Chest-lung statics: a realistic analog for student laboratory

A mechanical analog of the human lung-chest wall system was developed in Fribourg and Geneva Universities, Switzerland, to help students understand chest-lung statics. The equipment comprises a lung bellows, with upper airway connected to a three-way manifold, and a transparent chest whose lower part is another bellows that can be mobilized manually. Two water manometers measure intrapulmonary and intrathoracic pressures. The pressure-volume relationships of the lung-chest wall analog, which are essentially determined by the diameters of the bellows and the strains imposed by steel coils, closely parallel those of the human respiratory system. The chest can be opened to demonstrate pneumothorax. A first, guided manipulation of the model at the physiology laboratory provides excellent preparation for--or useful complement to--a human subject experiment on chest-lung statics. Unguided, further use of the model provides an opportunity for students to teach each other. Since the model is used, mean score on chest-lung statics at the practical examination is as good as that on other, more easy subjects.