Abstract: Method and apparatus for determining in a person's exhalation air the concentration of a specific substance in the blood by measuring the concentration of said substance and the concentration of water vapor in the exhalation air and utilizing a known relationship between these concentrations. When the method is applied the exhalation air is exhaled freely in a defined air volume having a predetermined composition, and said concentrations are measured in this air volume. The apparatus for working the method comprises a device (16) which defines a space for receiving the exhalation air, which has two mutually opposite openings through which the space communicates with the surrounding air, and means (18, 22, 23) for selective quantitative detection of said substance in the air in the defined space.

Abstract: A method in calibrating or checking an apparatus for determining in a person's exhalation air the concentration of a specific substance is disclosed. The apparatus comprises means for passing exhalation air along a free measuring length, and means for supplying air of a predetermined composition to the measuring length to produce an air flow along the length. A mixture of the substance and water in a specified concentration thereof inder instantaneous evaporation is injected into the air when supplied to the measuring length. The concentration of the substance and the concentration of water vapor in the air flow along the measuring length is determined. The substance gas flow and the water vapor flow are calculated, and the ratio thereof is compared with the specified concentration of the mixture.

Abstract: In a method an apparatus for vaporizing anesthetic liquids, in which a carrier gas is passed through a vaporizer so as to be saturated with vaporized anesthetic liquid, the vaporizer has a container, partially filled with anesthetic liquid, an inlet for a carrier gas, an outlet for carrier gas saturated with anesthetic and a pressure chamber. The carrier gas is supplied to the vaporizer at a pressure exceeding atmospheric pressure and is bubbled through the anesthetic liquid in the container in order to become saturated with anesthetic. The flow of gas at the outlet can be regulated as needed. Exact pressure and temperature conditions can be measured and/or regulated with a pressure meter, pressure regulator, thermometer and temperature regulator in order to regulate the partial pressure of anesthetic in the container.