PURPOSE: The prevalence of sleep-breathing disorders (SBD) is much higher in chronic obstructive pulmonary disease (COPD) patients than in general population but not much is known about the prevalence of SBD in COPD patients who develop cor pulmonale. The purpose of this study was to compare the occurrence of SBD in two groups of COPD patients: group I, COPD with cor pulmonale; and group II, COPD without cor pulmonale.
METHODS: SETTING: Referral sleep laboratory of Vallabhbhai Patel Chest Institute, Delhi University, India. PATIENTS: 21 patients of cor pulmonale (with mean pulmonary artery pressure > 25 mm Hg) vs 29 patients of COPD. MEASUREMENTS: Whole night polysomnography (Medcare polygraph, Medcare Flaga, Reykjavik, Iceland) was done in the sleep laboratory. SBD included obstructive sleep apnea (OSA), central sleep apnea (CSA) and nocturnal desaturation. OSA and CSA were defined as apnea-hypopnea index of more than five per hour for obstructive and central sleep apneas-hypopneas respectively. Nocturnal destaration was defined as oxygen saturation <90% by pulse oximetry (SpO2) for more than 10% of the total sleep time or requirement of supplemental oxygen to maintain SpO2 level at ≥90%.
RESULTS: Eight out of 21 (38%) patients in cor pulmonale group and 16 out of 29 (55%) patients in COPD group had obstructive sleep apnea (p=0.35). Neither of the groups had significant hourly rate for central sleep apneas. 15 out of 21 (71.43%) patients in cor pulmonale group and ten out of 29 (34.48%) patients in COPD group were nocturnal desaturators (p=0.02). The average minimum saturation of oxygen in arterial blood was 87.33 ± 7.75% vs 91.84 ± 4.63% in cor pulmonale and COPD groups respectively (p=0.02).
CONCLUSION: As compared to COPD patients, patients of COPD with cor pulmonale do not have any increased risk of developing sleep apneas but they have significantly higher rates of nocturnal desaturation and lesser average minimum saturation.
CLINICAL IMPLICATIONS: COPD patients who develop cor pulmonale show higher occurrence of sleep-breathing disorders.
DISCLOSURE: Amit Bansal, No Financial Disclosure Information; No Product/Research Disclosure Information