Estimation on the diagnostic value of physical properties of endogenously generated exhaled aerosols in occupational lung disease

Status:

completed 03/2024

Aims:

Respiratory diseases such as pneumoconiosis and obstructive airway disease are among the most common and important occupational diseases, with the lung periphery often being a highly relevant site, especially in the early stages. However, common methods of lung function testing, such as spirometry and body plethysmography, only detect changes in the periphery of the lungs to a limited extent. Due to their formation in the terminal airway structures, the properties of exhaled aerosols could be particularly suitable for the diagnosis of early structural and ventilatory changes in the lung periphery.

A feasibility study conducted by the Fraunhofer Institute for Toxicology and Experimental Medicine (ITEM) in collaboration with the Institute for Prevention and Occupational Medicine (IPA) of the German Social Accident Insurance (DGUV) investigated whether the physical analysis of exhaled particle size is suitable for the early detection of occupational lung diseases.

Activities/Methods:

In the first step, the experimental setup for the physical characterization of exhaled aerosols was revised for better usability and a clinical study was conducted at the ITEM to optimize the breathing protocol and data evaluation. The aim of the subsequent feasibility study at the IPA was to clarify the basic suitability of particle analysis in exhaled breath for the detection of occupational, peripheral lung diseases. For this purpose, persons with specific occupational diseases (BK nos. 4103, 4301, 4302) who had previously been assessed at the IPA were recruited and the exhaled aerosols were characterized according to the breathing protocol defined in the preliminary study.

Results:

In summary, a suitable, easy-to-use measurement setup was created for analysis of the exhaled particles properties. The impact of cross-sensitivities on the particle signal was thoroughly studied, leading to the identification of suitable breathing protocols and correction options for deviations from key variables (such as bolus volume and flow rate) during exhalation analysis. The feasibility study showed that, contrary to expectations, only a few test subjects could be recruited from people with specific occupational diseases who had previously been assessed at the IPA. The number of data sets generated is not sufficient to assess the suitability of particle analysis in exhaled breath for the detection of occupational, peripheral lung diseases. Due to the need for ambient air with a low particle background, and the quality requirements for the breathing maneuver to be performed, the use of the new diagnostic procedure in routine operation is unlikely. However, usability of the procedure for early detection or for mechanistic investigations as part of research projects cannot be ruled out.

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