METHODS AND SYSTEMS FOR COMPENSATION OF TUBING RELATED LOSS EFFECTS

• US 20130255682A1
• Filed: 03/30/2012
• Published: 10/03/2013
• Est. Priority Date: 03/30/2012
• Status: Active Grant

• Current Assignee: Covidien LP (Medtronic Plc)
• Original Assignee: Nellcor Puritan Bennett LLC (Medtronic Plc)
• Inventors: Jafari, Mehdi M., Jimenez, Rhomere S., Aviano, Jeffrey K.
• Granted Patent: US 9,327,089 B2
• Time in Patent Office: Days
• US Class Current: 128/204.21
• CPC Class Codes: A61M 16/0051 with alarm devices
• CPC Class Codes: A61M 16/0063 Compressors
• 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 16/0833 T- or Y-type connectors, e.g. Y-piece
• CPC Class Codes: A61M 2016/0027 pressure meter
• CPC Class Codes: A61M 2016/0033 electrical
• CPC Class Codes: A61M 2205/702 automatically during use
• CPC Class Codes: A61M 2230/46 Resistance or compliance of the lungs

Abstract

A method for ventilating a patient with a ventilator includes consecutively delivering a plurality of substantially equal volume amounts into a closed ventilator circuit during a ventilator self-test, receiving a pressure measurement for each volume delivery, calculating a change in pressure for each volume delivery, consecutively releasing a plurality of substantially equal volume amounts from the closed ventilator circuit during the ventilator self-test, calculating a change in pressure for each volume release, fitting the calculated change in pressure data for volume delivery and volume release to an inhalation non-linear model equation and an exhalation non-linear model equation, respectively, deriving one or more inhalation tubing compliance compensation coefficients from the inhalation non-linear model equation, and deriving one or more exhalation tubing compliance compensation coefficients from the exhalation non-linear model equation.

Claims

1. A method for ventilating a patient with a ventilator, comprising:

consecutively delivering a plurality of substantially equal volume amounts into a closed ventilator circuit during a ventilator self-test;

receiving a pressure measurement for each volume delivery;

calculating a change in pressure for each volume delivery;

consecutively releasing a plurality of substantially equal volume amounts from the closed ventilator circuit during the ventilator self-test;

calculating a change in pressure for each volume release;

fitting the calculated change in pressure data for volume delivery and volume release to an inhalation non-linear model equation and an exhalation non-linear model equation, respectively;

deriving one or more inhalation tubing compliance compensation coefficients from the inhalation non-linear model equation; and

deriving one or more exhalation tubing compliance compensation coefficients from the exhalation non-linear model equation.

2. The method of claim 1, further including:

estimating an inhalation tubing compliance compensation volume by inputting the one or more inhalation tubing compliance compensation coefficients into a loss effect adjusted tubing compliance model.

3. The method of claim 2, further including:

adding the estimated inhalation tubing compliance volume to a desired tidal volume and delivering the combined volume amount to a patient through the circuit.

4. The method of claim 2, further including:

estimating an inhaled tidal volume amount of a patient by subtracting the inhalation tubing compliance volume amount for volume contraction in the tubing from a total delivered volume amount.

5. The method of claim 1, further including:

estimating an exhalation tubing compliance compensation volume by inputting the one or more exhalation tubing compliance compensation coefficients into a loss effect adjusted tubing compliance model.

6. The method of claim 5, further including:

estimating an exhaled tidal volume amount of a patient by subtracting the exhalation tubing compliance volume amount for volume expansion from a total expiratory volume amount.

7. The method of claim 1, further including:

estimating a circuit resistance by estimating at least one circuit resistance parameter from an equation utilizing the one or more tubing compliance compensation coefficients and utilizing the estimated circuit resistance parameter in an equation for estimating circuit resistance.

8. The method of claim 1, further including:

estimating a patient lung compliance by estimating at least one patient lung compliance parameter from an equation utilizing the one or more tubing compliance compensation coefficients and utilizing the estimated patient lung compliance parameter in an equation for estimating patient lung compliance.

