Method and apparatus for calibrating respiration monitoring system

• US 4,373,534 A
• Filed: 04/14/1981
• Issued: 02/15/1983
• Est. Priority Date: 04/14/1981
• Status: Expired due to Term

• Current Assignee: VivoMetrics, Inc.
• Original Assignee: Respitrace Corporation
• Inventors: Watson, Herman
• Primary Examiner(s): Cohen, Lee S.
• Assistant Examiner(s): Sykes, Angela D.
• Application Number:
  US06/254,133
• Time in Patent Office: 672 Days
• Field of Search: 128/716, 128/719, 128/721-725, 128/694, 128/774-782, 73/728, 73/730-731, 73/735
• US Class Current: 600/538
• CPC Class Codes: A61B 5/0803 Recording apparatus specially adapted therefor
• CPC Class Codes: A61B 5/1135 by monitoring thoracic expansion

Abstract

Improved method for calibrating non-invasive system for measuring respiration volume of the type including apparatus for providing signals indicative of rib cage and abdominal contributions to respiration volume, device for multiplying the rib cage and abdominal signals by predetermined weighting factors reflecting the relative contributions of the rib cage and abdomen to respiration volume, and device for summing the weighted signals for providing a signal proportional to respiration volume. Improved method determines the weighting factors by measuring respiration volume by alternate measuring apparatus, simultaneously recording the unweighted rib cage and abdomen signals and the signal from the alternate measuring apparatus for a first plurality of breaths based on a first relative contribution between rib cage and abdomen and for a second plurality of breaths based on a second relative contribution between rib cage and abdomen, dividing the rib cage and abdomen signals by the signal from the alternate measuring apparatus for each breath for defining first and second coordinates for each breath, and determining the x and y intercepts of a line approximation extending through the plurality of points defined by the coordinates, the reciprocals of the intercepts substantially equaling the weighting factors.

Claims

1. In a non-invasive system for measuring respiration volume of the type including:

means for providing a signal responsive to a rib cage dimension indicative of rib cage contribution to respiration volume;

means for providing a signal responsive to an abdominal dimension indicative of abdominal contribution to respiration volume;

means for multiplying said rib cage and abdominal signals by predetermined weighting factors reflecting the relative contributions of said rib cage and abdomen to respiration volume; and

means for summing said weighted signals for providing a signal proportional to respiration volume;

the improvement comprising means for determining said weighting factors comprising;

alternate means for measuring respiration volume and providing a signal indicative thereof;

means for simultaneously recording said unweighted rib cage and abdominal signals and said signal from said alternate measuring means for a first plurality of breaths based on a first relative contribution between said rib cage and abdomen and for a second plurality of breaths based on a second relative contribution between said rib cage and abdomen;

processing means for (1) dividing said rib cage signal by said signal from said alternate measuring means for each breath for definig a first coordinate for each breath, (2) dividing said abdominal signal by said signal from said alternate measuring means for each breath for defining a second coordinate for each breath, and (3) determining the x and y intercepts of a line approximation extending through the plurality of points defined by said first and second coordinates, the reciprocals of said intercepts substantially equaling said weighting factors.

2. In a method for non-invasively measuring respiration volume of the type including:

providing a signal responsive to a rib cage dimension indicative of rib cage contribution to respiration volume;

providing a signal responsive to an abdominal dimension indicative of abdominal contribution to respiration volume;

multiplying said rib cage and abdominal signals by predetermined weighting factors reflecting the relative contributions of said rib cage and abdomen to respiration volume; and

summing said weighted signals for providing a signal proportional to respiration volume;

the improvement comprising determining said weighting factors by;

measuring respiration volume by alternate measuring means and providing a signal indicative thereof;

simultaneously recording said unweighted rib cage and abdominal signals and said signal from said alternate measuring means for a first plurality of breaths based on a first relative contribution between said rib cage and abdomen and for a second plurality of breaths based on a second relative contribution between said rib cage and abdomen;

dividing said rib cage signal by said signal from said alternate measuring means for each breath for defining a first coordinate for each breath,

dividing said abdominal signal by said signal from said alternate measuring means for each breath for defining a second coordinate for each breath, and

determining the x and y intercepts of a line approximation extending through the plurality of points defined by said first and second coordinates, the reciprocals of said intercepts substantially equaling said weighting factors.