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Plain English Summary

Background and study aims
Chronic obstructive pulmonary disease (COPD) is the name used to refer to a number of progressive devastating and debilitating lung diseases, which includes chronic bronchitis, emphysema and chronic obstructive airways disease. People that have COPD typically feel breathless after physical activity, have a persistent cough with phlegm and suffer frequently from chest infections. There is no cure for the condition, but making lifestyle changes (such as stopping smoking) and taking medications (inhalers and/or tablets) can alleviate symptoms. This study is being done to collect information that will be used in the development of a new medical device. The new device is intended to help people with chronic obstructive pulmonary disease (COPD) to monitor their condition at home on a daily basis. The device used in this study is called a capnometer. Different types of capnometer have been in use by doctors for many years. Capnometers measure the amount of carbon dioxide in the breath. The device that is used in this study is called the N-Tidal C. It is a small, battery-powered personal device to use indoors either at home, at work or in hospital.

Who can participate?
COPD patients aged at least 18

What does the study involve?
The study fits around the a COPD patient’s normal treatment, tests and medication and there are no changes made to this treatment. At the start of the study each participant is trained in the use of the device and they are asked to use the device to record their normal relaxed breathing, 3 times a day (morning, afternoon and evening) every day for the next six weeks. A reading takes 75 seconds of ordinary breathing through the device. Participants who feel unwell, or have an infection, are asked to take more frequent breath records of up to six times a day if possible – that is twice in the morning, twice in the afternoon and twice in the evening - leaving at least an hour between readings. Standard care clinical assessments are taken at the start of the study, after 2 weeks, 4 weeks and, finally, 6 weeks. The tests for COPD include a check-up by the study doctor or nurse including the usual spirometry and blood gas tests. Each assessment visit takes between 15-20 minutes. Participants are also asked to complete a simple daily diary of how their health and COPD changes and information on the use of the device. Finally, all participants receive a telephone call 2 weeks after their last assessment visit to check how they are and to ask if any of their medicines have changed.

What are the possible benefits and risks of participating?
Participants will not benefit directly from taking part in this study and the device used in the study does not provide any feedback to them. The information the researchers get from this study will help them to develop the device, and to learn more about the treatment and management of COPD. The study researchers do not believe that there are any risks to participants who use the N-Tidal C device in accordance with the instructions for use. An early version of it was tested on people with COPD and they did not report any side effects or difficulties with breathing through the device.

Where is the study run from?
Cambridge University Hospitals NHS Foundation Trust, Addenbrooke's Hospital, Lung Function Unit (UK)

When is the study starting and how long is it expected to run for?
January 2016 to July 2016

Who is funding the study?
The Small Business Research Initiative for Healthcare (UK)

Who is the main contact?
Dr Ravi Mahadeva

Trial website

Contact information



Primary contact

Dr Ravi Mahadeva


Contact details

Consultant Chest Physician
Cambridge University Hospitals NHS Foundation Trust
Cambridge Biomedical Campus
Hills Road
United Kingdom

Additional identifiers

EudraCT number number


Protocol/serial number


Study information

Scientific title

An exploratory, observational clinical evaluation of the CRiL N­-Tidal C data-collector capnometer to collect breathing records in patients with COPD



Study hypothesis

The purpose of this planned investigation is to collect data from patients whose COPD is undergoing change. Such patients are either at risk of an acute exacerbation of COPD, or they have already been hospitalised for treatment of an acute exacerbation. The intention is to correlate capnometric data during this journey with existing measurements (spirometry, blood gas, partial pressure of carbon dioxide [PaCO2], clinical symptoms and clinical assessments). It should then be possible to predict the exhaled CO2 signature of an exacerbation of COPD in normocapnic and hypercapnic patients.
The eventual aim of the N-Tidal C is to facilitate the monitoring and management of patients in the community with moderate to severe COPD. In its final developed form, the N-Tidal C will detect any changes in the patient’s exhaled CO2 capnograph, which would indicate a worsening of their condition and risk of exacerbation. The device would then use a ‘traffic light’ warning system to advise the patient of a change of condition, prompting the patient to seek medical attention. This timely intervention in the community should reduce the number of COPD admissions to hospital.

