Patent ID: 7681574
Filing Date: 2010-03-23
Classification: A61B,A61M

Abstract:
1. A method for determining the functional residual capacity of a subject's lungs using a washout/wash-in technique in which a concentration of a tracer gas in the inspired breathing gases for the subject is altered from an initial concentration, said method comprising the steps of: (a) providing a functional residual capacity (FRC) measuring circuit having a central processing unit (CPU); (b) determining in the CPU, for each of a plurality of breaths of a series of breaths, a value of a volume dilution factor k (c) determining in the CPU, for each breath of the plurality of breaths, a value of the functional residual capacity of the subject's lungs; (d) establishing a predetermined value for the volume dilution factor k (e) determining in the CPU when the value of the volume dilution factor k (f) establishing a relationship in the CPU between the determined value for the volume dilution factor k (g) estimating the functional residual capacity of the subject's lungs in the CPU at the predetermined value for the volume dilution factor k