Method and apparatus for calibrating respiration monitoring system

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.