| 摘要 |
<PICT:0741510/III/1> Apparatus for sampling exhalation air comprises a three-way member 2, branch 1 being for connection to the mouth, branch 3 leading to a gas-tight collapsible bag or evacuated container 4, and the third branch 5 leading to a sample container 7 and being provided with a resistance to air flow. The resistance may be an excess pressure valve 6, as shown, or a nozzle or capillary tube. On exhaling into branch 1 the air first fills bag or container 4 and only then flows past the resistance in the sampling tube into the container 7, thus ensuring that only alveolar </>air is sampled; the sample may be removed at 9 for analysis. A tube containing a reagent which changes colour in the presence of a constituent of exhaled air may be used as the flow resistance, Fig. 2 (not shown); if the volume of air passing through the tube is known, the colour change indicates the concentration of a constituent, for example, alcohol or carbon dioxide. |
