Measurement of anesthetics in blood using a conventional infrared clinical gas analyzer

Abstract

BACKGROUND: Measurement of the partial pressure of volatile anesthetics in blood is usually done using a "headspace equilibration" method with gas chromatography. However, it is not often performed in clinical studies because of the technical, equipment, and logistic requirements. To improve the accessibility of this measurement, we tested the use of a common infrared clinical gas analyzer, the Datex-Ohmeda Capnomac, for this purpose. METHODS: After characterization of the linearity of the device in measuring the volatile anesthetic concentration in the presence of nitrous oxide, carbon dioxide, and water vapor, blood was tonometered with known concentrations of sevoflurane (actual value bet..