Method of determining functional residual capacity of lungs during breathing, useful in newly-born or premature babies and for determining intra-pulmonal gas distribution disorders, employs fluoro-propane

摘要

A method (I) of determining functional residual capacity of the lungs comprising the use of fluoro-propane (II). Preferred Method: (I) comprises: (1) production of a predetermined concentration of fluoro-propane in the lungs by flushing them to saturation; (2) measurement of fluoro-propane volumes (V1 - Vn) in expired gases for successive breaths (A = 1 - n) in subsequent flushing-out phases, using a sensor (14); (3) determination of the corresponding concentrations K1 - Kn of fluoro-propane in each breath, using a computer; (4) determination of the time of breathing the mean concentration of fluoro-propane is multiplied by the relevant volumes; (5) calculating a value for the functional residual capacity (FRC), the quotient of the calculated, expired volume of fluoropropane and the difference between the fluoropropane concentration K0 at the start of the flushing-out phase and that KA during the breath A; and (6) repetition of the above stages until the result FRC lies in a given band of tolerance, 5-20% of the last calculated value FRCn.