Association between respiratory event-specific oxygen desaturation rate and blood pressure surge in obstructive sleep apnea.

To investigate the association between respiratory event-specific oxygen desaturation rate (ODR) and blood pressure (BP) surges in patients with obstructive sleep apnea (OSA). Oxygen desaturation events caused by apnea and hypopnea were analyzed to quantify ODR, representing the rate of oxygen consumption. Beat-to-beat systolic blood pressure was recorded using a pulse transit time (PTT)-based technique synchronized with PSG, and post-hypoxic BP responses (peak, amplitude, surge rate) were extracted. Vascular hypoxic reactivity was defined as the ratio of BP response to ODR. A total of 95,518 respiratory events from 297 patients were analyzed. In adjusted linear models, higher ODR was significantly associated with increased BP amplitude (β = 5.33, 95% CI: 3.00-7.67, p < 0.001) and BP surge rate (β = 0.52, 95% CI: 0.22-0.81, p = 0.001), but not with BP peak. A significant interaction between ODR and hypertension status was observed for both BP amplitude and surge rate. For each unit increase in BP amplitude/ODR, BP peak/ODR, and BP surge rate/ODR, the odds of hypertension increased by 2.3%, 0.2%, and 14.1%, respectively. ODR showed an independent relationship with post-hypoxic BP surge in OSA patients. The ratio of BP surges to ODR, reflecting vascular hypoxic reactivity, was associated with hypertension.