Systems and methods for ventilation in proportion to patient effort

• US 9,126,001 B2
• Filed: 06/21/2013
• Issued: 09/08/2015
• Est. Priority Date: 06/06/2008
• Status: Active Grant

• Current Assignee: Covidien LP (Medtronic Plc)
• Original Assignee: Covidien LP (Medtronic Plc)
• Inventors: Masic, Milenko, Guy, Jon
• Primary Examiner(s): MATTER, KRISTEN CLARETTE
• Application Number:
  US13/924,056
• Publication Number:
  US 20130284173A1
• Time in Patent Office: 809 Days
• Field of Search: 12820421-20423
• US Class Current: 1/1
• CPC Class Codes: A61B 5/08 Detecting, measuring or recording devices for evaluating the respiratory organs A61B5/0205 takes precedence
• CPC Class Codes: A61M 16/0003 Accessories therefor, e.g. sensors, vibrators, negative pressure
• CPC Class Codes: A61M 16/0051 with alarm devices
• CPC Class Codes: A61M 16/0057 Pumps therefor
• 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 16/12 by mixing different gases
• CPC Class Codes: A61M 2016/0015 inhalation detectors
• CPC Class Codes: A61M 2016/0018 electrical
• CPC Class Codes: A61M 2016/0027 pressure meter
• CPC Class Codes: A61M 2016/0036 in the breathing tube and used in both inspiratory and expiratory phase
• CPC Class Codes: A61M 2016/0039 in the inspiratory circuit
• CPC Class Codes: A61M 2016/0042 in the expiratory circuit
• CPC Class Codes: A61M 2205/3303 Using a biosensor
• CPC Class Codes: A61M 2205/50 with microprocessors or computers
• CPC Class Codes: G01F 1/00 Measuring the volume flow or mass flow of fluid or fluent solid material wherein the fluid passes through a meter in a continuous flow measuring a proportion of the volume flow G01F5/00
• CPC Class Codes: G01F 1/34 by measuring pressure or differential pressure

Abstract

Various embodiments of the present disclosure provide systems, methods and devices for respiratory support. As one example, a ventilation system is disclosed that includes a computer readable medium including instructions executable by a processor to receive a measured pressure value and a net flow value. A patient effort value is calculated based on a relationship between patient effort, the measured pressure value and the net flow value. The instructions are further executable to calculate a gas delivery metric that varies as a function of the patient effort value. Gas is then caused to be delivered consistent with the gas delivery metric.

Claims

1. A method for respiratory support, the method comprising:

identifying a target proportion of patient effort;

measuring a pressure and providing a measured pressure;

measuring an inlet flow and an outlet flow, and providing a measured net flow;

using a relationship between a first value related to the measured pressure, a second value related to the measured net flow and an estimated normalized prediction error, wherein the estimated normalized prediction error is based at least in part on a current estimated value of a parameter vector to calculate an estimate of patient effort from the measured pressure and measured net flow; and

supplying a gas in proportion to the estimate of patient effort based on the target proportion.

2. The method of claim 1, wherein supplying the gas in proportion to the estimate of patient effort includes supplying the gas at a pressure in proportion to the estimate of patient effort.

3. The method of claim 1, wherein supplying the gas in proportion to the estimate of patient effort includes supplying the gas at a flow in proportion to the estimate of patient effort.

4. The method of claim 1, wherein the estimate of patient effort is further based on a combination of one or more intermediate values derived from the measured pressure and measured net flow, the one or more intermediate values selected from:

a filtered pressure value and a regression vector.

5. The method of claim 1, wherein the second value is selected from:

a filtered version of the measured net flow, and the measured net flow.

6. The method of claim 1, wherein the first value is selected from:

a filtered version of the measured pressure, and the measured pressure.

7. The method of claim 1, wherein the relationship is a parameterized system input to output relationship.

8. The method of claim 7, wherein the parameterized system input to output relationship is the regression form:

z=Θ

^Tφ

+φ

_d, wherein z is a filtered pressure value, Θ

is a current estimated value of a parameter vector, φ

is at least a part of regression vector, and φ

_d is a filtered patient effort.

9. The method of claim 8, wherein the parameterized system input to output relationship is derived from a transfer function.

10. The method of claim 9, wherein the transfer function is derived from the model:

11. A ventilation system, the system comprising:

a gas inlet;

a gas outlet;

a tube coupling the gas inlet and the gas outlet;

a pressure sensor, wherein the pressure sensor is operable to provide a measured pressure value indicating a pressure in the tube;

a first flow sensor, wherein the first flow sensor is operable to provide an inlet flow value indicating a flow associated with the gas inlet;

a second flow sensor, wherein the second flow sensor is operable to provide an outlet flow value indicating a flow associated with the gas outlet; and

a processor communicably coupled to a computer readable medium, wherein the computer readable medium includes instructions executable by the processor to;

identifying a target proportion of patient effort;

receive a measured pressure value;

receive a net flow value;

calculate a patient effort value based on a relationship between patient effort, the measured pressure value, the net flow value, and an estimated normalized prediction error, wherein the estimated normalized prediction error is based at least in part on a current estimated value of a parameter vector;

calculate a gas delivery metric that varies as a proportion of the patient effort value, wherein the proportion is the target proportion;

determine an inhalation phase based on the patient effort value; and

cause a gas to be delivered consistent with the gas delivery metric.

12. The system of claim 11, wherein the computer readable medium includes further instructions executable by the processor to:

identify a volume of gas to deliver to the patient through the patient circuit based on the target proportion of the patient effort.

13. The system of claim 12, wherein the computer readable medium includes further instructions executable by the processor to:

adjust flow of gas in the patient circuit based on the identified volume.

14. The system of claim 11, wherein the computer readable medium includes further instructions executable by the processor to:

deliver a flow of respiratory gas to the patient through the patient circuit based on the target proportion of the patient effort.

15. The system of claim 14, wherein the computer readable medium includes further instructions executable by the processor to:

adjusting a volume of gas in the patient circuit based on the identified volume.

16. A ventilation system, the ventilation system comprising:

a processor communicably coupled to a computer readable medium, wherein the computer readable medium includes instructions executable by the processor to;

receive a measured pressure value;

receive a net flow value;

calculate a patient effort value based on a relationship between patient effort, the measured pressure value, the net flow value, and an estimated normalized prediction error, wherein the estimated normalized prediction error is based at least in part on a current estimated value of a parameter vector;

calculate a volume of gas to be delivered based on a target proportion of the patient effort; and

cause a gas to be delivered consistent with the calculated volume of gas.

17. The system of claim 16 wherein the processor causes a gas to be delivered by adjusting a pressure in a patient circuit of the ventilation system.

18. The system of claim 16 wherein the processor causes a gas to be delivered by adjusting a flow of gas in a patient circuit of the ventilation system.