Clinical Trial: Intrinsic PEEP and Laryngeal Aperture in COPD

Study Status: Recruiting
Recruit Status: Recruiting
Study Type: Observational

Official Title: 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 Pr

Brief Summary: 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 .

Detailed Summary:

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 movem
Sponsor: Royal Brompton & Harefield NHS Foundation Trust

Current Primary Outcome: 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 [ Time Frame: 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


Original Primary Outcome: Same as current

Current Secondary Outcome:

  • 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. [ Time Frame: 2 years ]
    We will measure functional lung volumes , inspiratory capacity and functional residual capacity ,and the glottic aperture in the erect and supine positions at different levels of EPAP
  • We will determine the effect on PEEPi of applied EPAP in the erect and supine positions [ Time Frame: 2 years ]
    We will determine the effect on PEEPi of applied EPAP in the erect and supine positions


Original Secondary Outcome: Same as current

Information By: Royal Brompton & Harefield NHS Foundation Trust

Dates:
Date Received: January 27, 2015
Date Started: April 2016
Date Completion: May 2018
Last Updated: April 8, 2016
Last Verified: April 2016