Therapeutic effects of oxygen inhalation for obstructive sleep apnea patients with high carotid body chemosensitivity

Obstructive sleep apnea (OSA) is a heterogenous disease with several pathophysiological phenotypes; therefore, treatment must be tailored accordingly. This study aimed to explore the therapeutic effects of oxygen (O2) inhalation in OSA patients with high carotid body (CB) chemosensitivity (hCBC). CB chemosensitivity (CBC) was measured with the Dejours test in this single-arm clinical trial, and hCBC was defined as a respiratory rate reduction of > 12% after inhalation of pure O2. Subjects with hCBC were enrolled for two overnight polysomnographies, the first one with air inhalation and the second one with O2 inhalation. The morning blood pressure after awakening was measured along with heart rate variability (HRV) metrics, including high-frequency power (HF), low-frequency power (LF), and the LF/HF ratio. A cohort of 74 OSA patients exhibiting hCBC were enrolled. The mean CBC, as measured by the Dejours test, was 17.4 ± 4.2%. The apnea–hypopnea index (AHI) was significantly lower when the patients inhaled O2 (19.92 ± 13.49 events/h) compared to when they inhaled air (26.53 ± 12.18 events/h; P = 0.003). O2 inhalation also improved the nadir pulse O2 saturation (SpO2) (75.81 ± 12.44% vs. 83.91 ± 6.97%, P = 0.0021), decreased the blood pressure in the morning from 107.3 ± 8.32 mmHg (air inhalation) to 94.08 ± 5.93 mmHg (O2 inhalation), and lowered the HRV, as demonstrated by changes in the natural logarithm-transformed values of LF (8.933 ± 1.472 ln ms2 vs. 6.231 ± 2.136 ln ms2, P < 0.001), and the LH/HF ratio (1.381 ± 0.431 vs. 1.124 ± 0.319, P = 0.025). O2 inhalation decreased symptom severity in OSA patients with hCBC as well as alleviated cardiovascular complications related to OSA.