Citation

Adrian W. Proc. Int. Counc. Alcohol Drugs Traffic Safety Conf. 1981; 1981: 622-636.

Copyright

(Copyright © 1981, The author(s) and the Council, Publisher International Council on Alcohol, Drugs and Traffic Safety)

DOI

unavailable

PMID

unavailable

Abstract

Studies of the time course of breath alcohol concentration (BAC) in relation to the expired volume flow and the exerted pressure were carried out to obtain data to specify the features of breath alcohol measuring devices. Similar experiments were devoted to the influence of the ventilation pattern (hypo- and hyperventilation) on the rise of the BAC. The temperature of the breath in the mouth piece was simultaneously recorded. The findings confirmed a need for a small sample chamber with low back pressure allowing an even flow of breath to ensure undiluted breath samples of the end-expiratory phase. A particular sample control ensures steady readings irrespective of the ventilation pattern. For the measurement of BAC the IR-absorption method, comprising of a dual filter system for reason of alcohol specificity, was applied. Calibrated for blood alcohol concentration using the blood:breath ratio of 1:2.100 the data showed good correlation to the blood values taken in the equilibrium stage and analyzed by gas chromatography. In a comprehensive field test, police officers used this instrument to measure BAC of subjects suspected of drunken driving. Blood samples in or near the equilibrium were taken and routinely sent to a laboratory for analysis. This laboratory using the Widmark and the ADH-method was not aware of the preceding breath alcohol measurements. Although the instrument was still a prototype model and was not yet equipped with the precise sample control the analysis of the data revealed that the standard deviation of the instrument was of the same order as that of The ADH-blood analysis. (TRRL)