9. A ventilator system comprising:

a pressure generating system adapted to generate a volume of breathing gas;

a ventilation tubing system including a patient interface for connecting the pressure generating system to a patient;

at least one sensor operatively coupled to at least one of the pressure generating system and the ventilation tubing system;

a loss effect compensation module, the loss effect compensation module configured to provide at least one instruction to consecutively deliver a plurality of substantially equal volume amounts into a closed ventilator circuit during a ventilator self-test, receive a pressure measurement for each volume delivery, calculate a change in pressure for each volume delivery, consecutively release a plurality of substantially equal volume amounts from the closed ventilator circuit during the ventilator self-test, calculate a change in pressure for each volume release, fit the calculated change in pressure data for volume delivery and volume release to an inhalation non-linear tubing compliance model equation and an exhalation non-linear tubing compliance model equation, respectively, derive one or more inhalation tubing compliance compensation coefficients from the inhalation non-linear model equation, and derive one or more exhalation tubing compliance compensation coefficients from the exhalation non-linear model equation; and

a processor in communication with the pressure generating system, the at least one sensor, and the loss effect compensation module and configured to receive the at least one instruction to consecutively deliver a plurality of substantially equal volume amounts from the loss effect compensation module.

10. The ventilator system of claim 9, wherein the loss effect compensation module is further configured to estimate an inhalation tubing compliance compensation volume by inputting the one or more inhalation tubing compliance compensation coefficients into a loss effect adjusted tubing compliance model.

11. The ventilator system of claim 10, wherein the loss effect compensation module is further configured to add the estimated inhalation tubing compliance volume amount to an inspiratory tidal volume amount and provide an instruction to deliver the combined amount to a patient through the tubing.

12. The ventilator system of claim 9, wherein the loss effect compensation module is further configured to estimate an exhalation tubing compliance compensation volume by inputting the one or more exhalation tubing compliance compensation coefficients into a loss effect adjusted tubing compliance model.

13. The ventilator system of claim 12, wherein the loss effect compensation module is further configured to estimate an expiratory tidal volume amount of a patient by subtracting the exhalation tubing compliance volume amount from a total expiratory volume amount.

14. The ventilator system of claim 9, wherein the loss effect compensation module is further configured to estimate a circuit resistance by estimating at least one circuit resistance parameter from an equation utilizing the one or more tubing compliance compensation coefficients and utilizing the estimated circuit resistance parameter in an equation for estimating circuit resistance.

15. The ventilator system of claim 9, wherein the loss effect compensation module is further configured to estimate a patient lung compliance by estimating at least one patient lung compliance parameter from an equation utilizing the one or more tubing compliance compensation coefficients and utilizing the estimated patient lung compliance parameter in an equation for estimating patient lung compliance.

16. The ventilator system of claim 9, wherein the loss effect compensation module is further configured to estimate a patient lung compliance by estimating at least one patient lung compliance parameter from an equation utilizing the tubing compliance compensation coefficients and utilizing the estimated patient lung compliance parameter in an equation for estimating patient lung compliance.

17. A computer-readable medium having computer-executable instructions for performing a method of ventilating a patient with a ventilator, the method comprising:

consecutively delivering a plurality of substantially equal volume amounts into a closed ventilator circuit during a ventilator self-test;

receiving a pressure measurement for each volume delivery;

calculating a change in pressure for each volume delivery;

consecutively releasing a plurality of substantially equal volume amounts from the closed ventilator circuit during the ventilator self-test;

calculating a change in pressure for each volume release;

fitting the calculated change in pressure data for volume delivery and volume release to an inhalation non-linear compliance model equation and an exhalation non-linear compliance model equation, respectively;

deriving one or more inhalation tubing compliance compensation coefficients from the inhalation non-linear model equation; and

deriving one or more exhalation tubing compliance compensation coefficients from the exhalation non-linear model equation.

18. The computer-readable medium of claim 17, further including:

estimating an inhalation tubing compliance compensation volume by inputting the one or more inhalation tubing compliance compensation coefficients into a loss effect adjusted tubing compliance model.

19. The computer-readable medium of claim 18, further including:

adding the estimated inhalation tubing compliance volume to a desired tidal volume and delivering the combined volume amount to a patient through the tubing.

20. The computer-readable medium of claim 17, further including:

estimating an exhalation tubing compliance compensation volume by inputting the one or more exhalation tubing compliance compensation coefficients into a loss effect adjusted tubing compliance model; and

estimating an exhaled tidal volume amount of a patient by subtracting the one or more exhalation tubing compliance volume amount for volume expansion from a total expiratory volume amount.