Electronic measurements of pulmonary mechanics

The phenomenon of a fixed upper limit to the volume flow rate of gas at a subject´s mouth during a forceful exhalation has been used for many years in a variety of pulmonary function tests as a method to assess the physical condition of lung tissue and airways. The volume flow rate limit varies with lung volume and the time region over which this maximal exhalation occurs is referred to as “effort-independent”. The values and shape of the changing maximal expiratory flow vs. volume and time curves are used to assess the physical condition of the lungs. Here a method is partially described for the measurement of dynamically changing lung mechanical parameters during maximal and slow exhalations. It is seen that the use of methods of electronic measurements and numerical methods of computer analysis are indispensable to the interpretation of these measurements. It is also suggested that these methods can take the place of several separate pulmonary function tests at one sitting and provide a possible means for the early detection of lung disease