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The Cyclocapnic Method for Measurement of Chemosensitivity

The recruitment status of this study is unknown. The completion date has passed and the status has not been verified in more than two years.
Verified January 2010 by Imperial College London.
Recruitment status was:  Recruiting
ClinicalTrials.gov Identifier:
First Posted: January 14, 2010
Last Update Posted: January 14, 2010
The safety and scientific validity of this study is the responsibility of the study sponsor and investigators. Listing a study does not mean it has been evaluated by the U.S. Federal Government. Read our disclaimer for details.
Information provided by:
Imperial College London

We aim to test our method for measuring chemosensitivity (the ventilatory response to a change in carbon dioxide), which uses sinusoidal carbon dioxide stimuli.


  • Carbon dioxide sensitivity is dependent on the cycle time over which we administer the gas (frequency).
  • Chemoreflex gain decreases as deadspace increases.

Condition Intervention Phase
Periodic Breathing Heart Failure Other: carbon dioxide Phase 1

Study Type: Interventional
Study Design: Intervention Model: Single Group Assignment
Masking: None (Open Label)
Primary Purpose: Basic Science
Official Title: Developing an Improved Measure of Chemosensitivity for the Study of Periodic Breathing in Heart Failure: the Cyclocapnic Method

Resource links provided by NLM:

Further study details as provided by Imperial College London:

Primary Outcome Measures:
  • Chemoreflex gain as measured by cyclocapnic method [ Time Frame: every minute ]

Estimated Enrollment: 45
Study Start Date: January 2008
Estimated Study Completion Date: October 2010
Estimated Primary Completion Date: April 2010 (Final data collection date for primary outcome measure)
Intervention Details:
    Other: carbon dioxide
    sinusoidal carbon dioxide administration
Detailed Description:
We will apply a new method for the measurement of chemosensitivity (how sensitive a person is to changes in carbon dioxide), which is one of the principle determinants of whether people with heart failure develop abnormal breathing patterns We have shown in a pilot study that administering sinusoidal patterns of inspired carbon dioxide produces similar sinusoidal responses in ventilation. We aim to test our method for measuring chemosensitivity, which uses sinusoidal carbon dioxide stimuli (similar to those that drive the oscillations in ventilation found in periodic breathing). We aim to show that how the cycle time of carbon dioxide administered affects the resulting ventilatory oscillations and therefore that when measuring the chemoreflex clinically, it is important to deliver carbon dioxide stimuli that replicate the cycle time of oscillations in carbon dioxide seen in periodic breathing (typically approximately one minute).

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Ages Eligible for Study:   18 Years to 80 Years   (Adult, Senior)
Sexes Eligible for Study:   Male
Accepts Healthy Volunteers:   Yes

Inclusion Criteria:

  • Heart failure subjects with stable cardiorespiratory control to be recruited from our institution's specialist heart failure clinic.
  • Normal healthy volunteers, with normal systolic function.

Exclusion Criteria:

  • We will exclude patients with chronic respiratory disease (every patient will have formal lung function testing on entrance into the study) or unstable coronary artery disease (myocardial infarction or unstable angina within the past 3 months).
  • In addition any subjects receiving treatment with morphine and derivatives, theophylline, oxygen, benzodiazepines or acetazolamide will be excluded as these affect chemosensitivity.
  Contacts and Locations
Information from the National Library of Medicine

To learn more about this study, you or your doctor may contact the study research staff using the contact information provided by the sponsor.

Please refer to this study by its ClinicalTrials.gov identifier (NCT number): NCT01049256

Contact: Darrel P Francis, MD +44 207 594 1093 darrel.francis@imperial.ac.uk

United Kingdom
St Mary's Hospital Recruiting
London, United Kingdom, W2 1LA
Contact: Resham Baruah, MB BS    020 75941027    resham.baruah@imperial.ac.uk   
Contact: Darrel P Francis, MD    +44 207 594 1093    darrel.francis@imperial.ac.uk   
Sponsors and Collaborators
Imperial College London
Principal Investigator: Darrel P Francis, MD Imperial College London
  More Information

Responsible Party: Darrel Francis, Imperial College
ClinicalTrials.gov Identifier: NCT01049256     History of Changes
Other Study ID Numbers: 07/H0712/129
First Submitted: January 13, 2010
First Posted: January 14, 2010
Last Update Posted: January 14, 2010
Last Verified: January 2010

Keywords provided by Imperial College London:
Periodic breathing
Heart Failure

Additional relevant MeSH terms:
Heart Failure
Respiratory Aspiration
Heart Diseases
Cardiovascular Diseases
Respiration Disorders
Respiratory Tract Diseases
Pathologic Processes