Methods and systems for determining dynamic hyperinflation

• US 20070049843A1
• Filed: 05/19/2006
• Published: 03/01/2007
• Est. Priority Date: 05/20/2005
• Status: Active Grant

• Current Assignee: Adidas AG
• Original Assignee: Adidas AG
• Inventors: Derchak, P.
• Granted Patent: US 7,878,979 B2
• Time in Patent Office: Days
• US Class Current: 600/538
• CPC Class Codes: A61B 5/0022 Monitoring a patient using a global network, e.g. telephone networks, internet
• CPC Class Codes: A61B 5/0205 Simultaneously evaluating both cardiovascular conditions and different types of body conditions, e.g. heart and respiratory condition
• CPC Class Codes: A61B 5/0806 by whole-body plethysmography measuring blood flow using plethysmography A61B5/0295; impedance plethysmography A61B5/053; measuring volume of the body or parts thereof A61B5/1073
• CPC Class Codes: A61B 5/0816 Measuring devices for examining respiratory frequency measuring frequency of electric signals G01R23/00
• CPC Class Codes: A61B 5/091 Measuring volume of inspired or expired gases, e.g. to determine lung capacity
• CPC Class Codes: A61B 5/1135 by monitoring thoracic expansion
• CPC Class Codes: A61B 5/318 Heart-related electrical modalities, e.g. electrocardiography [ECG]
• CPC Class Codes: A61B 5/411 Detecting or monitoring allergy or intolerance reactions to an allergenic agent or substance
• CPC Class Codes: A61B 5/6805 Vests
• CPC Class Codes: A61B 5/6831 Straps, bands or harnesses
• CPC Class Codes: G16H 40/67 for remote operation
• CPC Class Codes: G16Z 99/00 Subject matter not provided for in other main groups of this subclass

Abstract

This invention provides methods and systems for non-invasively determining the presence (and amount) or absence of dynamic hyperinflation in a subject. The invention is based on a novel combination of respiratory parameters that can be measured in a way that is non-invasive and unobtrusive to the subject. Dynamic hyperinflation is often a significant factor in the quality of life of patients suffering from a variety of obstructive pulmonary diseases, and this invention permits simple, routine tracking and management of dynamic hyperinflation in affected patients.

Claims

1. A computer-implemented method for assessing dynamic hyperinflation (DH) in a monitored subject comprising:

receiving respiratory data monitored during a current period of monitoring;

determining from the received data at one or more times during the monitoring period a parameter (M%RC) that reflects the relative contributions of expansions and contractions of the rib cage (RC) of the subject to tidal volumes (V_T) of the subject;

determining from the received data at one or more times during the monitoring period another parameter (MqdEELV) that reflects the accumulated changes in end-expiratory lung volume (MqdEELV); and

assessing DH in the subject during the monitoring period in dependence on both the determined MqdEELV parameters and the determined M%RC parameters.

2. The computer-implemented method of claim 1 wherein the monitoring period comprises a plurality of sub-periods, and wherein the M%RC parameter and the MqdEELV parameter are determined for each sub-period only from received respiratory data from that sub-period.

3. The computer-implemented method of claim 1 wherein DH is present during the monitoring period if the M%RC parameter values increase and if the MqdEELV parameter values decrease during the monitoring period.

4. The computer-implemented method of claim 1 wherein DH is present during a current monitoring period in comparison with a previous monitoring period if the M%RC parameter values during the current monitoring period are greater than during the previous monitoring period and if the MqdEELV parameter values during the current monitoring period are less than during the previous monitoring period.

5. The computer-implemented method of claim 4 wherein the previous monitoring period is a baseline period during which DH is known to be absent.

6. The computer-implemented method of claim 1 wherein determination of the M%RC parameter comprises dividing the respiratory volumes due to RC expansion and contraction by V_T.

7. The computer-implemented method of claim 6 wherein the received data comprises sizes at one or more selected positions on the RC of the subject, and wherein the respiratory volumes due to RC expansion and contraction are determined in dependence on one or more RC sizes.

8. The computer-implemented method of claim 1 wherein determination of the MqdEELV parameter comprises

determining a breath-by-breath change in expiratory lung volume (EELV);

determining a cumulative change in EELV in dependence on a plurality of consecutive breath-by-breath changes in EELV; and

determining the MqdEELV parameter in dependence on the absolute values of a plurality of cumulative changes in EELV.

9. The computer-implemented method of claim 8 wherein determination of a breath-by-breath change in EELV comprises subtracting the expiratory volume of the breath from the inspiratory volume of the breath.

