González Ruiz J M, Barrueco M, Cordovilla R, Hernández-Mezquita M A, Rivas P, Gómez F
Servicio de Neumología, Hospital Universitario, Salamanca.
Rev Clin Esp. 1998 Jul;198(7):440-2.
The objective of our work was to know the relationship between carbon monoxide (CO) levels in expired air and smoking habits among school youths and the relationships that can be established between CO level and some peculiar attitudes regarding consume by youths, such as the number of cigarettes, inhaling technique and time elapsed since the last cigarette was smoked. The study, of cross-sectional design, was performed in two high school centres and a total of 777 students who answered a questionnaire and had an expired air CO sample in their own schoolroom tested were enrolled. CO determination in the schoolroom was a simple and attainable technique for the pupils, as only 32 cases (4.1%) had to be excluded due to poor collaboration or poor technique. The mean (mean and SD) CO level in the control group (n = 247), made up by non-smokers nor tobacco tasters was 4.75 (2.46) ppm, statistically lower than among smokers (p < 0.001), but with no differences compared with non smokers (n = 563), who had a CO level of 5.23 (3.4) ppm. This figure was also lower (p < 0.001) than that obtained in the smokers (12.6 [6.3] ppm), made up of 214 pupils, with a mean consume of 2.7 (1.69) cigarettes/day. Among smokers the mean abstinence time since the last cigarette was smoked was 26 (44) minutes and 54% of them admitted to have smoked in the last 10 minutes. CO in expired air correlated significantly with the number of smoked cigarettes (r = 0.58; p < 0.001). Likewise, it correlated significantly with abstinence minutes (r = -0.38; p < 0.001). The time required for CO level to decrease below 10 ppm was 140 minutes in four cases and 120 minutes in 33 cases.
我们研究的目的是了解在校青少年呼出气体中一氧化碳（CO）水平与吸烟习惯之间的关系，以及CO水平与青少年一些特殊消费态度（如吸烟数量、吸入技巧和上次吸烟后经过的时间）之间可能建立的关系。这项横断面设计的研究在两个高中中心进行，共招募了777名学生，他们回答了一份问卷，并在自己的教室里进行了呼出气体CO样本检测。在教室里测定CO对学生来说是一种简单可行的技术，因为只有32例（4.1%）因合作不佳或技术欠佳而被排除。由非吸烟者和非烟草品尝者组成的对照组（n = 247）的平均（均值和标准差）CO水平为4.75（2.46）ppm，在统计学上低于吸烟者（p < 0.001），但与CO水平为5.23（3.4）ppm的非吸烟者（n = 563）相比无差异。这个数字也低于214名学生组成的吸烟者组（12.6 [6.3] ppm）（p < 0.001），吸烟者平均每天吸烟2.7（1.69）支。在吸烟者中，自上次吸烟后的平均禁吸时间为26（44）分钟，其中54%的人承认在过去10分钟内吸过烟。呼出气体中的CO与吸烟数量显著相关（r = 0.58；p < 0.001）。同样，它与禁吸分钟数也显著相关（r = -0.38；p < 0.001）。4例CO水平降至10 ppm以下所需的时间为140分钟，33例为120分钟。
