Carter Rick, Holiday David B, Stocks James, Grothues Carol, Tiep Brian
University of Texas Health Center, Tyler, TX 75708, USA.
Arch Phys Med Rehabil. 2003 Aug;84(8):1158-64. doi: 10.1016/s0003-9993(03)00047-9.
To develop regression equations for estimating peak oxygen consumption (Vo(2)) for men and women with moderate to severe chronic obstructive pulmonary disease (COPD) from the 6-minute walk test (6MWT).
Multivariate analysis of patient pulmonary function and exercise gas exchange indices to 2 outcomes for the 6MWT (distance ambulated, calculated work [6M(WORK)]).
A university hospital and clinics.
A total of 124 patients (90 men 34 women; age range, 45\N81y), from the community, with moderate to very severe COPD. Forced expiratory volume in 1 second (FEV(1)) ranged from.70 to 2.79L/min, forced vital capacity (FVC) ranged from 1.73 to 5.77L, and FEV(1)/FVC ranged from 24% to 69%. All patients were in stable condition at the time of testing and were on a stable drug regimen.
Not applicable.
Pulmonary function testing was completed according to American Thoracic Society criteria. Cycle ergometry with gas exchange, by using a ramp protocol, was completed. The 6MWT was done in the hospital corridor, with distances recorded after each minute. Work capacity by each method was reduced from the normal predicted.
Peak oxygen uptake (Vo(2)) averaged 1184+/-302mL/min for men and 860+/-256mL/min for women (58%, 68% of predicted, respectively). Ventilatory reserve was limited at an achieved peak ventilation (Ve) of 79.9%+/-19.1% of predicted. Borg scores for dyspnea and leg fatigue were equivalent for each test modality, with leg fatigue being slightly higher for each gender. 6M(WORK) for the 6MWT was the strongest independent predictor of peak Vo(2) (r=.81, P<.0001), whereas that for distance ambulated was correlated at r equal to.54 (P<.0001). This is a 36% improvement in the variance accounted for by the application of 6M(WORK) as the outcome for the 6MWT. Generalized regression modeling was then used to develop equations for the estimation of peak Vo(2) for the 6MWT. Additional variables included in the model were diffusing capacity of lung for carbon dioxide, FVC, maximal inspiratory pressure, weight (in kilograms), and age, with their appropriate interactions. This derived regression model accounted for 79% on the variance for estimation of peak Vo(2) in the patients studied.
Peak Vo(2) can be estimated for men and for women by using the generalized equations presented. The calculation of 6M(WORK) is an improvement over distance ambulated as the 6MWT outcome. These data build on the existing body of knowledge for the 6MWT and extend its application for patients with COPD. Knowledge of the peak Vo(2) can be used for patient assessment, serial monitoring, evaluating disability, and as a common index of function across modalities. The calculation of 6M(WORK) outperformed distance ambulated and is easily converted to other indices of caloric expenditure that are commonly used in the laboratory and clinical settings.
建立回归方程，以便根据6分钟步行试验（6MWT）估算中重度慢性阻塞性肺疾病（COPD）男性和女性的峰值耗氧量（Vo₂）。
对患者肺功能和运动气体交换指标进行多变量分析，以得出6MWT的2个结果（步行距离、计算得出的功[6M(WORK)]）。
一家大学医院及诊所。
共有124名来自社区的中重度COPD患者（90名男性，34名女性；年龄范围45至81岁）。一秒用力呼气容积（FEV₁）为0.70至2.79L/分钟，用力肺活量（FVC）为1.73至5.77L，FEV₁/FVC为24%至69%。所有患者在测试时病情稳定，且药物治疗方案稳定。
不适用。
根据美国胸科学会标准完成肺功能测试。采用斜坡方案完成带气体交换的踏车测力计测试。6MWT在医院走廊进行，每分钟后记录距离。每种方法的工作能力均低于正常预测值。
男性峰值摄氧量（Vo₂）平均为1184±302mL/分钟，女性为860±256mL/分钟（分别为预测值的58%、68%）。在达到的峰值通气量（Ve）为预测值的79.9%±19.1%时，通气储备受限。每种测试方式的呼吸困难和腿部疲劳的Borg评分相当，每种性别的腿部疲劳评分略高。6MWT的6M(WORK)是峰值Vo₂最强的独立预测指标（r = 0.81，P <.0001），而步行距离的相关系数r为0.54（P <.0001）。将6M(WORK)作为6MWT的结果应用，可使解释的方差提高36%。然后使用广义回归模型建立估算6MWT峰值Vo₂的方程。模型中纳入的其他变量包括肺二氧化碳弥散量、FVC、最大吸气压力、体重（千克）和年龄，以及它们的适当交互作用。该推导回归模型在研究患者中占峰值Vo₂估算方差的79%。
使用给出的广义方程可估算男性和女性的峰值Vo₂。计算6M(WORK)作为6MWT的结果比步行距离有所改进。这些数据以6MWT的现有知识为基础，扩展了其在COPD患者中的应用。峰值Vo₂的知识可用于患者评估、连续监测、评估残疾情况，并作为跨模式的通用功能指标。6M(WORK)的计算优于步行距离，且可轻松转换为实验室和临床环境中常用的其他热量消耗指标。
