Method and system for analyzing a patients respiratory activity and corresponding uses

• US 9,649,051 B2
• Filed: 04/28/2011
• Issued: 05/16/2017
• Est. Priority Date: 04/30/2010
• Status: Active Grant

• Current Assignee: Centre National De La Recherche Scientifique
• Original Assignee: Centre National De La Recherche Scientifique
• Inventors: Hanusse, Patrick
• Primary Examiner(s): Mallari, Patricia
• Assistant Examiner(s): TOTH, KAREN E
• Application Number:
  US13/695,266
• Publication Number:
  US 20130096452A1
• Time in Patent Office: 2,210 Days
• CPC Class Codes: A61B 5/087 Measuring breath flow
• CPC Class Codes: A61B 5/72 Signal processing specially adapted for physiological signals or for diagnostic purposes character recognition, recognising digital ink, document-oriented image-based pattern recognition G06V30/00; recognition or understanding of postal images G06V30/424
• CPC Class Codes: A61B 5/7225 Details of analog processing, e.g. isolation amplifier, gain or sensitivity adjustment, filtering, baseline or drift compensation A61B5/30, A61B5/316 take precedence; transformers for specific applications H01F38/00; amplifiers H03F
• CPC Class Codes: A61B 5/7271 Specific aspects of physiological measurement analysis A61B5/316, A61B5/349 and A61B5/374 take precedence
• CPC Class Codes: A61B 5/7275 Determining trends in physiological measurement data; Predicting development of a medical condition based on physiological measurements, e.g. determining a risk factor
• CPC Class Codes: A61B 5/7278 Artificial waveform generation or derivation, e.g. synthesising signals from measured signals A61B5/327 takes precedence
• CPC Class Codes: A61M 16/024 including calculation means, e.g. using a processor
• CPC Class Codes: A61M 16/06 Respiratory or anaesthetic masks
• CPC Class Codes: G06F 17/141 Discrete Fourier transforms

Abstract

A method for analyzing the respiratory activity of a patient includes steps for acquiring at least one respiratory activity signal including at least one elementary signal corresponding to a respiratory cycle, the general form of which may be expressed by x(t)=x₀+x₁ cos(Φ(t)), wherein Φ(t) is the phase of the elementary signal, and for analyzing the respiratory activity signal. The analysis includes steps for extracting, from the respiratory activity signal, the elementary signal, for determining an expression of a phase equation

$F\left(\Phi \right)=\frac{d\Phi }{dt}$
of the elementary signal and for determining an expression of the phase Φ(t) of the elementary signal as a function of parameters measuring the anharmonicity of the elementary signal and its morphology, from p cos_n and p sin_n functions defined by:

$p{\cos }_n\left(t,r\right)=\sum _{k=1}^{\infty }\cos \left(\mathrm{kt}\right)\frac{r^k}{k^n}\mathrm{and}p{\sin }_n\left(t,r\right)=\sum _{k=1}^{\infty }\sin \left(\mathrm{kt}\right)r\frac{r^k}{k^n}.$

Claims

1. A method of assisting the respiratory activity of a patient, comprising:

placing a respiratory mask over the mouth and nose of the patient, wherein the respiratory mask comprises a pneumotachograph configured to measure flow rates of inhaled and exhaled air by the patient and to generate from the flow rates at least one respiratory activity signal comprising at least one elementary signal corresponding to a respiratory cycle, the general form of which may be expressed by x(t)=x₀+x₁ cos(Φ

(t)), wherein t is time, Φ

(t) is the phase of said elementary signal, x₀ and x₁ are coefficients;

determining respiratory activity of the patient by performing an analysis of said respiratory activity signal, wherein the analysis of said respiratory activity signal comprises the following steps;

extracting, from said respiratory activity signal, said elementary signal;

determining an expression of a phase equation

2. The method of assisting respiratory activity according to claim 1, wherein the phase equation is expressed as:

3. The method of assisting respiratory activity according to claim 2, wherein the elementary signal is expressed by two parameters r and Φ

₀, as;

x(t)=x₀+a₁h sin(t,r)+b₁h cos(t,r)

wherein a₁=x₁ cos(Φ

₀), b₁=−

x₁ sin(Φ

₀), and Φ

₀ is a phase origin, the h sin and h cos functions being defined by;

4. The method of assisting respiratory activity according to claim 1, wherein the phase equation is expressed as:

5. The method of assisting respiratory activity according to claim 4, wherein the expression of the phase Φ

(t) is determined as;