ĐẶC ĐIỂM VÀ MỐI TƯƠNG QUAN CỦA CÁC CHỈ SỐ GIẢM OXY MÁU VỚI CHỈ SỐ NGƯNG-GIẢM THỞ Ở BỆNH NHÂN NGƯNG THỞ KHI NGỦ DO TẮC NGHẼN

Abstract

 Objective: This study aimed to investigate the characteristics of oxygen desaturation indices and to
determine their correlation with the apnea–hypopnea index (AHI) in patients with obstructive sleep apnea
(OSA). Methods: A retrospective analytical study was conducted on 374 adult patients who underwent
overnight polysomnography and were diagnosed with OSA at the University Medical Center Ho Chi Minh
City from September 2023 to July 2025. Oxygen desaturation indices, including the oxygen desaturation
index (ODI), mean oxygen saturation (mean SpO₂), lowest oxygen saturation (SpO₂ nadir), and total time
with SpO₂ below 90% (T90), were collected and analyzed. Results: The mean age of the study population
was 50.7 ± 14.8 years; males accounted for 80.0%, and obesity was predominant (74.9%). Severe OSA
was the most common category (52.9%), with a mean AHI of 37.2 ± 23.8 events/hour for the entire cohort.
The mean ODI was 37.2 ± 24.1 events/hour. Mean SpO₂ was 93 ± 4%, SpO₂ nadir was 71 ± 12%, and the
mean T90 was 1.2 ± 1.5 hours. ODI and T90 increased progressively with OSA severity, whereas mean
SpO₂ and SpO₂ nadir decreased accordingly; differences among OSA severity groups were statistically
significant (p < 0.001). Correlation analysis demonstrated a very strong positive correlation between AHI
and ODI (r = 0.883) and a strong positive correlation between AHI and T90 (r = 0.655). In contrast, AHI
showed moderate negative correlations with mean SpO₂ (r = -0.563) and SpO₂ nadir (r = -0.585), all of
which were statistically significant (p < 0.001). Conclusion: Oxygen desaturation indices are closely
associated with OSA severity and clearly reflect the hypoxic burden in patients, thereby supporting disease
severity assessment and risk stratification in clinical practice.