Effect of Supplemental Oxygen on Blood Pressure in Obstructive Sleep Apnea (SOX). A Randomized Continuous Positive Airway Pressure Withdrawal Trial

• DOI: 10.1164/rccm.201802-0240oc
• Publication Date: 2018-07-20T07:03:06Z
• Authors: Chris D. Turnbull; Dushendree Sen; Malcolm Kohler; Nayia Petousi; John R. Stradling
• Keywords: Epworth Sleepiness Scale; Interquartile range; Hypoxia; Intermittent hypoxia; Crossover study; Apnea–hypopnea index

Rationale: Obstructive sleep apnea (OSA) is associated with systemic hypertension. Either overnight intermittent hypoxia, or the recurrent arousals that occur in OSA, could cause daytime increases blood pressure (BP).Objectives: To establish role of hypoxia increased morning BP patients OSA.Methods: Randomized, double-blinded, crossover trial assessing effects supplemental oxygen versus air (sham) on BP, after continuous positive airway (CPAP) withdrawal moderate to severe OSA. The primary outcome was change home CPAP for 14 nights, air. Secondary outcomes included desaturation index (ODI), apnea–hypopnea (AHI), subjective sleepiness (Epworth Sleepiness Scale score), and objective (Oxford Sleep Resistance Test).Measurements Main Results: Supplemental virtually abolished rise and, compared air, significantly reduced mean systolic (−6.6 mm Hg; 95% confidence interval [CI], −11.3 −1.9; P = 0.008), diastolic (−4.6 CI, −7.8 −1.5; 0.006), median ODI (−23.8/h; interquartile range, −31.0 −16.3; < 0.001) withdrawal. There no significant difference, AHI, sleepiness, sleepiness.Conclusions: during substantially but had a minimal effect markers arousal (including AHI), sleepiness. Therefore not arousals, appears be dominant