Obstructive Sleep Apnea and Oxygen Therapy: A Systematic Review of the Literature and Meta-Analysis

Background: Hypoxemia is an immediate consequence of obstructive sleep apnea. Oxygen (O-2) administration has been used as an alternative treatment in patients with obstructive sleep apnea (OSA) who do not adhere to continuous positive airway pressure (CPAP) in order to reduce the deleterious effects of intermittent hypoxemia during sleep. This systematic review aims to investigate the effects of O-2 therapy on patients with OSA. Method: We conducted a systematic search of the databases Medline, Embase, Cochrane Central Register of Controlled Trials (1st Quarter 2011), Cochrane Database of Systematic Reviews (from 1950 to February 2011). Our search strategy yielded 4,793 citations. Irrelevant papers were excluded by title and abstract review, leaving 105 manuscripts. We reviewed all prospective studies that included: (1) a target population with obstructive sleep apnea, (2) O-2 therapy and/or CPAP as a study intervention, (3) the effects of O-2 on the apnea-hypopnea index (AHI), nocturnal hypoxemia, or apnea duration. Results: We identified 14 studies including a total of 359 patients. Nine studies were of single cohort design, while 5 studies were randomized control trials with 3 groups (CPAP, oxygen, and placebo/sham CPAP). When CPAP was compared to O-2 therapy, all but one showed a significant improvement in AHI. Ten studies demonstrated that O-2 therapy improved oxygen saturation vs. placebo. However, the average duration of apnea and hypopnea episodes were longer in patients receiving O-2 therapy than those receiving placebo. Conclusion: This review shows that O-2 therapy significantly improves oxygen saturation in patients with OSA. However, it may also increase the duration of apnea-hypopnea events.