Ethics approval

NRES Committee Yorkshire & The Humber - Bradford Leeds, 10/09/2015, ref: 15/YH/0369

Study design

Observational longitudinal study

Primary study design


Secondary study design

Longitudinal study

Trial setting


Trial type


Patient information sheet

Not available in web format, please use the contact details to request a patient information sheet


Specialty: Respiratory disorders, Primary sub-specialty: COPD


Patients will be enrolled into one of two cohorts:

1. Stable patients with chronic hypercapnia (raised blood levels of CO2). They will be monitored in the community (community-based case managed group)
2. Hospitalised patients admitted with COPD related respiratory failure. They will be monitored during  recovery in hospital and post discharge (acute admission group)

Patients who give informed consent will be screened for the study. Patients in the case-managed group will be screened at home or in routine clinic visits. Patients in the acute admission group will be screened after admission to hospital as soon as they are well enough to understand the study and to give written informed consent.

The N-Tidal C data-collector capnometer will be explained to the patients and they will be trained how to use it. Case-managed patients will be asked to use the device at home over a period of approximately 6 weeks, 3 times per day (morning, afternoon and evening), or 6 times per day if they feel that they are starting an infection or an exacerbation. Hospitalised patients will also use the device 3 times per day as in-patients and will then continue with the monitoring after discharge from hospital for a total period of 6 weeks. All patients will complete a daily diary record.

Case-managed patients will undergo clinical assessment of COPD during screening at home or in the COPD clinic; in-patients will undergo clinical assessment of COPD following admission and before discharge from hospital. All patients will be assessed a further 3 times: during the second and fourth week in the community, and at the end of the 6-week assessment period. A brief follow-up review will be conducted approximately 8 weeks after the start of capnometer monitoring. At each assessment, capnometry measurements will be taken in addition to routine spirometry, and arterial (in-patients) or capillary (in the community) blood gasses. The trial will not interfere with routine management of the patient’s condition.

Intervention type



Drug names

Primary outcome measure

Changes in exhaled CO2 profiles obtained by the N-Tidal C data-collector capnometer. The reading, which typically takes 60 seconds to collect, will be repeated three times daily, for a period of six weeks.

Secondary outcome measures

No secondary outcome measures

Overall trial start date


Overall trial end date


Reason abandoned (if study stopped)


Participant inclusion criteria

1. Patients of either sex, age 18 years and over, diagnosed with COPD, who have given written, informed consent
2. Patients in the case-managed group will have chronically elevated partial pressure of
carbon dioxide (PaCO2) and will be susceptible to frequent exacerbations of COPD
3. Patients in the acute admission group will have been admitted to hospital via the emergency room for treatment of COPD­related ventilatory failure

Participant type


Age group




Target number of participants

Planned Sample Size: 30; UK Sample Size: 30

Participant exclusion criteria

1. Diagnosis of neuromuscular disorders or kyphoscoliosis
2. Patients who, in the opinion of the investigator are unlikely to comply with the requirements of the study, 
use the device correctly, or keep the diary records

Recruitment start date


Recruitment end date



Countries of recruitment

United Kingdom

Trial participating centre

Cambridge University Hospitals NHS Foundation Trust, Addenbrooke's Hospital
Lung Function Unit, Box 40 Cambridge Biomedical Campus Hills Road
United Kingdom

Sponsor information


Cambridge Respiratory Innovations Ltd

Sponsor details

The Grange
20 Market Street
CB24 4QG
United Kingdom

Sponsor type




Funder type


Funder name

The Small Business Research Initiative for Healthcare (SBRI Healthcare)

Alternative name(s)

Funding Body Type

Funding Body Subtype


Results and Publications

Publication and dissemination plan

The first publication from the study will be a poster at the 2017 European Respiratory Society conference. Further publications are planned in high impact peer-reviewed journals.

IPD sharing statement
The datasets generated and/or analysed during the current study are not expected to be made publicly available due to commercial sensitivity with the development of N-Tidal technology and personal respiratory monitors.

Intention to publish date


Participant level data

Not expected to be available

Basic results (scientific)

See additional file ISRCTN56492264_BasicResults_25July17.pdf

Publication list

Publication citations

Additional files

Editorial Notes

10/05/2019: No publications found. Verifying results with principal investigator. The intention to publish date was changed from 01/08/2018 to 01/08/2019. 01/08/2017: The basic results of this trial have been uploaded as an additional file. 25/07/2017: Publication and dissemination plan and IPD sharing statement added.