Medical technology Applications

Lung Function Testing

NM GmbH supports Eco Medics AG, Dürnten in the development of novel signal processing algorithms to improve lung testing measurements. Typically, lung function testing is based on the detection of the expiration gas composition as a function of the air volume. From these measurements dead spaces, lung clearing indexes, etc. are inferred. Due to variations of the air temperature and its relative humidity as well as artifacts of the transducers, the collected raw signals have to corrected to achieve optimal diagnostic quality.

The chosen approach includes physical reasoning, signal filtering techniques as well as numerical schemes to allow for on-line signal processing. An integral part of the signal correction algorithm is furthermore an efficient simulation of unobservable quantities, e.g., the air flow temperature at the sensing element position.

Lung Modelling

In a close collaboration with the Universitäts-Kinderklinik of Inselspital Bern and the Eco Medics AG, Dürnten, NM GmbH develops numerical models of gas transport processes in the human lung. The focus lies on the understanding of so-called double-inert-gas effects: lung ventilation properties are identified by replacing part of the air's nitrogen by a mixture of He and SF6 of equal mean molar mass. The expired gas composition then reflects the lung ventilation by exposing diffusion fronts by the temporal succession and relat­ive strength of He and SF6 species. These quantities are assessed indirectly by an acoustic method measuring the mean molar mass signal.

NM GmbH supports the medical research by physical and physiological modeling of the relevant gas transport processes including convection, multi-species diffusion and alveolar gas exchange. The goal of this approach is the identification of robust signal properties that reflect the lung ventila­tion homogeneity.





Signal correction (model based filtering)
Section of Tool-GUI
Exhalyzer (Eco Medics AG)