Rationale for developing tunable laser spectroscopy (TLS) technology for high resolution real-time carbon dioxide monitoring (capnography) in human breath.

Real-time monitoring of exhaled carbon dioxide (CO2), also known as capnography, is a valuable hospital tool for assessing patient health during anesthesia and in both the emergency department and critical care units. The fundamental measurement is referred to as end-tidal carbon dioxide concentration that reflects pulmonary gas exchange of CO2representing systemic metabolism. The shape of the exhaled CO2concentration for individual inhalation/exhalation breath cycles can offer additional information regarding lung function, airway obstruction, alveolar ventilation, and worsening disease. The most frequent use is to indicate appropriate placement of an endotracheal tube but and it is also employed in the assessment of disease severity and response to treatment (e.g. asthma). Other applications include outpatient monitoring with oxygen supplementation (nasal cannula) and continuous positive airway pressure control for sleep apnea. As technology has evolved, CO2measurements have become more mobile; capnography systems are now used by emergency medical services personnel for verifying proper placement of airway devices in 'pre-hospital' environments. The use of CO2diagnostics has evolved to identify breathing system disruptions in 'on-demand' regulator/masks equipment, both in medical and occupational settings. Most recently, miniaturized tunable laser spectroscopy sensors have been implemented for assessing pilot breathing in high-performance military aircraft. This editorial describes the use of CO2breath sensors and proposes some new applications based on miniaturized sensors that can be directly inserted into breathing masks.