The Cyclocapnic Method for Measurement of Chemosensitivity

The recruitment status of this study is unknown because the information has not been verified recently.
Verified January 2010 by Imperial College London.
Recruitment status was  Recruiting
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Imperial College London Identifier:
First received: January 13, 2010
Last updated: NA
Last verified: January 2010
History: No changes posted

January 13, 2010
January 13, 2010
January 2008
April 2010   (final data collection date for primary outcome measure)
Chemoreflex gain as measured by cyclocapnic method [ Time Frame: every minute ] [ Designated as safety issue: No ]
Same as current
No Changes Posted
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The Cyclocapnic Method for Measurement of Chemosensitivity
Developing an Improved Measure of Chemosensitivity for the Study of Periodic Breathing in Heart Failure: the Cyclocapnic Method

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.
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).
Phase 1
Intervention Model: Single Group Assignment
Masking: Open Label
Primary Purpose: Basic Science
  • Periodic Breathing
  • Heart Failure
Other: carbon dioxide
sinusoidal carbon dioxide administration
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*   Includes publications given by the data provider as well as publications identified by Identifier (NCT Number) in Medline.
October 2010
April 2010   (final data collection date for primary outcome measure)

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.
18 Years to 80 Years
Contact: Darrel P Francis, MD +44 207 594 1093
United Kingdom
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Darrel Francis, Imperial College
Imperial College London
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Principal Investigator: Darrel P Francis, MD Imperial College London
Imperial College London
January 2010

ICMJE     Data element required by the International Committee of Medical Journal Editors and the World Health Organization ICTRP