A7604 The possible relationship between airway resistance and surfactant proteins in OSA

Abstract

Objectives: 1) to assess the potential relationship between parameters of airway resistance measured by impulse oscillometry and serum concentrations of surfactant proteins (SPs) in OSA patients; 2) to further investigate possible involvement of airway resistance in OSA pathogenesis. Methods: This is a complementary cross-sectional study. 46 subjects who performed overnight polysomnography, plethysmograph, impulse oscillometry and measurement of serum SPs were enrolled. Subjects with apnea/hypopnea index ≥10events/h were defined as OSA group. Parameters of lung volume (FVC, FEV1, TLC) and airway resistance properties (Zrs5, R5–35, X5–35) were measured by plethysmograph and impulse oscillometry respectively and SP -A, B, C and D by ELISA. Results: OSA patient whose apnea/hypopnea index ≥10 events/h was diagnosed in 22 patients (47.8 %). Mean age and BMI was 45.6 ± 6.73 years and 28.3 ± 3.22 kg/m2 respectively.1) non-smoking OSA subjects displayed significantly lower serum SP-A (133.37 ± 29.43 vs 162.54 ± 24.96 ng/L, p = 0.021), SP-B (40.78 ± 4.28 vs 48.89 ± 6.37 ng/L, p = 0.002) and SP-D (15.68 ± 2.73 vs 19.32 ± 3.51 ng/L, p = 0.016), and significantly larger R5-R20 (0.08 ± 0.04 vs 0.05 ± 0.03 kPa/L/s, p = 0.035) than did non-OSA subjects; 2) significant negative correlation was observed between SP-D and respiratory system resistance at 5–20Hzs (r = − 0.438, p = 0.041) in non-smoking subjects, which was even stronger among subjects with BMI ≥ 28 kg/m2. Conclusion: OSA patients showed decreased serum SP-A, B and D and increased airway resistance. Serum SPs, particularly SP-D, were associated with increased airway resistance and might be involved in the pathogenesis of OSA in non-smoking patients.