expiration valve in case of deviation from the set point in order to return the breathing gas volume flow to the set point.

11. A respirator system in accordance with claim 10, wherein a PI controller is used to provide the control function of the control unit.

12. A respirator system in accordance with claim 10, wherein an essentially constant breathing gas volume flow is supplied during the phase of inspiration.

13. A respirator system in accordance with claim 10, wherein measured pressure values are stored during the phase of inspiration and a pressure curve thus determined is used during the phase of expiration for anticipatory control for the controller.

14. A respirator system in accordance with claim 10, wherein a PV curve is recorded by means of the control unit with the use of an expert system, which suggests the respiration parameters necessary for recording the PV curve, and data of preceding measurements or measured values of the current respiration are evaluated.

15. A respirator system in accordance with claim 10, wherein a recording of a PV curve is started manually.

16. A respirator system in accordance with claim 10, wherein the control unit automatically performs an evaluation of a PV curve after the recording of the PV curve in order to determine parameters of the curve, and it subsequently automatically continues with breathing cycles, taking into account the determined parameters of the curves.

17. A respirator system in accordance with claim 10, wherein said expiration valve comprises a diaphragm valve and is pneumatically controlled by said control unit, said expiration valve being provided in said expiration line upstream of said breathing gas volume flow sensor for detecting the breathing gas volume flow.