Microstream capnography technology: A new approach to an old problem

Significant technical limitations inherent in blackbody infrared technology used in conventional sidestream and mainstream capnography have hindered the acceptance and growth of capnography as a monitoring tool outside the operating room environment. We describe a new technology (Microstream(TM)) for CO2 monitoring, based on molecular correlation spectroscopy, which results in a highly efficient and selective emission of a spectrum of discrete wavelengths exactly matching those for CO2 absorption. The CO2 specific emissions allow for an extremely small sample cell (15 mu l), which in turn, permits the use of a very low sample flow rate (50 ml/min) without compromising waveform integrity or end-tidal CO2 accuracy. Design and technology features of the CO2 emission source, sample cell, and breath sampling circuits are described.