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Authors:Kim, Jung Eun
Contributors:Titchenal, Charles A. (advisor)
Developmental & Reproductive Biology (department)
Exhaled carbon monoxide (eCO)
Pulmonary function test (PFT)
Date Issued:2019
Publisher:University of Hawai'i at Manoa
Abstract:Chronic lung diseases, such as chronic obstructive pulmonary disease (COPD) and asthma, are associated with considerable morbidity and mortality in the United States. COPD is currently the 4th leading cause of death in the United States and a major cause of morbidity. More than 26 million Americans have asthma, which accounts for 14.2 million doctor’s office visits each year, according to the Centers for Disease Control and Prevention (CDC). These lung diseases involve chronic inflammation and oxidative stress. However, the diseases are not diagnosed and treated efficiently in routine clinical practice because of the difficulties in monitoring inflammation. Consequently, it is often too late to alter respiratory dysfunction when patients’ referral for pulmonary function testing is delayed.
The purpose of this descriptive-correlational study was to explore the possible associations between pulmonary function test (PFT) measurements and exhaled carbon monoxide (eCO) levels as an indicator of generalized inflammation. Data analysis was conducted to determine a potential level of eCO to use as an indicator for conducting PFT. The contributions of demographic factors, patient history of smoking habits and drug use, and the medical diagnosis to the prediction of principal variables were also investigated.
A sample of 343 subjects, who were referred by their physicians for a routine care PFT, were recruited from the Queen’s Medical Center Pulmonary Lab in Honolulu, Hawaii. A study-specific information sheet was provided to the subjects as part of the informed consent process, and the subjects’ data were collected through a Demographic Data Questionnaire. Exhaled carbon monoxide (eCO) levels were measured with a portable carbon monoxide analyzer (MicroCO Meter), and the maximum values from three successive measurements were used in all calculations.
Carbon monoxide was detectable and measured reproducibly in the exhaled air of all subjects. Forced vital capacity (FVC), forced expiratory volume in the first second (FEV1), FEV1/FVC, and forced expiratory flow 25-75% (FEF25-75%)) decreased with elevated concentrations of eCO. In females, decreased lung volumes (total lung capacity, functional residual capacity, and residual volume) were associated with increased eCO levels. In males, increased lung volumes were associated with increased eCO levels. Diffusion capacity of lungs for carbon monoxide (DLCO) and eCO levels also showed the opposite correlation between females and males. DLCO of female subjects markedly decreased with increased levels of eCO while DLCO of male subjects mildly increased.
Appropriate cut-off points of eCO levels also were examined to determine the most efficient use of eCO as an indicator for PFT. The present study found that a cut-off point for eCO of 6 ppm provided the best relationship between sensitivity and specificity in predicting the need for PFT.
In conclusion, eCO measurement, which is noninvasive, quick, inexpensive, and easily administered by primary care physicians, could serve as a useful biomarker for monitoring patients with pulmonary diseases. Therefore, eCO measurement may be clinically useful as a diagnostic tool to identify inflammation and to serve as an indicator of the need to conduct PFT.
Description:Ph.D. Thesis. Ph.D. Thesis. University of Hawaiʻi at Mānoa 2019
Pages/Duration:109 pages
Rights:All UHM dissertations and theses are protected by copyright. They may be viewed from this source for any purpose, but reproduction or distribution in any format is prohibited without written permission from the copyright owner.
Appears in Collections: Ph.D. - Developmental and Reproductive Biology

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