Ventilator leak compensation

• US 8,434,480 B2
• Filed: 03/30/2009
• Issued: 05/07/2013
• Est. Priority Date: 03/31/2008
• Status: Active Grant

• Current Assignee: Covidien LP (Medtronic Plc)
• Original Assignee: Covidien LP (Medtronic Plc)
• Inventors: Jafari, Mehdi M., Jimenez, Rhomere S., McCoy, Edward R., Aviano, Jeffrey K.
• Primary Examiner(s): Thanh, Loan
• Assistant Examiner(s): DITMER, KATHRYN ELIZABETH
• Application Number:
  US12/414,419
• Publication Number:
  US 20090241962A1
• Time in Patent Office: 1,499 Days
• Field of Search: 128/204.18, 128/204.21, 128/205.13, 128/205.14
• US Class Current: 128/204.21
• CPC Class Codes: A61M 16/0057 Pumps therefor
• 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 16/04 Tracheal tubes catheters in general A61M25/00
• CPC Class Codes: A61M 16/06 Respiratory or anaesthetic masks
• CPC Class Codes: A61M 16/0666 Nasal cannulas or tubing devices for improving normal breathing through the nose A61F5/08; nose filters A62B23/06; outside holding devices A61M25/02
• CPC Class Codes: A61M 16/0875 Connecting tubes
• CPC Class Codes: A61M 2016/0021 with a proportional output signal, e.g. from a thermistor
• CPC Class Codes: A61M 2016/0027 pressure meter
• CPC Class Codes: A61M 2016/0033 electrical
• CPC Class Codes: A61M 2205/15 Detection of leaks
• CPC Class Codes: A61M 2205/502 User interfaces, e.g. screens or keyboards
• CPC Class Codes: A61M 2205/52 with memories providing a history of measured variating parameters of apparatus or patient
• CPC Class Codes: A61M 2230/46 Resistance or compliance of the lungs

Abstract

A ventilator including a pneumatic system for providing and receiving breathing gas, and a controller operatively coupled with the pneumatic system. The controller is operable to control circulation by the pneumatic system of breathing gas to and from a patient, and to adjust at least one of a volume and pressure of breathing gas delivered to the patient, such adjustment being based upon elastic properties of a component used to fluidly couple the pneumatic system to a patient.

Claims

1. A ventilator, comprising:

a pneumatic system for providing and receiving breathing gas;

a component for fluidly coupling the pneumatic system to a patient, wherein the component comprises a leak-susceptible orifice that varies in size during operation of the ventilator, wherein the varying size of the leak-susceptible orifice is directly related to an applied pressure; and

a controller operatively coupled with the pneumatic system, where the controller is configured to perform the following steps;

control circulation by the pneumatic system of breathing gas to and from a patient, and

adjust at least one of a volume and pressure of breathing gas delivered to the patient to account for leakage from the pneumatic system, such adjustment taking into account the varying size of the leak-susceptible orifice.

2. The ventilator of claim 1, where the component is a physical patient interface.

3. The ventilator of claim 2, where the physical patient interface is a facial breathing mask.

4. The ventilator of claim 3, where the adjustment is based upon elastic and rigid leak properties of the facial breathing mask.

5. The ventilator of claim 1, where the adjustment is based upon an elastic modulus of a material comprising the component.

6. The ventilator of claim 1, further comprising an operator interface configured to accept operator input, the adjustment being dependent at least in part upon such operator input.

7. The ventilator of claim 6, where the controller is configured to establish elastic properties of the component based upon the operator input at the operator interface.

8. A ventilator, comprising:

a pneumatic system for providing and receiving breathing gas;

an airway including a physical patient interface and a breathing circuit for fluidly coupling the pneumatic system with a patient, wherein the airway comprises a leak-susceptible orifice that varies in size during operation of the ventilator, wherein the varying size of the leak-susceptible orifice is directly related to an applied pressure; and

a controller operatively coupled with the pneumatic system, where the controller is configured to perform the following steps;

control delivery of breathing gas from the pneumatic system to the patient;

derive the varying size of the leak-susceptible orifice based on an elastic modulus of the airway and the applied pressure; and

adjust such delivery for airway leakage by taking into account the varying size of the leak-susceptible orifice.

9. The ventilator of claim 8, where the controller is configured to dynamically update a magnitude of the adjustment for airway leakage during operation of the ventilator.

10. The ventilator of claim 9, where the controller is configured to dynamically update the magnitude of the adjustment during each of a plurality of breathing cycles.

11. The ventilator of claim 8, where the physical patient interface comprises a facial breathing mask which at least partly defines the leak-susceptible orifice.

12. In a ventilator having a pneumatic system and an airway adapted to fluidly couple the pneumatic system to a patient, a leak compensation method, comprising:

providing a baseline level of leak compensation based upon a size of a leak-susceptible orifice in the airway;

establishing elastic properties of a component of the airway containing the leak-susceptible orifice, wherein the elastic properties of the component are derived based on material properties of the component;

adjusting the baseline level of leak compensation in response to a pressure sufficient to cause deformation of the leak-susceptible orifice, wherein the deformation of the leak-susceptible orifice is based upon the elastic properties of the component and is directly related to the pressure, and wherein a magnitude of the adjustment takes into account the elastic properties of the component.

13. The method of claim 12, where the component is a physical patient interface.

14. The method of claim 13, where the physical patient interface is a facial ventilator mask.

15. The method of claim 12, where the component is a breathing circuit fluidly coupled between the patient and the pneumatic system.

16. The method of claim 12, where adjusting the baseline level of leak compensation is performed during a plurality of patient breathing cycles.

17. The method of claim 16, where the magnitude of the adjustment is dynamically updated at least once per breathing cycle.

18. The method of claim 12, further comprising accepting operator input at an operator interface of the ventilator, and using such operator input in the establishing of the elastic properties of the component.

19. A ventilator, comprising:

a pneumatic system for providing and receiving breathing gas;

an airway including a physical patient interface and a breathing circuit for fluidly coupling the pneumatic system with a patient; and

a controller operatively coupled with the pneumatic system, where the controller is configured to perform the following steps;

control circulation by the pneumatic system of breathing gas to and from the patient, and

make dynamic adjustments in breathing gas flow to compensate for a leak in the airway, where such leak compensation takes into account rigid leak properties of a fixed-size orifice of the airway and elastic leak properties of a variable-size orifice of the airway, where the elastic leak properties of the variable-size orifice of the airway are directly related an applied pressure.