Faculty Collaboration Database

Mass spectrometry provides warning of carbon monoxide exposure via trifluoromethane. Anesthesiology 1996 Jun;84(6):1489-93

Date

06/01/1996

Pubmed ID

8669691

DOI

10.1097/00000542-199606000-00026

Scopus ID

2-s2.0-0029982759 (requires institutional sign-in at Scopus site)   27 Citations

Abstract

BACKGROUND: The chemical breakdown of isoflurane, enflurane, or desflurane in dried carbon dioxide absorbents may produce carbon monoxide. Some mass spectrometers can give false indications of enflurane during anesthetic breakdown.

METHODS: During clinical anesthesia with isoflurane or desflurane, the presence of carbon monoxide in respiratory gas was confirmed when enflurane was inappropriately indicated by a clinical mass spectrometer that identified enflurane at mass to charge ratio = 69. In vitro, isoflurane, enflurane, or desflurane in oxygen was passed through dried carbon dioxide absorbents at 35, 45, and 55 degrees C. Gases were analyzed by gas chromatography and by mass spectrometry.

RESULTS: Mass spectrometry identified several clinical incidents in which 30-410 ppm carbon monoxide was measured in respiratory gas. Trifluoromethane was produced during in vitro breakdown of isoflurane or desflurane. Although these inappropriately indicated quantities of "enflurane" correlated (r2 > 0.95) to carbon monoxide concentrations under a variety of conditions, this ratio varied with temperature, anesthetic agent, absorbent type, and water content.

CONCLUSIONS: Trifluoromethane causes the inappropriate indication of enflurane by mass spectrometry, and indicates isoflurane and desflurane breakdown. Because the ratio of carbon monoxide to trifluoromethane varies with conditions, this technique cannot be used to quantitatively determine the amount of carbon monoxide to which a patient is exposed. If any warning of anesthetic breakdown results from this technique then remedial steps should be taken immediately to stop patient exposure to carbon monoxide. No warning can be provided for the breakdown of enflurane by this technique.

Author List

Woehick HJ, Dunning M 3rd, Nithipatikom K, Kulier AH, Henry DW

Author

Harvey J. Woehlck MD Professor in the Anesthesiology department at Medical College of Wisconsin

MESH terms used to index this publication - Major topics in bold

Anesthetics, Inhalation
Carbon Monoxide
Chlorofluorocarbons, Methane
Enflurane
Humans
Isoflurane
Mass Spectrometry