Development of a compact optical sensor for real-time, breath-by-breath detection of oxygen

The detection of oxygen in breath is of central importance to investigations of metabolism and respiration in both clinical and athletic performance monitoring applications. This paper reports the development of a portable, lightweight optical oxygen sensor that is intended to provide a breath oxygen monitoring solution that is deployable outside a laboratory environment. The sensing methodology is based on the detection of changes in the fluorescence emission of an oxygen-sensitive fluorescent dye. The novelty of the system stems from the humidity-insensitive nature of the oxygen sensor, the highly efficient and compact optical configuration and the use of a novel, wearable control unit based on DSP circuitry. These components combine to provide a portable breath oxygen monitor that can detect changes in the in-breath O-2 concentration profile in real-time over a broad range of breathing rates in situations of both rest and exercise. The reported system is expected to have a significant impact on point-of-care (POC) breath-based diagnostics and high performance athletic monitoring.