Knudson R J, Kaltenborn W T, Burrows B
Division of Respiratory Sciences, (Westend Research Laboratories), University of Arizona College of Medicine, Tucson 85724.
Thorax. 1990 Jul;45(7):514-9. doi: 10.1136/thx.45.7.514.
The single breath transfer factor for carbon monoxide (TLCO), TLCO/alveolar volume (VA), and standard spirometric indices were measured in a survey of the randomly selected population sample of 1174 subjects enrolled in the Tucson epidemiological study of airways obstructive disease. Subjects were subdivided according to whether the FEV1/FVC ratio was under 65%, 65-75%, or over 75%. The influence of smoking on TLCO was accounted for by expressing TLCO as a percentage of the expected value-that is, of the value expected from the reported cigarette consumption. The 63 subjects who gave a history of physician confirmed asthma in reply to a questionnaire tended to have high values for TLCO, even when FEV1/FVC was reduced. In the absence of a given diagnosis of asthma, however, TLCO and TLCO/VA were reduced when the FEV1/FVC ratio was reduced, whether or not a clinical diagnosis of emphysema had been reported. This suggests that these subjects may have undiagnosed emphysema. This cross sectional analysis of our survey data suggests that subjects in our sample with spirometric evidence of chronic airflow obstruction have different forms of disease, characterised by different physiological features, in addition to the different risk factors and clinical courses reported earlier.
在图森气道阻塞性疾病流行病学研究中，对随机选取的1174名受试者的总体样本进行了一氧化碳单次呼吸转移因子（TLCO）、TLCO/肺泡容积（VA）及标准肺量计指标的测量。根据第一秒用力呼气容积/用力肺活量（FEV1/FVC）比值低于65%、65 - 75%或高于75%，将受试者进行了细分。吸烟对TLCO的影响通过将TLCO表示为预期值的百分比来计算，即根据报告的香烟消费量预期得到的值。在问卷中回复有医生确诊哮喘病史的63名受试者，即使FEV1/FVC降低，其TLCO值仍往往较高。然而，在没有明确诊断为哮喘的情况下，当FEV1/FVC比值降低时，无论是否报告有肺气肿的临床诊断，TLCO和TLCO/VA都会降低。这表明这些受试者可能患有未被诊断出的肺气肿。对我们调查数据的这项横断面分析表明，在我们的样本中，有肺量计证据显示存在慢性气流阻塞的受试者除了具有先前报告的不同风险因素和临床病程外，还患有具有不同生理特征的不同形式的疾病。
