Unanticipated Nocturnal Oxygen Requirement during Positive Pressure Therapy for Sleep Apnea and Medical Comorbidities

Study objectives: Home-based management of sleep-disordered breathing (SDB) generally excludes patients with significant medical comorbidities, but such an approach lacks scientific evidence. The current study examined whether significant medical comorbidities are associated with persistent hypoxia that requires unanticipated nocturnal O₂ supplementation to positive airway pressure (PAP) therapy. Conceivably, in such patients, home-based management of SDB may not detect or therefore adequately treat persistent hypoxia.

Methods: In this retrospective study of 200 patients undergoing laboratory-based polysomnography, we ascertained significant medical comorbidities (chronic obstructive pulmonary disease, congestive heart failure, and morbid obesity) and their association with the need for unanticipated O₂ supplementation to PAP therapy. Postural oxygen (SpO₂) desaturations between upright and reclining positions were determined during calm wakefulness.

Results: Postural change in SpO₂ during calm wakefulness was greater in patients who eventually needed nocturnal O₂ supplementation to PAP therapy than those needing PAP therapy alone (p < 0.0001). The presence of chronic obstructive pulmonary disease (odds ratio [OR] 6.0; 95% confidence interval [CI]; 2.1, 17.5; p = 0.001), morbid obesity (OR 3.6; 95% CI 1.9, 7.0; p < 0.0001), and age older than 50 y (OR 2.8; 95% CI 1.3, 5.9; p = 0.007) but not heart failure were associated with unanticipated need for nocturnal O₂ supplementation. A clinical prediction rule of less than two determinants (age older than 50 y, morbid obesity, chronic obstructive pulmonary disease, and postural SpO₂ desaturation greater than 5%) had excellent negative predictive value (0.92; 95% CI 0.85, 0.96) and likelihood ratio of negative test (0.08; 95% CI 0.04, 0.16).

Conclusions: Medical comorbidities can predict persistent hypoxia that requires unanticipated O₂ supplementation to PAP therapy. Such findings justify the use of medical comorbidities to exclude home management of SDB.

Commentary: A commentary on this article appears in this issue on page 7.