10. The computer-implemented method of claim 1 wherein the received data comprises sizes at one or more positions on the torso of the subject, including one or more positions on the RC and one or more positions on the abdomen (AB), and wherein the method further comprises

determining a moment-by-moment lung volume parameter by linearly combining the RC sizes and the AB sizes;

and

determining V_T in dependence on a difference of the lung volume parameter at end of inspiration and the lung volume parameter at end of the following expiration.

11. The method of claim 1 wherein the subject comprises a mammal.

12. The method of claim 1 wherein the subject performs normal daily activities during the monitoring period.

25. A computer-readable medium comprising encoded instructions for causing a processor to perform the methods of claim 1.

13. A computer for assessing dynamic hyperinflation (DH) in a monitored subject comprising:

a processor; and

a computer-readable memory operatively coupled to the processor and configured with computer instructions that cause the processor to perform the steps of

receiving comparative respiratory data monitored during a current period of monitoring;

determining from the received data at one or more times during the monitoring period a parameter (M%RC) that reflects the relative contributions of expansions and contractions of the rib cage (RC) of the subject to tidal volumes (V_T) of the subject;

determining from the received data at one or more times during the monitoring period another parameter (MqdEELV) that reflects the accumulated changes in end-expiratory lung volume (MqdEELV); and

assessing DH in the subject during the monitoring period in dependence on both the determined MqdEELV parameters and the determined M%RC parameters.

14. The computer of claim 13 wherein the processor and memory are sized and configured so that they can be easily carried by the subject

15. The computer of claim 13 wherein the monitoring period comprises a plurality of sub-periods, and wherein the M%RC parameter and the MqdEELV parameter are determined for each sub-period only from received respiratory data from that sub-period.

16. The computer of claim 13 wherein DH is present during the monitoring period if the M%RC parameter values increase and if the MqdEELV parameter values decrease during the monitoring period.

17. The computer of claim 13 wherein DH is present during a current monitoring period in comparison with a previous monitoring period if the M%RC parameter values during the current monitoring period are greater than during the previous monitoring period and if the MqdEELV parameter values during the current monitoring period are less than during the previous monitoring period.

18. The computer of claim 13

wherein determination of the M%RC parameter comprises dividing the respiratory volumes due to RC expansion and contraction by V_T;

and

wherein determination of the MqdEELV parameter comprises

determining a breath-by-breath change in expiratory lung volume (EELV);

determining a cumulative change in EELV in dependence on a plurality of consecutive breath-by-breath changes in EELV; and

determining the MqdEELV parameter in dependence on the absolute values of a plurality of cumulative changes in EELV.

19. A portable monitoring system for assessing dynamic hyperinflation (DH) in a monitored subject comprising

a wearable item comprising one or more sensors that provide data comprising sizes at one or more selected positions on the torso of the subject, including one or more positions on the RC and one or more positions on the abdomen (AB), the positions being selected so that the torso sizes change with respiration;

a portable data unit operably linked to the sensors, the portable data unit comprising a processing device and a computer memory operably linked to the processing device and configured with computer instructions that cause the processor to perform the steps of

receiving sensor data monitored during a current period of monitoring;

determining V_T in dependence on a difference of a moment-by-moment lung volume parameter at end of inspiration and the lung volume parameter at end of the following expiration, the moment-by-moment lung volume parameter being determined by linearly combining the RC sizes and the AB sizes;

determining from the received data at one or more times during the monitoring period a parameter (M%RC) that reflects the relative contributions of expansions and contractions of the rib cage (RC) of the subject to tidal volumes (V_T) of the subject, wherein determination of the M%RC parameter comprises dividing the respiratory volumes due to RC expansion and contraction by V_T;

determining from the received data at one or more times during the monitoring period another parameter (MqdEELV) that reflects the accumulated changes in end-expiratory lung volume (MqdEELV), wherein determination of the MqdEELV parameter comprises determining a breath-by-breath change in expiratory lung volume (EELV);

determining a cumulative change in EELV in dependence on a plurality of consecutive breath-by-breath changes in EELV; and

determining the MqdEELV parameter in dependence on the absolute values of a plurality of cumulative changes in EELV; and

assessing DH in the subject during the monitoring period in dependence on both the determined MqdEELV parameters and the determined M%RC parameters.

20. The portable monitoring system of claim 19 wherein said wearable item comprises a garment and/or a shirt and/or a band.

21. The portable monitoring system of claim 19 wherein said portable data unit is housed so as to be carried on the wearable item or on an item of clothing worn by the subject.

22. The portable monitoring system of claim 19 wherein said sensors comprise one or more inductive plethysmographic sensors or one or more posture and/or activity sensors.

23. The portable monitoring system of claim 19 wherein said portable data unit stores data on a removable computer-readable memory.

24. The portable monitoring system of claim 19 wherein said portable data unit wirelessly transmits data to a remote computer.