Low E C T, Ong M C C, Tan M
Naval Medicine and Hyperbaric Centre, AFPN, Sembawang Camp, 36 Admiralty Road West, Singapore 759960.
Singapore Med J. 2004 Dec;45(12):578-82.
The breath carbon monoxide (CO) monitor has been shown to be an effective tool in predicting smoking habits. This study aims to assess whether the breath CO level can be employed to determine a person's smoking habit in the military setting and to analyse various factors that can influence the breath CO levels.
155 navy personnel were questioned on their smoking habits in phase one of the study. The subjects were explained the objective of the study and instructed to provide two breaths into the CO monitor (EC-50 Smokerlyser, Bedford Instruments, Kent, UK). In a subsequent single blind study, 40 trainees were not told of the purpose of the study and were assessed via a questionnaire and smokerlyser estimation. Descriptive statistics were used to examine the data and assess distribution. Depending on the distribution, a two-sample t test or Mann-Whitney U test were used to test for a significant difference between CO levels among smokers and non-smokers.
In phase one, the mean breath CO levels were 11.6 (plus or minus 6.2) ppm for smokers and (1.9 plus or minus 0.9) ppm for non-smokers (p-value less than 0.0001). A cut-off level of 5 ppm gave a sensitivity of 96 percent and a specificity of 98 percent. The high CO levels were clustered within five hours of the last cigarette smoked. Therefore, this value may not reliably predict smoking habits if an individual smoked more than five hours before the test. Of the 40 subjects in phase two, five smokers who stated that their last cigarette smoked was 48 hours before the breath test had a mean CO level greater than 5 ppm. (range of 5.5 to 18.0 ppm). On further questioning, all admitted to having smoked on the day of the test.
The breath CO monitor has good potential for use as an adjunct in future smoking control assessments and a reading greater than 5 ppm strongly suggests that the military outpatient is a smoker.
呼气一氧化碳（CO）监测仪已被证明是预测吸烟习惯的有效工具。本研究旨在评估呼气CO水平是否可用于确定军事环境中人员的吸烟习惯，并分析各种可能影响呼气CO水平的因素。
在研究的第一阶段，对155名海军人员的吸烟习惯进行了询问。向受试者解释了研究目的，并指导他们向CO监测仪（EC-50型吸烟者分析仪，贝德福德仪器公司，英国肯特）呼气两次。在随后的单盲研究中，40名受训人员未被告知研究目的，通过问卷调查和吸烟者分析仪评估。使用描述性统计分析数据并评估分布情况。根据分布情况，采用两样本t检验或曼-惠特尼U检验来检验吸烟者和非吸烟者之间CO水平的显著差异。
在第一阶段，吸烟者的平均呼气CO水平为11.6（±6.2）ppm，非吸烟者为（1.9±0.9）ppm（p值小于0.0001）。截断值为5 ppm时，敏感性为96%，特异性为98%。高CO水平集中在最后一支烟吸食后的5小时内。因此，如果个体在测试前吸烟超过5小时，该值可能无法可靠地预测吸烟习惯。在第二阶段的40名受试者中，有5名吸烟者表示他们最后一支烟是在呼气测试前48小时吸食的，其平均CO水平大于5 ppm（范围为5.5至18.0 ppm）。进一步询问后，所有人都承认在测试当天吸烟了。
呼气CO监测仪在未来吸烟控制评估中作为辅助工具具有很大潜力，读数大于5 ppm强烈表明军事门诊患者是吸烟者。
