Cardiovascular regulation in different sleep stages in the obstructive sleep apnea syndrome

Department of Physics, Humboldt-Universität zu Berlin, Germany.
Biomedizinische Technik/Biomedical Engineering (Impact Factor: 1.46). 08/2011; 56(4):207-13. DOI: 10.1515/BMT.2011.018
Source: PubMed


Heart rate and blood pressure variability analysis as well as baroreflex sensitivity have been proven to be powerful tools for the assessment of autonomic control in clinical practice. Their ability to detect systematic changes caused by different states, diseases and treatments shall be shown for sleep disorders. Therefore, we consider 18 normotensive and 10 hypertensive patients suffering from obstructive sleep apnea syndrome (OSAS) before and after a three-month continuous positive airway pressure (CPAP) therapy. Additionally, an age and sex matched control group of 10 healthy subjects is examined. Linear and nonlinear parameters of heart rate and blood pressure fluctuation as well as the baroreflex sensitivity are used to answer the question whether there are differences in cardiovascular regulation between the different sleep stages and groups. Moreover, the therapeutic effect of CPAP therapy in OSAS patients shall be investigated. Kruskal-Wallis tests between the sleep stages for each group show significant differences in the very low spectral component of heart rate (VLF/P: 0.0033-0.04 Hz, p<0.01) which indicates differences in metabolic activity during the night. Furthermore, the decrease of Shannon entropy of word distribution as a parameter of systolic blood pressure during non-REM sleep reflects the local dominance of the vagal system (p<0.05). The increased sympathetic activation of the patients leads to clear differences of cardiovascular regulation in different sleep stages between controls and patients. We found a significant reduction of baroreflex sensitivity in slow wave sleep in the OSAS patients (Mann-Whitney test, p<0.05) compared to controls, which disappeared after three months of CPAP therapy. Hence, our results demonstrate the ability of cardiovascular analyzes to separate between healthy and pathological regulation as well as between different severities of OSAS in this retrospective study.


Available from: Thomas Penzel, Dec 29, 2013
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    • "demonstrated that abnormal blood pressure variability (BPV) is a prognostic indicator of cardiovascular morbidity even in the absence of hypertension [14]. Studies in adults with OSA have reported depressed baroreflex sensitivity (BRS) [15] and increased BPV [16]. There is a circadian variation in BP across the night in adults [17]. "
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    ABSTRACT: Background: Obstructive sleep apnea (OSA) in adults has been associated with hypertension, low baroreflex sensitivity (BRS), a delayed heart rate response to changing blood pressure (heart period delay [HPD]), and increased blood pressure variability (BPV). Poor BRS may contribute to hypertension by impairing the control of blood pressure (BP), with increased BPV and HPD. Although children with OSA have elevated BP, there are scant data on BRS, BPV, or HPD in this group. Methods: 105 children ages 7-12 years referred for assessment of OSA and 36 nonsnoring controls were studied. Overnight polysomnography (PSG) was performed with continuous BP monitoring. Subjects were assigned to groups according to their obstructive apnea-hypopnea index (OAHI): primary snoring (PS) (OAHI ≤1event/h), mild OSA (OAHI>1- ≤5events/h) and moderate/severe (MS) OSA (OAHI>5events/h). BRS and HPD were calculated using cross spectral analysis and BPV using power spectral analysis. Results: Subjects with OSA had significantly lower BRS (p<.05 for both) and a longer HPD (PS and MS OSA, p<.01; mild OSA, p<.05) response to spontaneous BP changes compared with controls. In all frequencies of BPV, the MS group had higher power compared with the control and PS groups (low frequency [LF], p<.05; high frequency [HF], p<.001). Conclusions: Our study demonstrates reduced BRS, longer HPD, and increased BPV in subjects with OSA compared to controls. This finding suggests that children with OSA have altered baroreflex function. Longitudinal studies are required to ascertain if this dampening of the normal baroreflex response can be reversed with treatment.
    Sleep Medicine 06/2013; 14(9). DOI:10.1016/j.sleep.2013.01.015 · 3.15 Impact Factor
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    • "Heart rate variability (HRV) Balachandran et al. (2012), Bianchi et al. (2010), Aydin et al. (2004), Kesek et al. (2009), Choi et al. (2011), Cheng et al. (2011), Gapelyuk et al. (2011) Reduced HRV is found in OSA patients, and is "
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    ABSTRACT: Sleep is involved in the regulation of major organ functions in the human body, and disruption of sleep potentially can elicit organ dysfunction. Obstructive sleep apnea (OSA) is the most prevalent sleep disorder of breathing in adults and children, and its manifestations reflect the interactions between intermittent hypoxia, intermittent hypercapnia, increased intra-thoracic pressure swings, and sleep fragmentation, as elicited by the episodic changes in upper airway resistance during sleep. The sympathetic nervous system is an important modulator of the cardiovascular, immune, endocrine and metabolic systems, and alterations in autonomic activity may lead to metabolic imbalance and organ dysfunction. Here we review how OSA and its constitutive components can lead to perturbation of the autonomic nervous system in general, and to altered regulation of catecholamines, both of which then playing an important role in some of the mechanisms underlying OSA-induced morbidities.
    Frontiers in Neurology 01/2012; 3:7. DOI:10.3389/fneur.2012.00007
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    ABSTRACT: Sleep apnea is the most common sleep disturbance and it is an important risk factor for cardiovascular disorders. Its detection relies on a polysomnography, a combination of diverse exams. In order to detect changes due to sleep disturbances such as sleep apnea occurrences, without the need of combined recordings, we mainly analyze systolic blood pressure signals (maximal blood pressure value of each beat to beat interval). Nonstationarities in the data are uncovered by a segmentation procedure, which provides local quantities that are correlated to apnea-hypopnea events. Those quantities are the average length and average variance of stationary patches. By comparing them to an apnea score previously obtained by polysomnographic exams, we propose an apnea quantifier based on blood pressure signal. This furnishes an alternative procedure for the detection of apnea based on a single time series, with an accuracy of 82%.
    PLoS ONE 06/2014; 9(9). DOI:10.1371/journal.pone.0107581 · 3.23 Impact Factor
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