COMPUTER-CONTROLLED MECHANICAL LUNG MODEL FOR APPLICATION IN PULMONARY-FUNCTION STUDIES

A computer controlled mechanical lung model has been developed for tes ting lung function equipment, validation of computer programs and simu lation of impaired pulmonary mechanics. The construction, function and some applications are described. The physical model is constructed fr om two bellows and a pipe system representing the alveolar lung compar tments of both lungs and airways, respectively. The bellows are surrou nded by water simulating pleural and interstitial space. Volume change s of the bellows are accomplished via the fluid by a piston. The pisto n is driven by a servo-controlled electrical motor whose input is gene rated by a microcomputer. A wide range of breathing patterns can be si mulated. The pipe system representing the trachea connects both bellow s to the ambient air and is provided with exchangeable parts with know n resistance. A compressible element (CE) can be inserted into the pip e system. The fluid-filled space around the CE is connected with the w ater compartment around the bellows; The CE is made from a stretched P enrose drain. The outlet of the pipe system can be interrupted at the command of an external microcomputer system. An automatic sequence of measurements can be programmed and is executed without the interaction of a technician.