Case 13: You Smell Anesthesia Vapor – Where Is It Coming From?

Abstract

A 45-year-old patient, American Society of Anesthesiologist (ASA) physical status 2, is to undergo a removal of a cerebral tumor under general anesthesia. An anesthesia machine (Drager Fabius GS, Telford, PA 18969) and breathing system check are performed before the patient’s arrival. The Drager Vapor 2000 (Drager Medical AG, Lubeck, Germany) sevoflurane vaporizer is seen to be full. Noninvasive monitors are placed, and after preoxygenation the patient is anesthetized in a routine manner. Invasive monitors (arterial line and central venous line) are placed, and the operating table is turned 180° from the anesthesia machine. The operation proceeds uneventfully. Two hours into the case, you suddenly smell anesthesia vapor around the anesthesia machine. You think you can smell more vapor around the vaporizer, but you are not sure. All vital signs are within normal limits. There are no warnings to indicate low minute volumes, apnea, or no ventilation of the patient. The rotameters show adequate flow and the pipeline pressure is 50 psi. The expired tidal volume is 600 ml, peak pressure is 25 cm, and the respiratory rate is 8. End-tidal CO2 and sevoflurane concentrations are within normal limits. (Datex Capnomac Ultima, Helsinki, Finland).