Intrinsic PEEP and Laryngeal Aperture in COPD

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 .

Conditions

• Chronic Obstructive Pulmonary Disease

Interventions

PROCEDURE

Oesophageal balloon to measure intra-thoracic pressure

An oesophageal balloon will be inserted via a nostril after instillation of local anaesthetic and swallowed until the tip is in the lower third of the oesophagus. This will allow the intrathoracic pressure to be monitored via a pressure sensor attached to the oesophageal balloon catheter and placed next to the subject. This will allow us to observe the changes in oesophageal pressure during quiet breathing under a variety of applied positive pressure conditions.

PROCEDURE

Fibre-optic laryngoscopy

A fibre-optic laryngoscope will be inserted through the opposite nostril to that used for the oesophageal balloon and placed with its tip abve the larynx where the laryngeal movement can be observed This will allow us to observe the changes in laryngeal aperture under a variety of applied positive pressure conditions.

OTHER

standard lung function tests

These will be carried out in any subject who has not had lung function testing in the previous 6 weeks and will be carried out by a lung function physiologist from the institution in accordance with standard procedures for lung function testing

PROCEDURE

face mask CPAP

The subjects will wear a facemask with apertures for the oesophageal balloon and fibre-optic devices to cover the mouth and nose. airflow and volume will be recorded with a pneumotachograph and there will be tubing to connect to a positive pressure source (CPAP) to allow mouth pressures to be altered between 0-15cm H20.( 1cm H20 is the pressure produced by a column of water of 1centimetre in depth)

PROCEDURE

variation of mouth pressure with CPAP

Once the other procedures are completed the subject will have his mouth pressure varied via application of positive pressure via a commercial CPAP device as used for treatment of obstructive sleep apnoea. The pressure will be varied randomly between 0-15cm H2O (water)for periods of 5 minutes both sitting and lying. Oesophageal balloon recording of intra-thoracic pressure and laryngeal movement and mouth airflow and volume will be recorded simultaneously and at the end of each 5 minute period the subject will be requested to take as big a breath in as possible to allow measurement of functional residual capacity and inspiratory capacity. This will allow us to observe the effect of changing mouth pressure with CPAP on laryngeal aperture and oesophageal pressures and airflow.

OTHER

facemask pneumotachograph

The facemask will incorporate a pneumotachograph to allow measurement of airflow and volumes throughout the respiratory cycle. This will allow us to observe the pattern of airflow with varying applied CPAP

Sponsors & Collaborators

• Royal Brompton & Harefield NHS Foundation Trust

  lead OTHER

Principal Investigators

• michael Polkey, PhD · Royal Brompton & Harefield NHS Foundation Trust

Eligibility

Min Age

40 Years

Max Age

80 Years

Sex

ALL

Healthy Volunteers

Yes

Timeline & Regulatory

Start

2016-04-30

Primary Completion

2018-05-31

Completion

2018-05-31

Countries

• United Kingdom

Study Locations