The history of the pulmonary diffusing capacity for nitric oxide DL,NO

The DL,NO (TL,NO) had its unexpected origins in the Paris “events” of 1968 and the unsuccessful efforts of the UK tobacco industry in the 1970's to create a “safer cigarette”. Adoption of the technique has been slow due to the instability of NO in air, lack of standardisation of the technique and lack of agreement as to whether DL,NO is equal to or merely reflects membrane diffusing capacity (DM). With the availability of inexpensive analysers, standardisation of the technique and publication of reference equations we believe that its worldwide use will increase.