Who Needs Oxygen with Positive Airway Pressure Therapy?

Journal of Clinical Sleep Medicine, Vol. 13, No. 1, 2017 The diagnosis and management of obstructive sleep apnea (OSA) are increasingly being performed in the home. In the home management pathway, patients with high pretest probability for OSA are first tested using home sleep apnea testing and if positive for OSA, are treated with automatic positive airway pressure (APAP). The home management pathway has been validated by multiple investigators1–3 and is considered an alternative pathway in guidelines for the evaluation and management of OSA.4 However, there are limitations to the routine use of this pathway. First, studies on home sleep apnea testing have generally excluded patients with significant comorbidities such as morbid obesity (usually body mass index greater than 50 kg/m2), chronic obstructive pulmonary disease (COPD), congestive heart failure (CHF), and disorders associated with hypoventilation. Second, if the patient has been prescribed autoPAP, the sleep physician will not know if the patient has residual hypoxia while on treatment with autoPAP because these devices measure a residual apnea-hypopnea index but not residual low oxyhemoglobin saturation. This could result in undertreatment of the patient’s sleep-disordered breathing. However, there have been no previous studies that have examined which patients require oxygen in addition to positive airway pressure (PAP) therapy and how to predict who those patients are pretitration. In this issue of the Journal of Clinical Sleep Medicine, Shetty and colleagues5 assess the relationship between medical comorbidities (COPD, CHF, and/or obesity), positional change in pulse oximetry, and need for nocturnal oxygen therapy added to PAP therapy during in-laboratory overnight PAP titration. The study analyzed data obtained retrospectively from 200 patients with OSA, of whom 50 required oxygen supplement in addition to PAP therapy during sleep. Positional change in oxyhemoglobin saturation was measured as the difference between sitting and supine positions using pulse oximetry data during the clinic visit and the sleep study (performed within 3 mo), respectively. The presence of the following predictors: COPD, body mass index greater than 35 kg/m2, age older than 50 y, and a more than 5% drop in oxyhemoglobin saturation between upright and supine positions are associated with increased odds of needing oxygen added to PAP therapy. However, having less than two of these predictors provided a COMMENTARY