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Exhaled Carbon Monoxide (eCO) for Diffusing Capacity (DLCO) Correction

This study has been completed.
Information provided by (Responsible Party):
Eric Kleerup, University of California, Los Angeles Identifier:
First received: May 14, 2010
Last updated: November 7, 2011
Last verified: November 2011
The purpose of this study is to check the accuracy of a procedure called exhaled carbon monoxide (eCO) testing. Exhaled carbon monoxide is used by physicians to help assess breathing in people with conditions like asthma and emphysema. eCO may be used to correct another breathing test (called diffusing capacity, or DLCO). Blood collection is usually required to correct the DLCO, so validation of the eCO test may help avoid that blood collection.

Condition Intervention
Lung Diseases
Other: eCO testing

Study Type: Interventional
Study Design: Intervention Model: Single Group Assignment
Masking: Open Label
Primary Purpose: Diagnostic
Official Title: Validation of Exhaled Carbon Monoxide for DLCO Correction

Resource links provided by NLM:

Further study details as provided by University of California, Los Angeles:

Primary Outcome Measures:
  • Exhaled carbon monoxide as a predictor of carboxyhemoglobin [ Time Frame: 1 year ]
    Exhaled carbon monoxide will be evaluated as a predictor of carboxyhemoglobin and change in diffusing capacity with increasing carboxyhemoglobin

Enrollment: 100
Study Start Date: May 2010
Study Completion Date: November 2011
Primary Completion Date: November 2011 (Final data collection date for primary outcome measure)
Arms Assigned Interventions
PFT's, eCO, and pulse oximetry
All subjects in the study will undergo complete pulmonary function testing (spirometry, blood collection for carboxyhemoglobin, diffusing capacity); exhaled carbon-monoxide testing, and pulse oximetry.
Other: eCO testing
exhaled carbon monoxide testing measured in duplicate on each of 2 machines immediately prior to the carboxyhemoglobin blood draw and four minutes after the clinical measurement of DLCO

Detailed Description:
The purpose of this study is to check the accuracy of a procedure called exhaled carbon monoxide (eCO) testing. Exhaled carbon monoxide is used by physicians to help assess breathing in people with conditions like asthma and emphysema. 100 subjects who are at least 18 years of age will be invited to participate. The first 50 subjects (Part 1) must have had pulmonary function testing (spirometry, diffusing capacity and CO-oximetry) for clinical reasons ordered by their own physician in order to enroll. The second 50 subjects (Part 2) may undergo this testing as part of the study. Participation requires 1 visit, during which subjects will undergo breathing tests, have blood collected, and answer 3 questions. The number of breathing tests will depend on which part of the study subjects are in. Subjects participating in Part 1 of the study will undergo 2-4 additional diffusing capacity (breathing) tests. (Clinical tests require 2-4 tests. This study requires 6. The number of research tests done depends on the number of clinical tests done. Subjects participating in Part 2 of the study who have not had clinical breathing tests ordered by their physician will undergo 1 spirometry (breathing) test (3-8 blows into a tube), 6 diffusing capacity (breathing tests), and blood draw. All subjects will undergo eCO testing (blowing into a machine) before the breathing tests and after the breathing tests. The visit in Part 1 of the study will take about 30 minutes. The visit in Part 2 of the study will take about 30 minutes for subjects who have undergone clinical breathing tests recently, and about 1 ½ hours for those who must undergo breathing tests for the research. Subjects will also have their pulse oximetry (using a standard finger clip) performed at the same time as each eCO testing.

Ages Eligible for Study:   18 Years and older   (Adult, Senior)
Sexes Eligible for Study:   All
Accepts Healthy Volunteers:   Yes

Inclusion Criteria:

  • Patients who will at minimum have spirometry, diffusing capacity and CO-oximetry performed for any clinical indication (Part 1 only)
  • Willingness to under go the study procedures.
  • Ability to give written informed consent to participate in the study.

Exclusion Criteria:

  • Subjects on oxygen therapy within 1 hour. High levels of oxygen are used to displace CO in cases of toxicity. Presumably those recently on lower flows of oxygen are not in a steady state for several half-lives.
  • Self-reported smoking within 1-hour.
  • Significant exercise within 15 minutes
  • Recent (within 2 hrs) alcohol consumption (alcohol can interfere with the DLCO measurement)
  • Subjects unwilling to remove nail polish from one finger
  • Known atypical hemoglobin types (e.g. sickle cell trait or disease, thalassemia etc). The binding and release of oxygen and presumably CO is altered in these types of hemoglobinopathies
  • History of known or suspected alveolar hemorrhage. Free hemoglobin or red cells in the alveolus markedly raise the DLCO and theoretically might alter the eCO.
  • Known or suspected intestinal bacterial overgrowth. Although the cross reactivity of the CO sensor for hydrogen is <2%, high values of hydrogen from bacterial overgrowth, may lead to erroneous CO measurements.
  • Tracheostomy or inability to form a tight seal around the mouthpiece.
  • Prior participation in the same part of this study (i.e., subjects can participate in Part 1 and Part 2, but not twice in Part 1, or twice in Part 2)
  • Inability to perform spirometry and diffusing capacity
  • Inability to consent
  • Other diseases or conditions that may, in the opinion of the investigator, result in invalid pulmonary function tests or eCO measurement.
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Please refer to this study by its identifier: NCT01126047

United States, California
Los Angeles, California, United States, 90095
West LA VA
Los Angeles, California, United States, 90095
Sponsors and Collaborators
University of California, Los Angeles
Principal Investigator: Michelle R Zeidler, MD UCLA, VA
  More Information

Responsible Party: Eric Kleerup, Clinical Professor, University of California, Los Angeles Identifier: NCT01126047     History of Changes
Other Study ID Numbers: eCO
Study First Received: May 14, 2010
Last Updated: November 7, 2011

Keywords provided by University of California, Los Angeles:
Lung Diseases

Additional relevant MeSH terms:
Lung Diseases
Respiratory Tract Diseases
Carbon Monoxide
Molecular Mechanisms of Pharmacological Action
Neurotransmitter Agents
Physiological Effects of Drugs processed this record on May 25, 2017