The optical measurement of 1,2-propanediol for the determination of lung capillary permeability surface area

A technique that allows for the optical measurement of the concentration-time relationship for a diffusion-limited material in indicator dilution studies is discussed. The material, 1-2 propanediol, is used as a probe of the permeability of capillaries in the lung. Comparisons between standard radioisotope measurements and the optical measurements are provided and show excellent agreement. The optical method represents an improvement over the standard radioisotope method in that it provides the same data at lower cost, lower risk, and without the delay required by the radiographic methods.