持续性哮喘患者运动期间主诉呼吸困难症状的变化
2007/03/12
Donald A. Mahler等假设在运动心肺功能试验时，高血碳酸可以增加而高血氧可以降低作功－呼吸困难曲线的斜率。作者入选了30例持续性哮喘患者（男女各15例，FEV1/FVC，57±10%），共进行4次随访，第1次随访时，训练患者掌握运动试验测定方法和步骤，运动试验开始前，所有患者吸入2喷沙丁胺醇，以使试验前肺功能标准化。随访2至随访4，患者在试验时随机吸入一种混合气体，由此造成高血碳酸（吸入5%CO2），高血氧（40%O2）和对照组（吸入空气）三种实验条件。
结果表明在三种实验条件下，运动前和运动后，肺功能无变化。高血碳酸者最大通气量增加，最大氧耗量及作功减少，作功－呼吸困难曲线斜率增加，25例患者（83%）因主诉呼吸困难终止试验。高血氧者最大通气量减少，最大作功和作功－呼吸困难曲线斜率无变化，16例患者（53%）因主诉腿部不适终止试验。
由此作者认为，吸入5% CO2可以改变哮喘患者在运动试验期间的生理反应以及作功－呼吸困难曲线的斜率，而高血氧的反应则不一致，在运动负荷递增连续测定时，呼吸困难主诉适用于高血碳酸者，而不适用于高血氧者。
（赵海涛 沈阳军区总医院呼吸内科 110016 摘译）
(CHEST 2007,131:195-200)Responsiveness of Patient-Reported Breathlessness During Exercise in Persistent Asthma*
Donald A. Mahler, MD, FCCP; Laurie A. Waterman, BS; Joseph Ward, RCPT and John C. Baird, PhD
Abstract
Background: The purpose of the study was to examine the responsiveness of a computerized system whereby the patient reports spontaneously any change in the intensity of breathlessness during exercise. The hypotheses were that hypercapnia would increase and hyperoxia would decrease the slope of power production-breathlessness ratings compared with a control condition during cycle ergometry.
Methods: Thirty adult subjects (15 women and 15 men) with persistent asthma (mean [± SD] FEV1/FVC ratio, 57 ± 10%) completed an initial familiarization visit and three study visits. All subjects inhaled two puffs of albuterol (180 μg) in order to standardize lung function prior to exercise. At visits 2 to 4, subjects breathed one of the three gas mixtures administered in a random order while performing a ramp exercise test. The experimental conditions were as follows: hypercapnia (5% carbon dioxide); hyperoxia (40% oxygen); and control (room air).
Results: Lung function was the same before and after exercise with the three experimental conditions. With hypercapnia, peak ventilation was increased, peak oxygen consumption, and power production were reduced, the slope of power-breathlessness was increased, and 25 patients (83%) reported breathlessness as the limiting symptom. With hyperoxia, peak ventilation was decreased, peak power production and the slope of power-breathlessness were unchanged, and 16 patients (53%) reported leg discomfort as the limiting symptom.
Conclusions: Breathing 5% carbon dioxide altered physiologic responses and the slope of power production-breathlessness during exercise. The responses to hyperoxia were inconsistent. The continuous method for patient-reported breathlessness was responsive to hypercapnia, but not to hyperoxia, during incremental exercise.
Key Words: adults with asthma·computer ratings of breathlessness·exercise testing·hypercapnia·hyperoxia
上一篇：
哮喘急性发作患者的肺功能测定结果
下一篇：
吸烟哮喘患者对糖皮质激素的全身敏感性
