ABSTRACT

Polysomnography (PSG) is a standard test used in the diagnosis of sleep-related breathing disorders. However, carbon dioxide monitoring is not routinely implemented in adults. This study aimed to investigate the necessity of full-night carbon dioxide monitoring during PSG in patients with pulmonary disease.

This retrospective cohort study enrolled adult patients with pulmonary disease and a control group who had PSG recordings and carbon dioxide monitoring for the last 3 years.

The study group included 36 individuals with asthma and 27 individuals with chronic obstructive pulmonary disease (COPD), whereas the control group included 52 individuals without any pulmonary diseases. The three groups were comparable in terms of age, gender and body mass index. Obstructive sleep apnoea syndrome was most commonly observed in patients in the COPD group (p=0.003). However, no difference was observed between patients in the asthma and control groups. Partial carbon dioxide pressure during wakefulness, non-rapid eye movement and rapid eye movement sleep were not significantly different among the three groups. In the control group, no patient had sleep-related hypoxemia and/or hypoventilation. Two patients with asthma (5.5%) and one patient with COPD (3.7%) had sleep-related hypoxemia, while one patient with COPD had sleep-related hypoventilation (3.7%).

In this study, sleep-related hypoventilation was not detected in any patient with asthma and in controls, while one patient with COPD was diagnosed with sleep-related hypoventilation upon routine carbon dioxide monitoring. Defining some criteria using additional correlations with respiratory parameters would help monitor carbon dioxide level in a selected subgroup of patients with COPD.

Keywords: Asthma, chronic obstructive pulmonary disease, obstructive sleep apnoea syndrome, polysomnography, carbon dioxide monitoring