目的:探讨成人用力肺活量（FVC）测定的结束标准。方法:采用多中心横断面研究，连续纳入2017年1—8月在复旦大学附属中山医院、福建医科大学附属第一医院和内蒙古医科大学第三附属医院用肺量测定法进行肺功能检查，且用力呼气量曲线满足出现呼气平台（呼气流量<0.025 L/s、且持续1 s以上）的成人受试者。按通气功能诊断标准分为肺功能正常组（正常组，610名）、阻塞性通气功能障碍组（阻塞组，536例）和限制性通气功能障碍组（限制组，306例），测定不同组受试者的用力呼气时间（FET）；探讨以FET的不同时间段为FVC的结束标准时，阻塞性通气功能障碍诊断的敏感度、特异度和安全性。结果:正常组、阻塞组和限制组的FET分别为（4.00±1.07）s、（8.08±1.56）s和（2.97±0.76）s，95%n CI分别为3.88~4.12?s、7.02~10.14?s和2.21~3.73?s(n F=2 263.80，n P<0.01)。在限制组，随肺功能损害程度加重，FET缩短；在阻塞组，随肺功能损害程度加重，FET延长（均n P<0.05)。以出现呼气平台作为FVC的结束标准时，正常组和限制组不良反应率分别为1.1%和1.3%，均低于阻塞组的17.2%（χn 2分别为92.73和48.49，均n P<0.05）。在阻塞组，FET达6 s、7 s时不良反应发生率分别为4.1%和3.9%（χn 2=0.01，n P=0.93）；其后随呼气时间的进一步延长，不良反应的发生率明显增加。在阻塞组，与FEVn 1/FVC相比，用FEVn 1/FEVn 7诊断的敏感度为99.25%，高于FEVn 1/FEVn 6时97.76%（χn 2=4.06，n P=0.04)；诊断的特异度相同，均为100%。n 结论:FET随肺功能状态改变，以FET≥6 s的固定界值作为成人FVC的结束标准并不合适。对于正常人群和限制性肺疾病患者，应以出现呼气平台作为结束标准；对于阻塞性肺疾病患者，以FET达7 s作为结束标准更为合适。“,”Objective:To explore the end criteria of forced vital capacity(FVC) curve in adults.Methods:A multicenter cross-sectional study was performed in Zhongshan Hospital Affiliated to Fudan University, the First Affiliated Hospital of Fujian Medical University, and the Third Affiliated Hospital of Inner Mongolia Medical University from January 2017 to August 2017. A consecutive sample of subjects who completed the spirometry test and FVC curves met end criteria of no volume change (<0.025 L) for ≥ 1 s were qualified in this study. Subjects were divided into a normal group (n n=610), an obstructive group (n n=536), and a restrictive group(n n=306) according to pulmonary function test results. The FET values in different groups were compared. The side effects in the 3 groups and the diagnostic accuracy, specificity and security of different FET in the obstructive group were assessed.n Results:The FET values of the normal group, the obstructive group, and the restricted group were (4.00±1.07) s, (8.08±1.56) s and (2.97±0.76) s respectively, and the 95% n CI of FET in the 3 groups were between 3.88-4.12?s, 7.02-10.14 and 2.21- 3.73?s (n F=2 263.80, n P<0.01). When the exhalation platform was used as the standard of FVC curve, the adverse reaction rate in the normal group and the restricted group were 1.1% and 1.3% respectively, lower than the rate of 17.2% in the obstructive group (χn 2=92.73, χ n 2=48.49 respectively; all n P<0.05). In the obstructive group, 7 s as the ending criterion had similar incidence of adverse reactions to 6 s (χn 2=0.01, n P=0.93). With further extension of expiration time, the incidence of adverse reactions increased significantly. In the obstructive group, the sensitivity of FEVn 1/FEVn 7 was 99.25%, higher than that at FEVn 1/FEVn 6 (χn 2=4.06, n P=0.04), and the specificity of diagnosis was very similar and 100%.n Conclusions:FET was variable in subjects with different lung function status. It is not appropriate to use a fixed FET≥ 6 s as the end criterion of spirometry for adults. For patients with normal lung function or restrictive lung function defect, exhalation platform should be used as the end of exhalation standard. For patients with obstructive lung function defect, an FET of up to 7 s is appropriate.