Supplemental oxygen could potentially eliminate the rise in morning blood pressure (BP) among patients with obstructive sleep apnea (OSA) undergoing continuous positive airway pressure (CPAP) withdrawal.
Researchers recently made this determination based on the results of a study of patients with moderate to severe OSA. The goal of their study was to examine the impact of overnight supplemental oxygen compared with air (sham) on morning BP following CPAP withdrawal.
The primary outcome was defined as the change in home morning BP after CPAP withdrawal for 14 nights in patients receiving supplemental oxygen vs air, and secondary outcomes were oxygen desaturation index (ODI), apnea hypopnea index (AHI), and subjective and objective sleepiness (based on the Epworth sleepiness score and Oxford sleep resistance test, respectively.
Results of the study demonstrated that supplemental oxygen use nearly eliminated the morning BP rise and was associated with a significantly lower rise in mean systolic BP (-6.6 mmHg), mean diastolic BP (-4.6 mmHg), and median ODI (-23.8/h) following CPAP withdrawal compared with air.
However, no significant between-group differences were observed for AHI and subjective or objective sleepiness.
“Supplemental oxygen virtually abolished the rise in morning BP during CPAP withdrawal,” the researchers concluded. “Supplemental oxygen substantially reduced intermittent hypoxia, but had a minimal effect on markers of arousal (including AHI), subjective or objective sleepiness. Therefore, intermittent hypoxia, and not recurrent arousals, appears to be the dominant cause of daytime increases in BP in OSA.”
Turnbull CD, Sen D, Kohler M, Petousi N, Stradling JR. Effect of supplemental oxygen on blood pressure in OSA: a randomized, CPAP withdrawal trial [Published online July 20, 2018]. Am J Respir Crit Care Med. http://www.thoracic.org/about/newsroom/press-releases/resources/osa-and-bp.pdf