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Session: Poster session II
Session starts: Thursday 24 January, 16:00

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Christian Knöbel (Hochschule Furtwangen)
Knut Möller (Hochschule Furtwangen)

Abstract:
For adapting mechanical ventilation to the physiological conditions of the patient’s lung and to avoid damage of lung tissue due to inappropriate ventilator settings, it is necessary to use intelligent and adaptive therapy regimes [1]. These regimes are based on individualised mathematical models representing the patient’s respiratory mechanics. In order to test these algorithms directly with a ventilator machine, active or passive lung simulators are used. As passive lung simulators are not capable of modelling dynamic lung behaviour and diseases, an active lung simulator, based on a cylinder-piston-system has been developed [2], [3]. To achieve high dynamics and low friction, an electromagnetic linear motor is used. In order to keep friction at a minimum level and to create an airtight seal between cylinder and piston, two roll membranes are employed that move with the piston over the whole travel length. They are stabilized using air pressure that is higher than the atmospheric and the maximum ventilation pressure. This reduces the risk of membrane jamming and ensures avoiding air leakages that would influence the ventilator machine. While “ventilating” the simulator, the volume of the artificial lung can be changed by a con-trolled movement of the piston inside the cylinder. Physiological properties of lung mechanics (i.e. compliance) can be modelled by varying the piston velocity. The necessary piston movement is calculated employing a mathematical patient model and a real-time controller. As the dynamics of one cylinder-piston-system is only able to simulate simple respiratory mechanics, several bigger and smaller modules can be combined for modelling more complex structures. Bigger modules can then be used to simulate low-frequent changes in residual vol-ume, whereas smaller modules can simulate high-frequent influences like coughing, sneezing or heart beats.