Cooper P J, Robertson C F, Hudson I L, Phelan P D
Professional Department of Thoracic Medicine Royal Children's Hospital, Melbourne, Australia.
Pediatr Pulmonol. 1990;8(1):16-22. doi: 10.1002/ppul.1950080107.
The aim of this study was to define the within-subject variability for tests of respiratory function in patients with cystic fibrosis (CF) within the day, from day to day and from week to week. Twenty-eight patients with CF (aged 9-19 years) and 23 healthy height matched controls (aged 9-18 years) had measurements made of spirometry, lung volumes, maximal flows at three lung volumes and maximal inspiratory and expiratory pressures at the mouth. Testings were done on nine occasions, three times within a day, on consecutive days at one week intervals. Each individual's variability was summarized both as the within-subject coefficient of variation (WCV) and within-subject standard deviation (WSD). Means of WSD and median WCV are reported for both the patients with CF and normal subjects. The within-subject variability of VC, FEV1, TLC, RV, and RV/TLC was more appropriately assessed by the use of WSD rather than WCV. The WSDs in the CF group were significantly more variable (P less than 0.005) than in the normals for VC and FEV1. WCV best summarized within-subject variation for FEF25-75, FRC, V25, V50max and V75max for which the CF subjects were significantly more variable (P less than 0.005). Individuals' variability was very consistent, therefore assessment of significant change could be made more accurately by predetermining the variability of that individual, rather than using group data. We stress the importance to consider increased variability from day to day and week to week in the interpretation of change in lung function in patients with CF, and provide reference values for accurate interpretation of serial pulmonary function test results.
本研究的目的是确定囊性纤维化（CF）患者呼吸功能测试在日内、日间和周间的个体内变异性。28例CF患者（9 - 19岁）和23例健康的身高匹配对照者（9 - 18岁）进行了肺活量测定、肺容积、三个肺容积处的最大流量以及口腔最大吸气和呼气压力的测量。测试在九个不同时间进行，一天内进行三次，连续三天，间隔一周。每个个体的变异性通过个体内变异系数（WCV）和个体内标准差（WSD）进行总结。报告了CF患者和正常受试者的WSD均值和WCV中位数。对于VC、FEV1、TLC、RV和RV/TLC，使用WSD比WCV更能恰当评估个体内变异性。CF组中VC和FEV1的WSD比正常组显著更具变异性（P小于0.005）。对于FEF25 - 75、FRC、V25、V50max和V75max，WCV最能总结个体内变异，CF受试者在这些指标上的变异性显著更高（P小于0.005）。个体的变异性非常一致，因此通过预先确定个体的变异性而非使用组数据，可以更准确地评估显著变化。我们强调在解释CF患者肺功能变化时考虑日间和周间变异性增加的重要性，并提供参考值以准确解释系列肺功能测试结果。
