Effect of CPAP on Respiratory Load and Lung Volume in Stable COPD
试验速览
- 阶段
- 不适用
- 状态
- 已完成
- 发起方
- 入组人数
- 19
- 试验地点
- 1
- 主要终点
- Inspiratory work
研究概览
简要总结
Both intrinsic positive end expiratory pressure (PEEPi) and dynamic hyperinflation are considered as inspiratory loads which increase work of breathing in patients with COPD. The application of extrinsic positive end expiratory pressure (PEEPe) supplied by CPAP has been claimed to reduce inspiratory load based on change in esophageal pressure which could be significantly affected by change in lung volume and airflow. The investigator hypothesized that CPAP could increase respiratory load because it increases lung volume.
详细描述
Objective
To assess the effect of CPAP on respiratory load and lung volume in stable COPD. Methods: Patients with COPD were recruited to breath under the atmosphere pressure and different levels of CPAP (4, 6, 8 and 10 cm H2O). Diaphragm EMG, esophageal pressure (Pes) and transdiaphragmatic pressure (Pdi) were recorded using balloon esophageal electrode catheter (Yinghui, Guangzhou, China). End inspiratory lung volume (EILV) was measured directly from a pneumotachograph combined with a three way valve under the different CPAP levels. Sensation of breathing difficulty was also assessed. In an additional study, the effect of airflow on pressure was investigated by a physical mode.
研究设计
- 研究类型
- Interventional
- 分配方式
- Na
- 干预模型
- Single Group
- 主要目的
- Treatment
- 盲法
- None
入排标准
- 年龄范围
- 40 Years 至 80 Years（Adult, Older Adult）
- 性别
- All
- 接受健康志愿者
- 否
入选标准
- •Willing to participate after informed consent
- •Males and females, any race and aged 40-80 years
- •GOLD II-IV COPD (post-bronchodilator FEV1 < 80 % of the predicted normal, and a post-bronchodilator FEV1/FVC < 0.70)
排除标准
- •Patients recovering from acute exacerbation less than 4 weeks.
- •Patients with concomitant pulmonary disease (e.g. lung fibrosis, interstitial lung disorder).
结局指标
主要结局
Inspiratory work
时间窗: Around 5 minutes signals under the atmosphere pressure and different levels of CPAP (4, 6, 8 and 10 cm H2O) were recorded.
the pressure-time product of the respiratory muscles (PTPes/min) and of the diaphragm (PTPdi/min) were calculated under the Pes and Pdi versus time curve and expressed per minute.
Diaphragm EMG
时间窗: Around 5 minutes signals under the atmosphere pressure and different levels of CPAP (4, 6, 8 and 10 cm H2O) were recorded.
assessment of the electrical activity of the diaphragm (EMG-di)
Sensation of breathing effort
时间窗: 5 minutes after each CPAP level (0, 4, 6, 8 and 10 cm H2O)
Using questionnaire to assess the sensation of breathing effort. Sensation of breath effort of CPAP use was divided into three types corresponding to -1, 0, 1 score respectively, 0 refers to the same sensation as the feeling of breathing at the atmosphere without CPAP; 1 refers to the more difficult sensation to breath at the CPAP condition than at the atmosphere.; -1 refers to the easier sensation to breath at the CPAP condition than at the atmosphere.
Lung volume
时间窗: 1-3 minutes after each CPAP level (0, 4, 6, 8 and 10 cm H2O)
measurement of end inspiratory lung volume (EILV)
Inspiratory pressure
时间窗: Around 5 minutes signals under the atmosphere pressure and different levels of CPAP (4, 6, 8 and 10 cm H2O) were recorded.
assessment of esophageal pressure and transdiaphragmatic pressure by caculating tidal variations in Pes (∆Pes) and Pdi (∆Pdi) relatived to initiation of effort.
Intrinsic positive end expiratory pressure (PEEPi)
时间窗: Around 5 minutes signals under the atmosphere pressure and different levels of CPAP (4, 6, 8 and 10 cm H2O) were recorded.
PEEPi was calculated from the negative deflection in Pes from the onset of inspiratory effort to the point of zero flow during spontaneous breathing.
次要结局
- Respiratory rate (RR)(Around 5 minutes signals under the atmosphere pressure and different levels of CPAP (4, 6, 8 and 10 cm H2O) were recorded.)
- Tidal volume (Vt)(Around 5 minutes signals under the atmosphere pressure and different levels of CPAP (4, 6, 8 and 10 cm H2O) were recorded.)
- Peak inspiratory flow rate(Around 5 minutes signals under the atmosphere pressure and different levels of CPAP (4, 6, 8 and 10 cm H2O) were recorded.)
- Expiratory pressure(Around 5 minutes signals under the atmosphere pressure and different levels of CPAP (4, 6, 8 and 10 cm H2O) were recorded.)
- Minute ventilation (VE)(Around 5 minutes signals under the atmosphere pressure and different levels of CPAP (4, 6, 8 and 10 cm H2O) were recorded.)
- Expiratory muscle EMG(Around 5 minutes signals under the atmosphere pressure and different levels of CPAP (4, 6, 8 and 10 cm H2O) were recorded.)
研究者
Yuan-Ming Luo
Professor
State Key Laboratory of Respiratory Disease