Ventilator method, ventilator and memory medium

• US 20050211249A1
• Filed: 05/19/2005
• Published: 09/29/2005
• Est. Priority Date: 11/19/2002
• Status: Abandoned Application

• Current Assignee: Mirko Wagner, Siegfried Haussler
• Original Assignee: Mirko Wagner, Siegfried Haussler
• Inventors: Haussler, Siegfried, Wagner, Mirko
• Application Number:
  US11/132,695
• Publication Number:
  US 20050211249A1
• Time in Patent Office: Days
• US Class Current: 128/204.230
• CPC Class Codes: A61M 16/0069 the speed thereof being controlled by respiratory parameters, e.g. by inhalation
• 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 2016/0036 in the breathing tube and used in both inspiratory and expiratory phase
• CPC Class Codes: A61M 2230/42 Rate

Abstract

The invention relates to a method for a ventilator, wherein a first polynomial is fitted to the time history of a respiratory flow. The invention moreover relates to a method for a ventilator, wherein the derivative of the respiratory flow with respect to time is estimated and a second polynomial is fitted to the derivative. The invention moreover relates to a ventilator, in particular to a CPAP-apparatus, for performing this method, as well as to a memory medium comprising corresponding programs.

Claims

1. A ventilator method comprising:

repeatedly measuring a respiratory air flow during the operation of the ventilator at several points in time;

storing the measured samples of the respiratory flow; and

fitting a first polynomial to the time history of the respiratory flow.

2. The method according to claim 1, wherein the first polynomial is a polynomial of the fourth order.

3. The method according to claim 1, wherein the measured points of the respiratory flow are subdivided in individual inspiration and expiration phases and the first polynomial is fitted to the points belonging to an inspiration phase.

4. The method according to claim 1, wherein the ventilator transmits the polynomial coefficients of the first polynomial via an interface to an external memory unit.

5. The method according to claim 1, wherein the ventilator transmits the polynomial coefficients of the first polynomial via a modem and a public telephone network (PSTN) to another computer.

6. The method according to claim 2 further comprising:

calculating the derivative of the first polynomial, thereby forming a second polynomial of the third order.

7. A ventilator method comprising:

repeatedly measuring the respiratory flow during the operation of the ventilator at several points in time;

storing the measured points of the respiratory flow;

estimating the derivative of the respiratory flow with respect to time; and

fitting a second polynomial of the third order to the derivative.

8. The method according to claim 7, further comprising:

determining the three zeros of the second polynomial;

evaluating the imaginary part of the two conjugate complex zeros if the second polynomial only has one real zero.

9. The method according to claim 8, wherein further the area of the triangle formed by the three zeros in the complex plane is calculated.

10. A ventilator comprising:

a flow sensor for repeatedly measuring a respiratory air flow during the operation of the ventilator at several points in time;

a command memory; and

a central processing unit for processing commands stored in the command memory, so that the measured samples of the respiratory flow are stored; and

the central processing unit fits a first polynomial to the time history of the respiratory flow.

11. The ventilator of claim 10, wherein the ventilator is a CPAP-apparatus.

12. The ventilator according to claim 10, wherein the first polynomial is a polynomial of the fourth order.

13. The ventilator according to claim 10, wherein the command memory comprises commands instructing the central processing unit to subdivide the measured samples of the respiratory flow in individual inspiration and expiration phases and the first polynomial is fitted to the points belonging to an inspiration phase.

14. The ventilator according to claim 10, wherein the ventilator further comprises an interface for transmitting the polynomial coefficients of the first polynomial to an external memory unit.

15. The method according to claim 10, wherein the ventilator transmits the polynomial coefficients of the first polynomial via a modem and a public telephone network (PSTN) to another computer.

16. A ventilator, comprising:

a flow sensor for repeatedly measuring a respiratory air flow during the operation of the ventilator at several points in time;

a command memory; and

a central processing unit for processing commands stored in the command memory, so that the measured samples of the respiratory flow are stored, the derivative of the respiratory flow with respect to time is estimated, and a second polynomial of the third order is fitted to the derivative.

17. The ventilator according to claim 16, the command memory further comprising commands instructing the central processing unit to determine the three zeros of the second polynomial and evaluate the imaginary part of the two conjugate complex zeros if the second polynomial only has one real zero.

18. The method according to claim 17, the command memory further comprising commands instructing the central processing unit to calculate the area of the triangle formed by the three zeros in the complex plane.

19. A memory medium for use with a ventilator, comprising data constituting coefficients of polynomials fitted to data obtained from respiratory flow data provided by the ventilator.

20. A memory medium for use with a ventilator, the memory medium comprising data constituting commands to be processed by a central processing unit of the ventilator, the ventilator comprising a flow sensor for repeatedly measuring a respiratory air flow during the operation of the ventilator at several points in time;

the commands instructing the central processing unit to store the measured samples of the respiratory flow and to fit a first polynomial to the time history of the respiratory flow.