Regional cerebral oxygen saturation in the healthy population of western Sichuan: a multicenter cross-sectional study

Regional cerebral oxygen saturation (rSO₂) may vary in healthy individuals with different characteristics. Therefore, this study aimed to explore rSO₂ in a healthy population of western Sichuan. This cross-sectional study enrolled healthy volunteers from the Health Management Center and Inpatient Department of Ya'an People's Hospital, Ya'an Vocational and Technical College, Ya'an Geriatric University, and Liziping Yi Township in Shimian County, Ya'an City, Sichuan Province. Brain rSO₂ was measured by near-infrared spectroscopy (NIRS) between January 2020 and December 2022. A total of 661 volunteers were enrolled, with a mean age of 28.3 ± 23.1 years old and 276 males. There was significantly higher rSO₂ of the left brain in females (63.46 ± 3.01 vs. 63.17 ± 2.90, P = 0.015), males (63.91 ± 3.54 vs. 63.42 ± 3.32, P = 0.002), Han (65.10 ± 3.67 vs. 64.38 ± 3.43, P < 0.001), and volunteers aged 14-59 years (P < 0.05) compared with the right brain. Volunteers with Han ethnicity had significantly higher rSO₂ than those with Yi ethnicity (64.65 ± 3.29 vs. 62.68 ± 3.66, P < 0.001). Volunteers with past illness had significantly lower rSO₂ than those without past illness (62.41 ± 3.06 vs. 62.68 ± 3.66, P = 0.021). Pearson correlation analysis showed a significantly negative correlation of rSO₂ with age, ethics, past illness, and body mass index (BMI) but a significantly positive correlation with head circumference and height (all P < 0.05). The rSO₂ values in the left brain are significantly higher than in the right brain. Sex, ethnicity, age, BMI, and past illness are closely related to rSO₂ values in the healthy population.