[Technique and clinical importance of breathing wave generators]

In recent years, several comparisons of ventilators for invasive and noninvasive mechanical ventilation or automatic continuous pressure therapy (APAP) were published. Simulations were used with different test sequences. Simulations are particularly helpful when identical breathing patterns should be reproduced several times. In the following we report on recent developments of flow- and lung simulators from other groups and present our own experiences in Hagen. To study automatic CPAP devices we applied a custom-made simulator which reproduces the obstruction of the upper airway and any breathing waveform. From the different behavior of automatic CPAP devices concerning pressure dynamics important conclusions can be drawn about the real clinical situation.