Methods and systems for determining dynamic hyperinflation
First Claim
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 (VT) 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.
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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.
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Citations
25 Claims
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1. A computer-implemented method for assessing dynamic hyperinflation (DH) in a monitored subject comprising:
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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 (VT) 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. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 25)
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13. A computer for assessing dynamic hyperinflation (DH) in a monitored subject comprising:
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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 (VT) 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. - View Dependent Claims (14, 15, 16, 17, 18)
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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 VT 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 (VT) of the subject, wherein determination of the M%RC parameter comprises dividing the respiratory volumes due to RC expansion and contraction by VT;
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. - View Dependent Claims (20, 21, 22, 23, 24)
Specification