Which Parameters Should Be Used to Represent a Typical Breath Flow

Abstract

There are many parameters that be used to represent typical breath flow, mainly divided into three types: one is temporal, the second is frequency, and the last is pressure driven model. The temporal parameters include breath period, tidal volume, inspiration expiration ratio, and functional residual volume, to name a few. The frequency parameters mainly include every harmonic content variation. The pressure driven model use mechanical parameters to calculate flow. All the methods above have one common disadvantage: they do not take variation into account. We proposed here that the fourth type parameter should be also used to describe flow pattern, namely fractal parameter, fractal dimension of breath flow signal. The necessity and advantage of the fractal parameter is elucidated. The fractal dimension parameter is optional because of its stability compared with other parameters.