Qualitative Descriptors of Dyspnea During Exercise in Cystic Fibrosis
试验速览
- 阶段
- 不适用
- 状态
- 已完成
- 入组人数
- 50
- 试验地点
- 1
- 主要终点
- To determine if dyspnea is qualitatively and quantitatively different in patients with cystic fibrosis compared with age and sex-matched healthy controls during exercise
研究概览
简要总结
Shortness of breath (dyspnea) during exercise is a major source of distress and is a commonly reported symptom in patients with cystic fibrosis (CF). Due to the investigators' poor understanding of how dyspnea develops, there are no treatments that consistently reduce dyspnea in this population. The investigators aim to acquire a more comprehensive understanding of the physiological mechanisms of exertional dyspnea in CF patients. This study will likely identify an important physiological mechanism of dyspnea in CF and may contribute to the development and use of effective treatments to reduce dyspnea in this population.
The central hypothesis is that the impaired tidal volume (VT) response during exercise in CF, in the setting of increased ventilatory demand will give rise to different qualitative descriptions of exertional dyspnea compared with healthy age and sex-matched controls. Specifically, CF patients will select "increased work and effort" as their dominant descriptor of dyspnea up to the VT inflection/plateau. Beyond this point, CF patient's dominant descriptor will become "unsatisfied inspiration." In contrast, healthy control participants will report "increased work and effort" throughout all phases of exercise and will not report "unsatisfied inspiration", even after the VT inflection/plateau.
详细描述
The purpose of this study is to determine if sensations of breathlessness (dyspnea) are qualitatively and quantitatively different in patients with cystic fibrosis (CF) compared to age and sex-matched healthy controls during exercise, and to determine if these differences can be explained by differences in the ventilatory response to exercise.
Understanding the progression of dyspnea during exercise will enable the investigators to better understand the pathophysiological mechanisms of this debilitating symptom in patients with CF. A more comprehensive understanding of the mechanisms underlying exertional dyspnea may ultimately lead to new therapeutic interventions (pharmacologic and non pharmacologic) that would positively impact exercise limitations in CF. A healthy control group will enable investigators to better identify the "normal" physiological and perceptual responses to exercise so that direct comparisons to patients with CF may be drawn.
Experimental Overview: Participants with CF and healthy control participants will report to the exercise laboratory for one visit. Informed consent, medical history screening, evaluation of chronic activity-related dyspnea and anthropometric measurements will firstly be obtained. Subjects will then be familiarized with the cycle ergometer, breathing apparatus and symptom scales. This will be followed by simple spirometry testing. After which participants will rest prior to a symptom limited incremental cycle exercise test. Detailed physiological and sensory measurements will be obtained during the familiarization and exercise test sessions. Data from the exercise test will address our hypotheses.
Study Participants: The study will include 40 participants in total. Of the 40 participants, 20 will be patients with CF and 20 will be healthy age and sex-matched controls.
Exercise Protocol: A symptom-limited incremental exercise test will be performed using an electronically braked cycle ergometer according to recommended guidelines. The test will consist of steady-state rest for 10 minutes, a 1 minute warm-up at 0 watts, and 20 watt stepwise increases in work rate every 2 minutes until symptom-limitation.
研究设计
- 研究类型
- Observational
- 观察模型
- Case Control
入排标准
- 年龄范围
- 19 Years 至 50 Years（Adult）
- 性别
- All
- 接受健康志愿者
- 是
入选标准
- •CF patients (confirmed based on abnormal sweat chloride testing and/or CF Transmembrane Conductance Regulator (CFTR) genotyping)
- •Between the ages of 19 to 50 (inclusive)
- •Stable clinical status (CF: no changes in therapy in the past 4 weeks)
- •Forced Expiratory Volume in 1 second (FEV1.0) >40% predicted
- •Body mass index greater than 18 or less than 30
- •Currently non-smoking or a past smoking history of less than 20 pack-years
- •Able to read and understand English
排除标准
- •A disease other than CF that could contribute to dyspnea or exercise limitation
- •Having either of the chronic infections Mycobacterium abscessus or Burkholderia cepacia complex
- •Contraindications to clinical exercise testing
- •Use of supplemental oxygen or desaturation less than 85% with exercise
- •Diagnosis of pneumothorax in the past 4 weeks
结局指标
主要结局
To determine if dyspnea is qualitatively and quantitatively different in patients with cystic fibrosis compared with age and sex-matched healthy controls during exercise
时间窗: Parameters will be measured during the 1 visit.
Included will be 20 patients with cystic fibrosis (CF) who have no other pulmonary or extra-pulmonary limitation to exercise, as well as 20 healthy age and sex-matched control participants. All participants (CF and control) will perform an incremental symptom-limited cardio-pulmonary exercise test while detailed cardio-respiratory responses, dyspnea responses, muscle oxygenation and muscle hemodynamic data are measured.
次要结局
- To determine if the dyspnea responses can be explained by differences in the ventilatory response to exercise.(Parameters will be measured during the 1 visit.)