Nocturnal oxygen desaturation in patients using long-term oxygen therapy for chronic airflow limitation

Nocturnal oxygen desaturation in patients receiving long-term oxygen therapy is described despite adequate daytime oxygenation (PaO2 greater than 8 kPa). Domiciliary oximetry overnight was performed on ten patients receiving long-term oxygen treatment for chronic airflow limitation: six patients were well saturated throughout the night with a fall in SaO2 to below 90% for only 1% of the monitoring time; four showed significant desaturation with a fall in SaO2 to below 90% for periods of 15-47% of the monitoring time.