Clinical evaluation of a Raman scattering multiple gas analyzer for the operating room

A Raman spectrometer multiple gas analyzer was used to monitor inspired and expired concentrations of oxygen (O2), nitrogen (N2), carbon dioxide (CO2), nitrous oxide (N2O), halothane, and isoflurane in 10 patients. The Raman spectrometer and a dedicated mass spectrometer were connected to each patient to provide a comparison of the two instruments. Results show that readings from the Raman spectrometer are within 0.62 vol% of known gas standards for O2, N2, N2O; within 0.03 vol% for CO2; and within 0.04 vol% for halothane, enflurane and isoflurane. Clinical results show that Raman spectrometer readings are within 1.36 vol% of the mass spectrometer readings for O2, N2, N2O; within 0.01 vol% for CO2; and within 0.22 vol% for halothane and isoflurane. The clinical and laboratory results indicate the Raman spectrometer monitors airway gases and vapors as accurately as a dedicated mass spectrometer.