SPIROLUFT : A Next Generation Breath Analyser Utilising Simultaneous Spirometry & Pulse Oximetry

Sammanfattning

Given the rapid advancements in computation processing capabilities of microcontrollers, an advantage can be taken for further innovation within the medical sector. The trend has enabled medical instruments to move from a clinical setting into a more remote setting. Embedded solutions are now able to increase the availability of mobile diagnostics tools by reducing time and in turn cost. This work focuses on enabling remote diagnosis of lung function to determine pulmonary function diseases such as asthma and chronic obstructive pulmonary disease (COPD). By utilising embedded system fundamentals, a mobile extended spirometer called the Spiroluft was developed for simultaneous measurement of spirometry and pulse oximetry metrics, in order to evaluate lung function. A combination hopes to assist decision-makers in making correlation between the two more available. Remote instruments in literature and market have not yet applied the combination, making a detected correlation difficult to access. The developed instrument will in its final form be used as a medical instrument, which means that a set of Medical Device Regulation (MDR) standards will have to be met. This work has therefore taken these requirements into account at an early stage as a form of project specification. Given the specification, a design was constructed followed by implementation. To assess the performance of the system, the work also includes a comprehensive evaluation. This included an offline and online real-time analysis, together with a spirometer and a pulse oximeter evaluation as simplified MDR specified tests. Results were extracted to assess accuracy to be compared with MDR standards. The results proved that an extend spirometer adopting simultaneous detection of both methods was successfully developed, leaving space for additional simultaneous sensory parameters. A possible sampling rate of up to 166 Hz was achieved for flow measurements, implying a great resolution and accuracy of spirometry metrics. Comparing the pulse oximeter to another MDR compliant instrument indicated a detection error well within the MDR standards. One impacting factor identified and investigated was related to the wireless Bluetooth Low Energy communication. Another impact was the difficulty applying satisfactory MDR compliance, as extensive resources in the form of funds and time were required. Aside from the resource limitations, a majority of the MDR requirements were satisfied and others partly, suggesting that the instrument is well under way to become a fully compliant remote medical instrument for detection of pulmonary function disease.