Patent ID: 8141552

Claim:
An apparatus for the respiratory anesthesia of a patient by administration of a gas containing gaseous xenon comprising: a main gas circuit (CP) in an open or closed circuit having an inhalation branch for leading a first gas mixture containing xenon to the patient and an exhalation branch for conveying a second gas mixture containing xenon exhaled by the patient; means for supplying gaseous xenon connected to the main circuit for supplying the inhalation branch of the main circuit with the first gas mixture containing xenon; means for determining the xenon concentration in order to determine the gaseous xenon content in at least part of the main circuit; wherein said means for determining the xenon concentration comprises: at least one hot-wire sensor having at least one electrically conducting wire, in direct contact with at least part of the first or second gas flow containing xenon; and calculating means cooperating with the hot-wire(s) sensor for determining the xenon concentration (Xe %) in said first or second gas flow containing xenon; means capable of and designed for generating an electric current in at least one hot wire of said at least one hot-wire sensor, means for measuring the voltage capable of measuring at least one voltage value (V) at a terminal of at least one hot wire of said at least one hot-wire sensor or at a terminal of at least one resistance arranged in series with the at least one hot wire of said at least one hot-wire sensor when said at least one hot wire is a) in contact with the first or second gas flow containing xenon and b) traversed by an electric current of intensity (I), and in that the calculating means cooperate with the means for measuring voltage so as to determine, from the voltage measurement (V) carried out by said voltage measuring means, the xenon concentration (Xe %) in said first or second gas flow containing xenon.