New Parameters In Determining The Severity Of Obstructive Sleep Apnea Hypopnea Syndrome In Adults

Objective: At present, the gold standard to dignose the obstructive sleep apnea hypopnea syndrome (OSAHS) is polysomnography. If at least 30 times of apnea and hypopnea in 7 hours of sleep every night, or the sleep apnea hyponea index (AHI)≥5 is present and the obstructive events occupy the main part, the OSAHS can be diagnosed. Although AHI and the lowest SaO₂ were used to determine the severity of this disease, 6–54% patients were misclassified. Many studies showed that hypoxemia leaded to excessive daytime somnolence(EDS), depression, drowsiness with impairment of life quality and systemic complications. However, it was the times of events with the SaO₂ below 90% that impacts patients'life quality. There were no close relevance between AHI and the quality of life, because AHI seemed unstable and too rough in judging the quality of life. So we need better indexes to determine the degree of OSAHS, which was the objective of this study.Methods: 59 patients were dignosed OSAHS and collected from the Department of Otolaryngology and Head and Neck Surgery in the Bethune International Peace Hospital from October2009 to October2010. They were asked to fill in the ESS and the QOL-OSAHS, and their names, sex, height, weight, EP scores, total scores of the QOL-OSAHS and the score in every dimensionality (symptom, daily working and living, social relationship, alertness and motion) were recorded. The results of the polysomnography were also evaluated, which included AHI, the total time of AP (s), the longest time of AP (s), the mean time of AP (s), AHTI, the lowest SaO₂, the index of SaO₂ below 90%, the times of SaO₂ below 90%, the total time of SaO₂ below 90% and the TST90. Patients whose polysomnography results did not satisfy the standard of OSAHS or who were unable to complete the polysomnography evaluation were excluded from the present study. Statistical analysis was performed with SPSS13.0. P value less than 0.05 was considered as significant difference. We used linear correlation analysis, multiple linear regression analysis and discriminant analysis. Particularly, the relevance between the QOL-OSAHS and the ESS was tested with the linear correlation analysis, then we looked for the new indexes that had close relationship with the EP scores, the total scores of the QOL-OSAHS and the score in every dimensionality. Finally, we established the equation to compute the degree of the disease.Results: Firstly, the total time of AP was selected from the breath indexes, because it would impact patients'quality of life and symptoms, while other breath indexes couldn't. The regression coefficients between the total time of AP and the total scores of the QOL-OSAHS, EP scores, symptoms dimensionality, daily working and living dimensionality and social relationship dimensionality were -0.326, 0.544, -0.531, -0.282 and -0.303, respectively, and the corresponding P value were 0.012, 0.000, 0.000, 0.030 and 0.020. In breath indexes, no indexes were found to impact the alertness dimensionality and emotion dimensionality. Secondly, in the SaO₂ indexes, three indexes were found to impact people'quality of life and symptoms. They were the total time of SaO₂ below 90%, the lowest SaO₂ and TST90. The regression coefficients between the total time of SaO₂ below 90% and the total scores of QOL-OSAHS, EP scores, symptoms dimensionality and daily working and living dimensionality were -0.599, 0.696, -0.754 and -0.469, respectively, and the corresponding P value were 0.000, 0.000, 0.000 and 0.005. The regression coefficients between TST90 and social relationship was -0.263(P=0.044<0.05). The regression coefficients between the lowest SaO₂ and the total scores of QOL-OSAHS, EP scores, symptoms dimensionality, the daily working and living dimensionality and alertness dimensionality were -0.378, 0.310, -0.318, -0.326 and -0.263, and the corresponding P value were 0.015, 0.033 0.023, 0.045 and 0.044. Thirdly, three equations could be established to compute the degree of OSAHS. The equation for the mild OSAHS was -59.676 + 1.537 (the lowest SaO₂) - 0.01 (the total time of SaO₂ below 90%)+91.848(TST90). The equation for the modest OSAHS was -63.391 + 1.58 (the lowest SaO₂) -0.01 (the total time of SaO₂ below 90%)+104.711(TST90). The equation for the severe OSAHS was -68.300 - 0.000044(the total time of AP) +1.618 (the lowest SaO₂) -0.01 (the total time of SaO₂ below 90%)+79.883 (TST90). The discriminant accuracy of the three equations were 73.3%, 38.5% and 76.5%. Finally, the coefficient between EP scores and the total scores was -0.409(P=0.001<0.05). The coefficient between EP scores and symptom was -0.532(P=0.000<0.05).Conclusion: It was demonstrated in the present study that the total time of AP which could affect patients'symptoms, daily working and living and the social relationship was more preferal than other breath indexes that couldn't show this impaction. Three indexes in the SaO₂ indexes were found to impact patients'symptoms and quality of life in various aspects. The total time of SaO₂ below 90% affected patients'symptoms, daily working and living. The link between TST90 and social relationship was tight. The lowest SaO₂ would affect patient's symptoms, daily working and living and alertness. Therefore, in judging apnea, the total time of AP was superior to other indexes, and three SaO₂ indexes should be considered comprehensively in judging hypoxemia.