Frisk Bente, Hardie Jon A, Espehaug Birgitte, Strand Liv I, Moe-Nilssen Rolf, Eagan Tomas M L, Bakke Per S, Thorsen Einar
Centre for Evidence-Based Practice, Bergen University College, Bergen, Norway.
Department of Clinical Science, University of Bergen, Bergen, Norway.
BMC Pulm Med. 2015 Aug 19;15:93. doi: 10.1186/s12890-015-0095-y.
Activities of daily living in patients with chronic obstructive pulmonary disease (COPD) are limited by exertional dyspnea and reduced exercise capacity. The aims of the study were to examine longitudinal changes in peak oxygen uptake (V̇O2peak), peak minute ventilation (V̇Epeak) and breathing pattern over four years in a group of COPD patients, and to examine potential explanatory variables of change.
This longitudinal study included 63 COPD patients, aged 44-75 years, with a mean forced expiratory volume in one second (FEV1) at baseline of 51 % of predicted (SD = 14). The patients performed two cardiopulmonary exercise tests (CPETs) on treadmill 4.5 years apart. The relationship between changes in V̇O2peak and V̇Epeak and possible explanatory variables, including dynamic lung volumes and inspiratory capacity (IC), were analysed by multivariate linear regression analysis. The breathing pattern in terms of the relationship between minute ventilation (V̇E) and tidal volume (VT) was described by a quadratic equation, VT = a + b∙V̇E + c∙V̇E (2), for each test. The VTmax was calculated from the individual quadratic relationships, and was the point where the first derivative of the quadratic equation was zero. The mean changes in the curve parameters (CPET2 minus CPET1) and VTmax were analysed by bivariate and multivariate linear regression analyses with age, sex, height, changes in weight, lung function, IC and inspiratory reserve volume as possible explanatory variables.
Significant reductions in V̇O2peak (p < 0.001) and V̇Epeak (p < 0.001) were related to a decrease in resting IC and in FEV1. Persistent smoking contributed to the reduction in V̇O2peak. The breathing pattern changed towards a lower VT at a given V̇E and was related to the reduction in FEV1.
Increasing static hyperinflation and increasing airway obstruction were related to a reduction in exercise capacity. The breathing pattern changed towards more shallow breathing, and was related to increasing airway obstruction.
慢性阻塞性肺疾病（COPD）患者的日常生活活动受到运动性呼吸困难和运动能力下降的限制。本研究的目的是在一组COPD患者中检查四年间峰值摄氧量（V̇O2peak）、峰值分钟通气量（V̇Epeak）和呼吸模式的纵向变化，并检查变化的潜在解释变量。
这项纵向研究纳入了63例年龄在44 - 75岁之间的COPD患者，基线时一秒用力呼气容积（FEV1）平均为预测值的51%（标准差 = 14）。患者在4.5年的间隔时间内进行了两次跑步机心肺运动试验（CPET）。通过多变量线性回归分析，分析V̇O2peak和V̇Epeak的变化与包括动态肺容量和吸气容量（IC）在内的可能解释变量之间的关系。每次试验中，用二次方程VT = a + b∙V̇E + c∙V̇E²来描述分钟通气量（V̇E）与潮气量（VT）之间关系的呼吸模式。从个体二次关系中计算出VTmax，它是二次方程一阶导数为零的点。以年龄、性别、身高、体重变化、肺功能、IC和吸气储备量作为可能的解释变量，通过双变量和多变量线性回归分析，分析曲线参数（CPET2减去CPET1）和VTmax的平均变化。
V̇O2peak（p < 0.001）和V̇Epeak（p < 0.001）的显著降低与静息IC和FEV1的下降有关。持续吸烟导致V̇O2peak降低。在给定的V̇E时，呼吸模式向较低的VT转变，并且与FEV1的降低有关。
静态肺过度充气增加和气道阻塞加重与运动能力降低有关。呼吸模式向更浅的呼吸转变，并且与气道阻塞加重有关。
