15min:

RICHARD D. SUENRAM, DALE J. BRUGH AND F. J. LOVAS, National Institute of Standards and Technology, Optical Technology Division, Gaithersburg, MD 20899-8441; CHING CHU, Datex-Ohmeda, Ohmeda Drive, Madison, WI 53707-7550.

The rotational spectra of five common inhalation anesthetics used during surgical procedures have been surveyed between 10 and 20 GHz using a Fourier-transform microwave (FTMW) spectrometer. The anesthetics are desflurane (CF₂HOCHFCF₃), isoflurane (CF₂HOCHClCF₃), sevoflurane (CH₂FOC(CF₃)₂H), enflurane (CF₂HOCF₂CFClH), and halothane (CBrClHCF₃). At the present time, the rotational spectra of desflurane and sevoflurane have been assigned and analyzed. For sevoflurane the rotational constants are A = 1025.6 MHz, B = 899.5 MHz and C = 601.3 MHz. Analysis of the spectra for the other three species is in progress. Real-time detection limits in air are in the µmol/mol regime which are more than adequate for this application where levels approach 1000 µmol/mol in the patient's breath. The ultimate goal is to demonstrate that FTMW spectroscopy is a viable alternative to molecular vibration infrared spectroscopy for performing real-time monitoring of the concentrations of these anesthetics in a patient's breath during surgical procedures.