A rapid-response U.V. Halothene meter
The design and performance characteristics of an instrument for monitoring halothene concentrations which operates on the principle of the absorpotion of u.v.light are described. The innovation is that the entire exhaled breath passes through the sample cell, enabling the breath-by-breath halothene concentration to be measured accurately and instantaneously. Stabilized power supplies, solid-state circuitry and filtering make the instrument stable and selective. A value prevents rebreathing of gas exposed previously to u.v.light in the sample cell. Inspired and end-tidal concentrations are displayed digitally and an analog output is available also. Zero and gain drift were negligable after an initial settling period, and interference from other respiratory gases was not detectable. The moniter is suitable for use during anaesthesia for adults and children. © 1978 Macmillan Journals Ltd.