LED-based sensing system for biomedical gas monitoring: Design and experimentation of a photoacoustic chamber

An efficient and portable photoacoustic multi-gas monitor for biomedical application is needed in hospital in order to detect indoorgas pollution, r to protect the health of workers, patients and visitors. If the highest precision is not required. especially for continuous monitoring of anaesthetic gases, a LED-based (light emitting diode) detecting system can be employed in order to estimate an attention threshold level of gas. This paper illustrates a design and characterization of a led-based photoacoustic chamber (sensing-actuating system and cell) for anaesthetic gas detection. A measurement campaign has been conducted in a surgery room; the results have been compared with another photoacoustic instrumentation used simultaneously. The main asset of the new system is a double source of LED light instead of a more traditional system. (c) 2008 Elsevier B.V. All rights reserved.