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Daytime sympathetic hyperactivity in OSAS is related to excessive daytime sleepiness
Author(s) -
DONADIO VINCENZO,
LIGUORI ROCCO,
VETRUGNO ROBERTO,
CONTIN MANUELA,
ELAM MIKAEL,
WALLIN B. GUNNAR,
KARLSSON TOMAS,
BUGIARDINI ENRICO,
BARUZZI AGOSTINO,
MONTAGNA PASQUALE
Publication year - 2007
Publication title -
journal of sleep research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.297
H-Index - 117
eISSN - 1365-2869
pISSN - 0962-1105
DOI - 10.1111/j.1365-2869.2007.00602.x
Subject(s) - medicine , microneurography , polysomnography , excessive daytime sleepiness , blood pressure , ambulatory blood pressure , baroreflex , daytime , anesthesia , epworth sleepiness scale , cardiology , physical therapy , heart rate , apnea , sleep disorder , insomnia , atmospheric sciences , psychiatry , geology
Summary The aim of this study was to investigate the relationships among sympathetic hyperactivity, excessive daytime sleepiness (EDS) and hypertension in obstructive sleep apnoea syndrome (OSAS). Ten newly diagnosed OSAS patients with untreated EDS and daytime hypertension underwent polysomnography (PSG) and daytime measurements of plasma noradrenaline (NA), ambulatory blood pressure (BP), muscle sympathetic nerve activity (MSNA) by microneurography and objective assessment of EDS before and during 6 months of compliance‐monitored continuous positive airway pressure (CPAP) treatment. One month after the start of CPAP, BP, MSNA and NA were significantly lowered, remaining lower than baseline also after 3 and 6 months of treatment. CPAP use caused a significant improvement of sleep structures, and reduced EDS. A statistical correlation analysis demonstrated that EDS was not correlated with sleep measures obtained from baseline PSG (% sleep stages, apnoea and arousal index, mean oxygen saturation value), whereas daytime sleepiness was significantly correlated with MSNA. Furthermore, MSNA and BP showed no correlation. Our data obtained from selected patients suggest that the mechanisms inducing EDS in OSAS are related to the degree of daytime sympathetic hyperactivity. Additionally, resting MSNA was unrelated to BP suggesting that factors other than adrenergic neural tone make a major contribution to OSAS‐related hypertension. The results obtained in this pilot study need, however, to be confirmed in a larger study involving more patients.