Precise determination of refractometric parameters for anesthetic agent vapors.

The absolute refractive indices of the anesthetic agent vapors isoflurane, sevoflurane, enflurane, halothane, and desflurane are determined to a typical uncertainty of 1 part in 10(7) over the respective temperature and pressure ranges of 15-40 °C and 5-45% of their saturated vapor pressures at wavelengths of 632.99, 594.10, and 543.52 nm. The specific refraction, second virial coefficients, and dispersion constants are also derived for each agent, from which an equation for the calculation of agent refractivity is established that is in agreement with the measured data to within 2 × 10(-8).