Objective: To study the nocturnal dynamic change of SaO2 in patients with overlap syndrome at high altitude, and to evaluate the value and significance of oxygen desaturation in assessing disease severity by means of polysomnography.
Methods: 13 patients with COPD and 12 with overlap syndrome were conducted nocturnal sleep, respiratory and dynamic SaO2 mornitoring.
Results: AHIs in the both groups were 3.7 +/- 1.3 and 35.7 +/- 12.9 respectively, and there was a significant difference between these two groups (P < 0.001). There were significant difference between these two groups in ISaO2, MSaO2, HSaO2, SIT85 and DI4(P < 0.005-0.001). There was a liner correlation between AHI and DI4.
Conclusions: In patients with COPD, a suitable oxygen desaturation index has important clinical value on the preliminary selection and accurate diagnosis of SAS.