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Exhaled carbon monoxide levels in obstructive sleep apnoea
Adrian Kis1, Martina Meszaros1, David Laszlo Tarnoki2
1Department of Pulmonology, Semmelweis University, 1/C Dios arok, 1125, Budapest, Hungary.
Journal of Breath Research
|May 21, 2019
Summary
Exhaled carbon monoxide (eCO) levels are elevated in severe obstructive sleep apnoea (OSA) patients, indicating increased oxidative stress. Smoking history significantly influences eCO, potentially explaining previous study variations.
Area of Science:
- Respiratory Medicine
- Sleep Medicine
- Biomarkers
Background:
- Obstructive sleep apnoea (OSA) is linked to chronic intermittent hypoxia, inflammation, and oxidative stress.
- Exhaled carbon monoxide (eCO) is a marker of oxidative stress, but studies in OSA are confounded by smoking status.
- Investigating eCO in OSA patients, considering smoking history, is crucial for accurate oxidative stress assessment.
Purpose of the Study:
- To investigate exhaled carbon monoxide (eCO) levels in obstructive sleep apnoea (OSA) patients and non-OSA controls.
- To compare eCO levels between evening and morning measurements.
- To assess the influence of smoking history and OSA severity on eCO levels.
Main Methods:
- Exhaled carbon monoxide (eCO) was measured in the evening and morning post-cardiorespiratory polygraphy.
- Participants included never-smoker OSA patients, ex-smoker OSA patients, current-smoker OSA patients, asthmatic OSA patients, COPD OSA patients, and never-smoker non-OSA controls.
- OSA diagnosis was based on the apnoea-hypopnoea index (AHI > 5/h).
Main Results:
- No significant difference in eCO was found between never-smoker OSA patients and controls in either evening or morning.
- A weak positive correlation was observed between eCO and AHI in the evening.
- Patients with severe OSA exhibited higher evening eCO levels than those with mild OSA.
- Ex-smoker, current-smoker, asthmatic, and COPD patients with OSA showed significantly higher eCO levels compared to non-smoker OSA patients.
Conclusions:
- Elevated eCO in severe OSA suggests accelerated oxidative stress in non-smokers.
- Smoking history is a significant confounding factor in eCO measurements for OSA patients.
- eCO remains a potentially useful tool for monitoring smoking cessation, despite minor biases in OSA patients.
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