A clinical gas analyzer will be developed consisting of an acousto-optic tunable filter (AOTF) infrared spectrometer fiber-coupled to an airway mounted sample cell. The ability of the AOTF to rapidly obtain detailed spectral data will permit the identification and quantification of the anesthetic agents, carbon dioxide, and nitrous oxide. Infrared transmitting fluoride glass fibers will be optimized for use in the 2-5 micron spectral region. The advantages of the AOTF for this and other clinical applications include small size, high speed, no moving parts, and good spectral resolution. The use of on-airway sampling instead of vacuum tubing will minimize transit delays. During Phase II, we will develop the system electronics, software, and optics and optimize the AOTF and flow cell to achieve high accuracy, speed, and agent identification.