An Investigation Into the Pressure and Airflow/Volume Changes Which Accompany Partial Closure of the Larynx During Expiration in Patients With COPD and the Effect of Applying a Positive End Expired Pressure by Facemask on These Parameters
试验速览
- 阶段
- 不适用
- 入组人数
- 30
- 试验地点
- 1
- 主要终点
- We will measure glottic aperture and compare glottic aperture observed with different levels of applied EPAP (expiratory positive airway pressure)in the erect and supine positions
研究概览
简要总结
In this study the investigators aim to investigate the extent to which in patients with chronic obstructive pulmonary disease narrowing of the vocal cords causes a positive pressure within the airways thus improving airflow and lung function. This information will be captured in the upright and lying down positions and an estimate of the magnitude of the effect will be formed by offsetting the pressure by asking the patients to breathe using a commercially available device used to treat sleep apnoea called a CPAP machine. This is an observational study in which the observation of laryngeal aperture, and mouth and oesophageal pressure at differing levels of applied CPAP will be recorded for analysis in patients with COPD and in normal subjects without COPD. All will have the same measurements, observations, and interventions to allow us to observe and measure pressure, laryngeal aperture, and airflow .
详细描述
In patients with chronic obstructive pulmonary disease (COPD) flow limitation inherent to the condition causes gas trapping and consequently over-inflation of the lung termed hyperinflation which worsens on exercise. Expiratory airflow can be maximized if the intrinsic positive pressure in the lung (Positive end expired pressure,PEEP) is offset by externally applied pressure (Expiratory positive airway pressure,EPAP) and it has been noted that patients with COPD do this by pursed lips breathing on expiration. The applicants have shown in a preliminary study that patients with COPD also close their vocal cords during expiration and is hypothesised that the function of the glottic narrowing was to provide an external positive expiratory pressure thus reducing flow limitation.
Relatively few data exist on laryngeal airflow in humans. One therapy that is increasingly used in the treatment of acute and chronic respiratory failure is non invasive pressure ventilation. Devices used for this oscillate between a high Inspiratory positive airway pressure (IPAP) and a lower Expiratory positive airway pressure (EPAP) but there remains uncertainty as how best to titrate the EPAP. We speculate that the optimum EPAP would be one to most reduce glottic narrowing on the basis that this would optimise expiratory flow and reduce the drive to glottic narrowing. The aim of this study is to test this hypothesis and to identify the range of external applied EPAP which minimises glottic narrowing in COPD patients in the erect and supine positions.
Technical advances with the use of continuous laryngoscopic examination (CLE) now provide a feasible and safe method to directly observe laryngeal movement from a fixed position. We aim to measure intra-thoracic pressure using an oesophageal balloon during respiration and to relate this to the CLE movement of the larynx.
At the same time we will be measuring airflow and volume with a pneumotachograph. This will allow us to identify the effect of glottic narrowing on intra-thoracic pressure and to see if the glottic narrowing does lead to an increased positive end expired pressure in the chest ( positive end expired pressure intrathoracic,PEEPi) and the extent to which it can be offset using EPAP delivered by a positive pressure machine (continuous positive airways pressure,CPAP).
The design of this study is a one visit physiological study which is an observational study with no blinding of investigator or participants.
研究设计
- 研究类型
- Observational
- 观察模型
- Case Control
- 时间视角
- Prospective
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
- 是
入选标准
- •patients with COPD
- •Gold stage 11 as severity of disease
- •male and female
- •at least 1 pack/day of cigarettes for >10 years
- •normal subjects
- •no evidence of Chronic Obstructive pulmonary disease (COPD) on spirometry
- •< 1 pack of cigarettes/day for 10 years
- •male and female
排除标准
- •an inability to comprehend what is proposed or travel to appointments
- •restrictive lung pathology as assessed by history and lung function testing
- •active infection
- •evidence of cardiac disease
- •inability to tolerate any of the following
- •the fibre-optic laryngoscope
- •the passing and retention of the oesophageal balloon
- •the wearing of a face mask
- •the application of a low level of positive pressure to the face mask and mouth ( CPAP, EPAP)
- •those who are receiving a trial drug as part of another study at the time of study
- •pregnancy
结局指标
主要结局
We will measure glottic aperture and compare glottic aperture observed with different levels of applied EPAP (expiratory positive airway pressure)in the erect and supine positions
时间窗: 2 years
we will measure glottic aperture and compare glottic aperture observed with different levels of applied EPAP on glottic opening in the erect and supine positions
次要结局
- We will measure glottic aperture and and functional lung volumes ( inspiratory capacity and functional residual capacity) in the erect and supine positions at different levels of EPAP.(2 years)
- We will determine the effect on PEEPi of applied EPAP in the erect and supine positions(2 years)