Division of Laboratory and Transfusion Medicine, Hokkaido University Hospital, Sapporo, Hokkaido, Japan.
Department of Respiratory Medicine, Faculty of Medicine and Graduate School of Medicine, Hokkaido University, Sapporo, Hokkaido, Japan.
Int J Chron Obstruct Pulmon Dis. 2021 Feb 24;16:415-422. doi: 10.2147/COPD.S285086. eCollection 2021.
Generally, the maximal expiratory flow-volume (MEFV) curve must be measured for the diagnosis and staging of chronic obstructive pulmonary disease (COPD). As this test is effort dependent, international guidelines recommend that three acceptable trials are required for each test. However, no study has examined the magnitude and factors for the variability in parameters among three acceptable trials.
We evaluated the intra-individual variations in several parameters among three acceptable MEFV curves obtained at one-time point in patients with COPD (n = 28, stage 1; n = 36, stage 2; n = 21, stages 3-4). Next, the factors for such variations were examined using forced expiratory volume in 1 second (FEV) and forced vital capacity (FVC).
The averages of coefficient of variation (CV) for FEV and FVC were 2.0% (range: 1.0-3.0%) and 1.6% (0.9-2.2%), respectively. Both parameters were significantly better than peak expiratory flow rate, forced expiratory flow at 50% of expired FVC, and forced expiratory flow at 75% of expired FVC (CVs: 5.0-6.9%). A higher spirometric stage was significantly associated with higher CVs for FVC and FEV and older age was significantly correlated with a higher variation in FEV alone. Furthermore, a significantly inverse association was observed between emphysema severity, and the CVs for FEV, but not that for FVC, regardless of spirometric stage.
Both FVC and FEV are highly reproducible; nevertheless, older age, lower FEV at baseline, and non-emphysema phenotype are factors for a higher variability in FEV in patients with COPD.
通常情况下，为了诊断和分期慢性阻塞性肺疾病（COPD），必须测量最大呼气流量容积（MEFV）曲线。由于该测试依赖于努力程度，国际指南建议每个测试需要进行三次可接受的试验。然而，尚无研究探讨三次可接受的试验中参数的变异性幅度及其影响因素。
我们评估了 28 例 COPD 患者（第 1 期 n = 28；第 2 期 n = 36；第 3-4 期 n = 21）单次检测获得的三次可接受 MEFV 曲线中多个参数的个体内差异。接下来，使用 1 秒用力呼气量（FEV）和用力肺活量（FVC）检查了这些差异的影响因素。
FEV 和 FVC 的变异系数（CV）平均值分别为 2.0%（范围：1.0-3.0%）和 1.6%（0.9-2.2%）。这两个参数均明显优于呼气峰流量、50%肺活量时的用力呼气流量和 75%肺活量时的用力呼气流量（CV：5.0-6.9%）。肺功能分期越高，FVC 和 FEV 的 CV 越高，年龄越大，仅 FEV 的变异越大。此外，无论肺功能分期如何，均观察到肺气肿严重程度与 FEV 的 CV 呈显著负相关，而与 FVC 的 CV 无关。
FVC 和 FEV 的重复性均较高；然而，在 COPD 患者中，年龄较大、基线时 FEV 较低以及非肺气肿表型是 FEV 变异性较大的影响因素。
