[A new method to estimate blood alcohol concentration from the breath of unconscious subjects (author's transl)].

The method of rebreathing and its particular importance to the estimation of blood alcohol concentration (BAC) are described. A face mask with an accompanying valve chamber to which a collection bag was attached proved to meet the requirements arising from the physiological exchange processes in rebreathed air. Practical tests in the laboratory revealed excellent agreement between the values obtained by direct measurements of breath alcohol by means of an IR-Spectrophotometer and those from stored samples.