Non-linear Poincare analysis of respiratory efforts in sleep apnea

OBJECTIVES: Obstructive sleep apnea (OSA) is a risk factor for hypertension, has effects on cardiovascular system and increases the sympathetic activity. The aim of the study was to evaluate the effectiveness of the non-linear Poincare plot analysis to predict OSA based on polysomnography (PSG). METHODS: The database of this study was collected by the sleep laboratory at the Philipps University in Marburg, Germany. It includes 24 PSG of men and women between 27-63 years old with obstructive and mixed sleep apnea. The start and end of apnea events in PSGs were marked. The Poincare plots of pre-apneic phase including 4-1 minutes before apnea were evaluated. Wilcoxon test was used for statistical analysis. RESULTS: Poincare analysis showed that the dynamics of chest and respiratory efforts changed two minutes before the apnea and SD1/SD2 ratios of these parameters significantly increased in the pre-apneic phase (p <= 0.01). The SD1/SD2 ratio of nasal airflow did not show significant difference even in episodes close to apnea. CONCLUSIONS: Our results suggest that Poincare plot parameters of PSG have the potential to be considered predictors of apnea with the ability to show the dynamic of changes, which could lead to pre-diagnosis or prediction of apnea about 2-3 minutes before its occurrence (Tab. 2, Fig. 4, Ref. 23). Text in PDF www.elis.sk.