Pulmonary/Critical Care Service, Brooke Army Medical Center, Joint Base San Antonio (JBSA) Fort Sam Houston, Texas.
Pulmonary/Critical Care Service, Wilford Hall Ambulatory Surgery Center, Lackland Air Force Base, Texas.
Respir Care. 2019 Jul;64(7):786-792. doi: 10.4187/respcare.06419. Epub 2019 Mar 19.
Obstructive lung disease is diagnosed by a decreased ratio of FEV to the vital capacity (VC). Although the most commonly used VC is FVC, American Thoracic Society guidelines suggest alternative VCs, for example, slow VC (SVC), may offer a more-accurate evaluation of breathing capacity. There is recent evidence that using only FEV/FVC underrecognizes obstruction in subjects at high risk and who are symptomatic. Previous studies have indicated that healthy individuals show a minimum difference between FVC and SVC; however, testing of individuals with asthma and who are symptomatic indicates that SVC can be markedly larger than FVC.
To evaluate the differences among SVC, FVC, and SVC-based measurements in the diagnosis of symptomatic obstructive lung disease.
A retrospective analysis was performed of spirometry and plethysmography measurements from studies conducted between 2011 to 2015. We established a pulmonary function database that incorporated predictive equations from the National Health and Nutrition Examination Survey III (NHANES III). The SVC to FVC difference was calculated. FEV/SVC was compared with FEV/FVC by using NHANES III lower limit of normal values.
A total of 2,710 studies with 2,244 subjects were reviewed. Spirometric obstruction, as defined by NHANES III, was identified in 26.1% of the studies (707/2,710). The mean (± SD) difference between SVC and FVC was 375.0 ± 623.0 mL and 258.8 ± 532.5 mL in those with and those without obstruction, respectively. Subgroup and multivariate analysis demonstrated age, body mass index, and FEV associated contributions to the difference between SVC and FVC. By using FEV/SVC, the prevalence of obstruction increased from 26.1 to 45.0% (1,219/2,710) and identified 566 additional studies of subjects with obstruction. Fifty-four percent of the subjects with newly-identified obstructive lung disease (305/566) had smoking histories, and 67.4% (345/512) received medications for obstructive lung disease.
The isolated use of FVC-based diagnostic algorithms did not recognize individuals with symptomatic obstructive lung disease. Recognizing the difference between SVC and FVC measurements in subjects will improve testing and diagnosis of obstructive lung disease.
阻塞性肺疾病通过 FEV 与肺活量（VC）的比值降低来诊断。虽然最常用的 VC 是 FVC，但美国胸科学会指南建议使用其他 VC，例如，缓慢 VC（SVC），可能更准确地评估呼吸能力。最近有证据表明，在高风险和有症状的人群中，仅使用 FEV/FVC 会导致对阻塞的识别不足。先前的研究表明，健康个体的 FVC 和 SVC 之间存在最小差异；然而，对哮喘和有症状的个体进行的测试表明，SVC 可能明显大于 FVC。
评估 SVC、FVC 和基于 SVC 的测量在诊断有症状的阻塞性肺疾病中的差异。
对 2011 年至 2015 年进行的研究中的肺活量计和体积描记法测量值进行了回顾性分析。我们建立了一个肺功能数据库，其中包含来自国家健康和营养检查调查 III（NHANES III）的预测方程。计算了 SVC 与 FVC 的差值。使用 NHANES III 下限正常值比较了 FEV/SVC 与 FEV/FVC。
共回顾了 2,710 项研究，其中包括 2,244 名受试者。根据 NHANES III，26.1%（707/2,710）的研究中发现了肺功能阻塞。无阻塞的研究中 SVC 和 FVC 的平均值（±SD）差异分别为 375.0±623.0 mL 和 258.8±532.5 mL。亚组和多变量分析表明，年龄、体重指数和 FEV 对 SVC 和 FVC 之间的差异有贡献。通过使用 FEV/SVC，阻塞的患病率从 26.1%增加到 45.0%（1,219/2,710），并确定了 566 项有阻塞的受试者的额外研究。新诊断为阻塞性肺疾病的受试者中有 54%（305/566）有吸烟史，67.4%（345/512）接受了阻塞性肺疾病药物治疗。
单独使用基于 FVC 的诊断算法并不能识别有症状的阻塞性肺疾病患者。在有症状的个体中识别 SVC 和 FVC 测量值之间的差异将改善阻塞性肺疾病的检测和诊断。
