Validation of Structured Light Plethysmography

Not Applicable

Completed

• Conditions: Pulmonary Disease

• Registration Number: NCT02598336
• Lead Sponsor: Pneumacare Ltd

Brief Summary

Measurements of Structured Light Plethysmography (SLP) using a chest wall movement based method will be compared to those obtained by spirometry using a flow based pneumotachograph method. This study will enable validation of SLP in children and adults by allowing direct comparison of simultaneous measurements of breathing sequences using the two measurement techniques.

The investigators will also examine, in a group of normal adults, repeatability of the agreement between the two devices, and whether the agreement is affected by a change in tidal breathing parameters.

Detailed Description

Measurements using the Structured Light Plethysmography method will be compared to those obtained by spirometry using a flow based pneumotachograph.

Spirometry is the gold standard for measuring lung function in both clinical support and research roles. Modern spirometers are high precision, reliable instruments enabling a large numbers of parameters relating to lung volumes and the rate of emptying the lungs during a forced expiration to be measured. The most common and accurate method to measure the patient's forced expiration is via pneumotachograph which measures the flow of air through a mouthpiece and integrates the signal to derive the volume expired.

Structured Light Plethysmography (SLP) system that measures changes of the chest and abdominal wall movement during breathing by modelling the thorax and abdominal surface defined by a projected structured light pattern which enables a grid of virtual parts to be formed, the movement of which is recorded by digital cameras. SLP provides non-contact assessment to provide lung function data utilising structured light technologies and enhanced imaging processing.

In this study direct comparison will be made of measurements recorded simultaneously using the two measuring devices in children and adults.

To examine repeatability of the agreement between tidal breathing parameters measured by two techniques, repeated measurements will be performed in each of a group of normal adult subjects. The investigators will also examine whether the agreement is affected by a change in tidal breathing parameters. To obtain a change in tidal breathing parameters, measurements will be recorded during resting spontaneous breathing and after a period of exercise to elevate Respiratory Rate.

Study Timeline

• Study Start: 2011-01
• Study First Submitted: 2015-11-03
• Study First Submitted QC: 2015-11-03
• Study First Posted: 2015-11-05
• Primary Completion: 2017-01
• Study Completion: 2017-09
• Status Verified: 2018-07
• Last Update Submitted: 2018-07-07
• Last Update Posted: 2018-07-10

Recruitment & Eligibility

• Status: COMPLETED
• Sex: All
• Target Recruitment: 41

Inclusion Criteria

• For the patient group, any patient attending the outpatient department or the Lung Function Laboratory
• For the Healthy Normals group, any adult between 18 and 80 years with no current or previous respiratory condition.

Exclusion Criteria

• A current cold or other viral infection
• chest surgery within 4 weeks
• Haemoptysis of unknown origin the (forced expiratory manoeuvre may aggravate the underlying condition)
• Pneumothorax
• Unstable respiratory or cardiovascular status (forced expiratory manoeuvre may worsen angina or cause changes in blood pressure) or recent myocardial infarction or pulmonary embolus
• Recent eye surgery
• Presence of an acute disease process that might interfere with test performance (e.g. Nausea, vomiting)

Study & Design

• Study Type: INTERVENTIONAL
• Study Design: PARALLEL

Primary Outcome Measures

Name	Time	Method
Forced Vital Capacity (FVC) measured in Litres	5 minutes	The volume of air a person can exhale during a maximal forced breath
Forced Expiratory Volume in one second (FEV1) measured in litres per second	5 minutes	The volume of air a person can exhale in one second during a maximal forced breath
Peak Expiratory Flow (PEF) measured in litres per second	5 minutes	The maximal flow a person can achieve during a maximal forced breath

Secondary Outcome Measures

Name	Time	Method
Respiratory Waveform	5 minutes	Visual comparison of respiratory waveform shape and amplitude produced by pneumotachograph and SLP.
Respiratory Rate (RR) measured in seconds	5 minutes	Tmings derived from the Respiratory Waveforms
Inspiratory Time (tI) measured in seconds	5 minutes	Timings derived from the Respiratory Waveforms
Total breath time (tTot) measured in seconds	5 minutes	Timings derived from the Respiratory Waveforms
Inspiratory/expiratory ratio (tI/tE) expressed as a ratio	5 minutes	Timing ratios derived from the Respiratory Waveforms
The duty cycle (tI/tTot) expressed as a ratio	5 minutes	Timing ratios derived from the Respiratory Waveforms
Expiratory Time (tE) measured in seconds	5 minutes	Timings derived from the Respiratory Waveforms

Trial Locations

Locations (1)

Cambridge University Hospitals Foundation Trust; 🇬🇧 Cambridge, Cambridgeshire, United Kingdom