Kainu Annette, Lindqvist Ari, Sarna Seppo, Sovijärvi Anssi
Division of Pulmonary Medicine, Department of Medicine, Helsinki University Central Hospital, Helsinki, Finland.
Clin Physiol Funct Imaging. 2008 Jan;28(1):38-42. doi: 10.1111/j.1475-097X.2007.00771.x.
Forced expiratory time (FET) has gained new interest in the joint recommendation of the American Thoracic Society (ATS) and the European Respiratory Society (ERS) for the assessment of spirometry. Interpretation of FET is, however, difficult as limited information is available on spirometric and anthropometric determinants of FET in populations.
We studied a non-selected population sample including healthy non-smokers with a structured interview and flow-volume spirometry. Regular medication, if any, was continued. Spirometry of 603 individuals (248 men, 355 women) fulfilled predefined quality criteria based on modified ATS recommendations. FET from the flow-volume curve with the largest sum of forced expiratory volume in 1 s (FEV1) and forced vital capacity (FVC) was used in analyses.
The mean FET in the population sample was 10.7 (95% CI 10.4-11.1) s and in healthy non-smokers 9.8 (9.2-10.4) s. Men had on average longer FET (11.3 s versus 10.3 s), but the gender difference was not significant when FEV1/FVC was used as a covariate. FEV1/FVC (r = -0.613, P<0.01) and maximal mid-expiratory flow (MMEF) correlated negatively and age (r = 0.279, P<0.01), body mass index (BMI) and smoking pack-years positively with FET.
The findings indicate that mean FET is around 11 s in a non-selected adult population and around 10 s in healthy non-smokers. FET increases slightly with age and BMI, suggesting age- and weight-related changes in pulmonary mechanics. The negative correlation of FET with FEV1/FVC and MMEF even in healthy non-smokers indicates that airflow limitation, either pathological or physiological, tends to prolong FET.
用力呼气时间（FET）在美国胸科学会（ATS）和欧洲呼吸学会（ERS）联合发布的肺功能测定评估建议中受到了新的关注。然而，由于关于人群中FET的肺功能测定和人体测量学决定因素的信息有限，FET的解读存在困难。
我们研究了一个未经选择的人群样本，包括健康非吸烟者，进行了结构化访谈和流量-容积肺功能测定。如有常规药物治疗，继续进行。603名个体（248名男性，355名女性）的肺功能测定符合基于修改后的ATS建议的预定义质量标准。分析中使用了来自流量-容积曲线且1秒用力呼气量（FEV1）和用力肺活量（FVC）总和最大的FET。
人群样本中的平均FET为10.7（95%可信区间10.4 - 11.1）秒，健康非吸烟者为9.8（9.2 - 10.4）秒。男性的FET平均较长（11.3秒对10.3秒），但当将FEV1/FVC用作协变量时，性别差异不显著。FEV1/FVC（r = -0.613，P<0.01）和最大呼气中期流量（MMEF）与FET呈负相关，年龄（r = 0.279，P<0.01）、体重指数（BMI）和吸烟包年数与FET呈正相关。
研究结果表明，在未经选择的成年人群中，平均FET约为11秒，在健康非吸烟者中约为10秒。FET随年龄和BMI略有增加，提示肺力学存在与年龄和体重相关的变化。即使在健康非吸烟者中，FET与FEV1/FVC和MMEF的负相关也表明，无论是病理性还是生理性的气流受限都倾向于延长FET。
