A modern gas mixing apparatus with rapid mass flow controllers was used to verify the procedure.

A computer algorithm sought an appropriate value of deadspace to satisfy the mass balance equation for each breath. The new method used integration of flow and concentration. In this paper, we proposed a modification of the Bohr method, relaxing the requirement of absolute uniformity of tracer concentration in the inspired breath. One such lung function measurement technique is the inspired sinewave technique.

However, in some lung function measurement techniques where inspired concentration of the tracer gas may be required to vary, or where rapid injection of the tracer gas is made in real time, uniform inspired concentration is difficult or impossible to achieve, which leads to inaccurate estimation of deadspace using the Bohr equation. It is based on the assumption that the inspired concentration of the tracer gas is constant throughout inspiration.

The Bohr method is a technique to determine airways deadspace using a tracer gas such as carbon dioxide or nitrogen.

How to calculate anatomical dead space