@article {6003, title = {Automated recognition of obstructive sleep apnea syndrome using support vector machine classifier.}, journal = {IEEE Trans Inf Technol Biomed}, volume = {16}, year = {2012}, month = {2012 May}, pages = {463-8}, abstract = {

Obstructive sleep apnea (OSA) is a common sleep disorder that causes pauses of breathing due to repetitive obstruction of the upper airways of the respiratory system. The effect of this phenomenon can be observed in other physiological signals like the heart rate variability, oxygen saturation, and the respiratory effort signals. In this study, features from these signals were extracted from 50 control and 50 OSA patients from the Sleep Heart Health Study database and implemented for minute and subject classifications. A support vector machine (SVM) classifier was used with linear and second-order polynomial kernels. For the minute classification, the respiratory features had the highest sensitivity while the oxygen saturation gave the highest specificity. The polynomial kernel always had better performance and the highest accuracy of 82.4\% (Sen: 69.9\%, Spec: 91.4\%) was achieved using the combined-feature classifier. For subject classification, the polynomial kernel had a clear improvement in the oxygen saturation accuracy as the highest accuracy of 95\% was achieved by both the oxygen saturation (Sen: 100\%, Spec: 90.2\%) and the combined-feature (Sen: 91.8\%, Spec: 98.0\%). Further analysis of the SVM with other kernel types might be useful for optimizing the classifier with the appropriate features for an OSA automated detection algorithm.

}, keywords = {Adolescent, Adult, Case-Control Studies, Child, Heart Rate, Humans, Middle Aged, Oximetry, Oxygen, Pattern Recognition, Automated, Polysomnography, Respiratory Rate, Sleep Apnea, Obstructive, Support Vector Machine}, issn = {1558-0032}, doi = {10.1109/TITB.2012.2185809}, author = {Al-Angari, Haitham M and Sahakian, Alan V} } @article {1411, title = {Obesity is associated with a lower resting oxygen saturation in the ambulatory elderly: results from the cardiovascular health study.}, journal = {Respir Care}, volume = {58}, year = {2013}, month = {2013 May}, pages = {831-7}, abstract = {

BACKGROUND: The contribution of obesity to hypoxemia has not been reported in a community-based study. Our hypothesis was that increasing obesity would be independently associated with lower SpO2 in an ambulatory elderly population.

METHODS: The Cardiovascular Health Study ascertained resting SpO2 in 2,252 subjects over age 64. We used multiple linear regression to estimate the association of body mass index (BMI) with SpO2 and to adjust for potentially confounding factors. Covariates including age, sex, race, smoking, airway obstruction (based on spirometry), self reported diagnosis of emphysema, asthma, heart failure, and left ventricular function (by echocardiography) were evaluated.

RESULTS: Among 2,252 subjects the mean and median SpO2 were 97.6\% and 98.0\% respectively; 5\% of subjects had SpO2 values below 95\%. BMI was negatively correlated with SpO2 (Spearman R = -0.27, P < .001). The mean difference in SpO2 between the lowest and highest BMI categories (< 25 kg/m(2) and >= 35 kg/m(2)) was 1.33\% (95\% CI 0.89-1.78\%). In multivariable linear regression analysis, SpO2 was significantly inversely associated with BMI (1.4\% per 10 units of BMI, 95\% CI 1.2-1.6, for whites/others, and 0.87\% per 10 units of BMI, 95\% CI 0.47-1.27, for African Americans).

CONCLUSIONS: We found a narrow distribution of SpO2 values in a community-based sample of ambulatory elderly. Obesity was a strong independent contributor to a low SpO2, with effects comparable to or greater than other factors clinically associated with lower SpO2.

}, keywords = {African Americans, Age Factors, Aged, Aged, 80 and over, Body Mass Index, European Continental Ancestry Group, Female, Humans, Male, Obesity, Oximetry, Oxygen, Smoking, Waist Circumference}, issn = {1943-3654}, doi = {10.4187/respcare.02008}, author = {Kapur, Vishesh K and Wilsdon, Anthony G and Au, David and Avdalovic, Mark and Enright, Paul and Fan, Vincent S and Hansel, Nadia N and Heckbert, Susan R and Jiang, Rui and Krishnan, Jerry A and Mukamal, Kenneth and Yende, Sachin and Barr, R Graham} }