[Comparative study by body plethysmography and spirometry with the helium dilution method in patients with...

The persisting defects after treatment of tuberculosis in 51 patients were evaluated by a simultaneous measurement of the functional residual capacity (FRC) using the body plethysmograph and the helium dilution method. In most patients large volumes of trapped air were detected by the difference of two methods of measurement. The amount of trapped air showed to be dependent of the other pulmonary parameters obtained: Tiffeneau index, FRC measured by body plethysmography, difference between predicted and measured FRC.