Puente-Maestu Luis, García de Pedro Julia, Martínez-Abad Yolanda, Ruíz de Oña José Maria, Llorente Daniel, Cubillo José Manuel
Hospital General Universitario Gregorio Marañón, Servicio de Neumología, c/o Doctor Ezquerdo 46, 28007 Madrid, Spain.
Chest. 2005 Aug;128(2):651-6. doi: 10.1378/chest.128.2.651.
We undertook the present study to investigate the perception of dyspnea (with respect to changes in end-inspiratory and end-expiratory lung volumes), during four different levels of high-intensity constant work rate exercise (CWRE) in patients with severe COPD.
Crossover descriptive study with consecutively recruited subjects.
Tertiary university hospital.
Twenty-seven subjects with severe COPD (mean [+/- SD] age, 65 +/- 5 years of age; mean FEV1, 43 +/- 8% predicted; and mean inspiratory capacity [IC]; 74 +/- 14% predicted).
Subjects randomly performed four high-intensity CWRE tests (conducted at 65%, 75%, 85%, and 95% of their symptom-limited peak work rate). Dyspnea, leg fatigue, and IC were determined every 2 min during exercise with breath-by-breath gas exchange and ventilatory measurements. There was a good correlation between the resting IC percent predicted and the oxygen uptake (V(O2)) peak (r = 0.64 to 0.69 between the IC percent predicted and V(O2) peak at the four work rates). There were significant differences (p < 0.01) in mean respiratory rate (33 +/- 6, 35 +/- 6, 37 +/- 6, and 38 +/- 6 min), peak dyspnea score (5.9 +/- 1.3, 6.3 +/- 1.4, 6.8 +/- 1.2, and 6.9 +/- 1.6), minute ventilation (45.0 +/- 8.7, 43.8 +/- 7.7, 43.1 +/- 8.7, and 42.8 +/- 8.0 L/min), leg fatigue (4.8 +/- 1.3, 5.1 +/- 1.3, 5.7 +/- 1.4, and 5.8 +/- 1.4), and end-tidal carbon dioxide partial pressure (4.41 +/- 0.36, 4.53 +/- 0.33, 4.66 +/- 0.31, and 4.76 +/- 0.24 kPa), respectively, for tests conducted at 65%, 75%, 85%, and 95% of their symptom-limited peak work rate, and in mean end-expiratory lung volume ([EELV] 4.55 +/- 0.44, 4.69 +/- 0.43, and 4.79 +/- 0.43 L), respectively, for tests conducted at 65%, 75%, and 85% of their symptom-limited peak work rate. In multivariable analysis, the factors that were independently correlated with dyspnea (p < 0.05) were EELV, peak inspiratory flow, and leg fatigue/discomfort.
In COPD subjects with flow limitation at rest, the perception of dyspnea increased nonlinearly with the magnitude of high-intensity CWRE in association with a faster respiratory pattern and an increase in EELV. At the highest work rates, it appeared that a reduction in tidal volume and ventilation peak may have limited the tolerance to exercise.
我们开展本研究旨在调查重度慢性阻塞性肺疾病（COPD）患者在四种不同强度的高强度恒定工作率运动（CWRE）期间对呼吸困难的感知（相对于吸气末和呼气末肺容积的变化）。
对连续招募的受试者进行交叉描述性研究。
三级大学医院。
27名重度COPD患者（平均[±标准差]年龄为65±5岁；平均第1秒用力呼气容积[FEV1]为预计值的43±8%；平均吸气容量[IC]为预计值的74±14%）。
受试者随机进行四项高强度CWRE测试（分别在其症状限制峰值工作率的65%、75%、85%和95%下进行）。在运动过程中，每隔2分钟通过逐次呼吸气体交换和通气测量来确定呼吸困难、腿部疲劳和IC。静息时预计IC百分比与摄氧量（V̇O₂）峰值之间存在良好的相关性（在四种工作率下，预计IC百分比与V̇O₂峰值之间的r值为0.64至0.69）。分别在其症状限制峰值工作率的65%、75%、85%和95%下进行测试时，平均呼吸频率（33±6、35±6、37±6和38±6次/分钟）、峰值呼吸困难评分（5.9±1.3、6.3±1.4、6.8±1.2和6.9±1.6）、分钟通气量（45.0±8.7、43.8±7.7、43.1±8.7和42.8±8.0升/分钟）、腿部疲劳（4.8±1.3、5.1±1.3、5.7±1.4和5.8±1.4）以及呼气末二氧化碳分压（4.41±0.36、4.53±0.33、4.66±0.31和4.76±0.24千帕）存在显著差异（p<0.01）；分别在其症状限制峰值工作率的65%、75%和85%下进行测试时，平均呼气末肺容积（[EELV]分别为4.55±0.44、4.69±0.43和4.79±0.43升）存在显著差异。在多变量分析中，与呼吸困难独立相关（p<0.05）的因素为EELV、峰值吸气流量以及腿部疲劳/不适。
在静息时存在气流受限的COPD受试者中，呼吸困难的感知随着高强度CWRE强度的增加而非线性增加，同时呼吸模式加快且EELV增加。在最高工作率时，似乎潮气量和通气峰值的降低可能限制了运动耐力。
