Abstract
In obstructive sleep apnea syndrome (OSA) the periodic reduction or cessation of breathing due to narrowing or occlusion of the upper airway during sleep leads to an impaired cerebral vascular autoregulation that is associated with an increased cardiovascular risk, including stroke. Continuous positive airways pressure (CPAP) therapy at night is the most effective treatment for OSA and has been shown to reduce the cardiovascular risk in OSA patients. However, there is no suitable bedside monitoring method evaluating the recovery of cerebral hemodynamics during CPAP therapy. Near-infrared spectroscopy (NIRS) is ideally suited for non-invasive monitoring the cerebral hemodynamics during sleep due to its properties of local measurement, totally safe application and good tolerance to motion. In this pilot study, we monitored cerebral hemodynamics during standard CPAP therapy at night in three patients with severe OSA using NIRS. We found periodic oscillations in HbO2, HHb, tissue oxygenation index (TOI) and blood volume (BV) associated with periodic apnea events without CPAP in all OSA patients. These oscillations were eliminated under the optimal CPAP pressures in all patients. These results suggested that the recovery of cerebral hemodynamics impaired by apnea events can be evaluated by bedside NIRS measurements in real time during all night CPAP therapy. NIRS is a useful bedside monitoring tool to evaluate the treatment efficacy of CPAP therapy in patients with OSA.
Highlights
Obstructive sleep apnea syndrome (OSA) is the periodic reduction or cessation of breathing due to narrowing or occlusion of the upper airway during sleep.[1,2] The main consequences of OSA are daytime symptoms and increased cardiovascular risks including hypertension, ischaemic heart disease and stroke.[3,4,5] In healthy humans, the cerebral blood °ow (BF) should stay approximately constant when blood pressure varies, and adapt to changes in energy consumption and carbon dioxide and oxygen levels in the blood, and other factors
It has been well known that impairment of cerebral autoregulation mechanism involved in OSA contributes to the higher risk of stroke in OSA patients.[8,9]
Note: SD: standard deviation, BV: blood volume, tissue oxygenation index (TOI): tissue oxygen index, BV, HbO2 and HHb changes are expressed in arbitrary units (A.U.), as the mean value ofrst 60-s measurements was set at 0. In this pilot study on three patients with OSA, we found that the cerebral hemodynamic oscillations induced by apnea events can be e®ectively eliminated by Continuous positive airways pressure (CPAP) pressures
Summary
Obstructive sleep apnea syndrome (OSA) is the periodic reduction (hypopnea) or cessation (apnea) of breathing due to narrowing or occlusion of the upper airway during sleep.[1,2] The main consequences of OSA are daytime symptoms and increased cardiovascular risks including hypertension, ischaemic heart disease and stroke.[3,4,5] In healthy humans, the cerebral blood °ow (BF) should stay approximately constant when blood pressure varies, and adapt to changes in energy consumption and carbon dioxide and oxygen levels in the blood, and other factors This regulation of BF is achieved primarily by arterioles dilating and contracting (vasomotion), under the in°uence of multiple complex physiological control systems which are termed as cerebral autoregulation mechanism.[6,7] Cerebral autoregulation is often interpreted as encompassing the widereld of cerebral BF regulation, including neurovascular coupling and other aspects of cerebral hemodynamics. It has been well known that impairment of cerebral autoregulation mechanism involved in OSA contributes to the higher risk of stroke in OSA patients.[8,9]
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
