Oxygen desaturation during sleep as a determinant of the 'Blue and Bloated' syndrome

Certain patients with chronic obstructive pulmonary disease may be classified as blue bloaters or pink puffers. Recent studies suggest that physiologic changes during sleep contribute to the clinical expression of these syndromes. To investigate this, we monitored four blue bloaters and six pink puffers during one night's sleep to determine the incidence of sleep disordered breathing (SDB) and of arterial oxygen desaturation. There were no significant differences between the two groups for sleep period time, awake oxygen saturation, or the number of episodes of SDB. Blue bloaters had lower baseline oxygen saturations, more episodes of arterial oxygen desaturation, and larger falls in oxygen saturation and spent more time at low levels of oxygen saturation while asleep. We propose that the degree and the duration of sleep hypoxemia of blue bloaters but not of pink puffers may contribute to early pulmonary hypertension and cor pulmonale.