Changes in cerebral oxygenation associated with arousal during sleep in old & young adults

2.50
Hdl Handle:
http://hdl.handle.net/10755/165991
Category:
Abstract
Type:
Presentation
Title:
Changes in cerebral oxygenation associated with arousal during sleep in old & young adults
Author(s):
Carlson, Barbara
Author Details:
Barbara Carlson, University of North Carolina at Chapel Hill, Biobehavioral Laboratory, School of Nursing, Chapel Hill, North Carolina, USA, email: bcarlson@email.unc.edu
Abstract:
Introduction: Sleep represents a period of increased risk for hypoxia that may impair brain function. Arousal is an important protective response to minimize cerebral hypoxia during sleep. Studies using methods of cerebral imaging (PET & fMRI) show that in normal awake subjects, brain activity significantly increases regional cerebral blood flow. We hypothesize that older adults with low cerebral oxidative reserves are more likely to have impaired oxidative responses to cerebral challenge during sleep and are at greater risk for hypoxic injury to the brain. The specific aims are to determine if noninvasive cerebral oximetry can detect changes in regional cerebral hemoglobin oxygen saturation (rcSO2) induced by arousal challenge and to compare differences in rcSO2 and oxygen utilization in a sample of young and old adults. Methods: We monitored 10 older (65-84, 5M, 8 rt-handed) and 10 younger adults (21-39, 4M, 10 rt-handed) at a General Clinical Research Center. We used a standard protocol with a 6-hour period of sedentary activity followed by a 2-hour sleep-nap (10pm-12am). Right- and left-sided rcSO2 and blood volume indices (BVI) were measured with the INVOS 4100 (Somanetics Inc, Akron OH). Standard methods were used to record sleep and arousals (central and posterior EEG, 2-channel EOG, submental EMG), respiratory movements (Respitrace, AMI, Ardlsey NY), and arterial oxygen saturation (Nellcor, San Diego, CA). Signals were stored to computer using Windaq Waveform Acquisition Software at 250s/s, divided into 5-minute segments for analysis. Oxygen utilization was examined by changes of rcSO2 and BVI from baseline. Results: Older adults took longer to go to sleep, but once asleep, spent more time in SWS and had fewer arousals than younger adults. All subjects had normal SaO2 values (95-97%). Regional cerebral hemoglobin saturation ranged from 56-77% in older and 72-97% in younger adults. Older adults had greater differences in rt- and lt-sided rcSO2 (3-5%) than younger adults (1-2%). The older adults had lower rcSO2 values than the younger adults at the start (rt: xold=60.4% xyoung =72.7%; lt: xold =64.7%; xyoung=71.4%). Once asleep, older adults rcSO2 values decreased (xright= -6.8%, xleft= -1.5%) while rcSO2 values in the younger adults tended to increase (xright= 2.3%, xleft= .1%). Arousals in older adults were associated with a decrease in both rcSO2 (xright= -3.8% xleft= -3.7%) and BVI (xright= -2.5u; xleft= -.47u). Arousals in young adults were associated with an increase in both rcSO2 (xright=2.4% xleft=3.2%) and BVI (xright=-1.5u; xleft=2.1u). Conclusions: Older adults have lower rcSO2 values at sleep onset and show significant decreases in rcSO2 during sleep as compared to younger subjects. Older adults showed a significant decrease in rcSO2 and BVI in response to arousal. These results suggest that older adults with lower oxygen reserves and impaired arousal response may be at greater risk for hypoxic injury during sleep. Finally, cerebral oximetry is a potentially useful method for monitoring regional cerebral oxygen changes during sleep. Future studies will examine how patterns of rcSO2 and BVI responses during arousal relate to impairment in daytime cognitive and physical function.
Repository Posting Date:
27-Oct-2011
Date of Publication:
27-Oct-2011
Conference Host:
Southern Nursing Research Society
Note:
This is an abstract-only submission. If the author has submitted a full-text item based on this abstract, you may find it by browsing the Virginia Henderson Global Nursing e-Repository by author. If author contact information is available in this abstract, please feel free to contact him or her with your queries regarding this submission. Alternatively, please contact the conference host, journal, or publisher (according to the circumstance) for further details regarding this item. If a citation is listed in this record, the item has been published and is available via open-access avenues or a journal/database subscription. Contact your library for assistance in obtaining the as-published article.

Full metadata record

DC FieldValue Language
dc.type.categoryAbstracten_US
dc.typePresentationen_GB
dc.titleChanges in cerebral oxygenation associated with arousal during sleep in old & young adultsen_GB
dc.contributor.authorCarlson, Barbaraen_US
dc.author.detailsBarbara Carlson, University of North Carolina at Chapel Hill, Biobehavioral Laboratory, School of Nursing, Chapel Hill, North Carolina, USA, email: bcarlson@email.unc.eduen_US
dc.identifier.urihttp://hdl.handle.net/10755/165991-
dc.description.abstractIntroduction: Sleep represents a period of increased risk for hypoxia that may impair brain function. Arousal is an important protective response to minimize cerebral hypoxia during sleep. Studies using methods of cerebral imaging (PET & fMRI) show that in normal awake subjects, brain activity significantly increases regional cerebral blood flow. We hypothesize that older adults with low cerebral oxidative reserves are more likely to have impaired oxidative responses to cerebral challenge during sleep and are at greater risk for hypoxic injury to the brain. The specific aims are to determine if noninvasive cerebral oximetry can detect changes in regional cerebral hemoglobin oxygen saturation (rcSO2) induced by arousal challenge and to compare differences in rcSO2 and oxygen utilization in a sample of young and old adults. Methods: We monitored 10 older (65-84, 5M, 8 rt-handed) and 10 younger adults (21-39, 4M, 10 rt-handed) at a General Clinical Research Center. We used a standard protocol with a 6-hour period of sedentary activity followed by a 2-hour sleep-nap (10pm-12am). Right- and left-sided rcSO2 and blood volume indices (BVI) were measured with the INVOS 4100 (Somanetics Inc, Akron OH). Standard methods were used to record sleep and arousals (central and posterior EEG, 2-channel EOG, submental EMG), respiratory movements (Respitrace, AMI, Ardlsey NY), and arterial oxygen saturation (Nellcor, San Diego, CA). Signals were stored to computer using Windaq Waveform Acquisition Software at 250s/s, divided into 5-minute segments for analysis. Oxygen utilization was examined by changes of rcSO2 and BVI from baseline. Results: Older adults took longer to go to sleep, but once asleep, spent more time in SWS and had fewer arousals than younger adults. All subjects had normal SaO2 values (95-97%). Regional cerebral hemoglobin saturation ranged from 56-77% in older and 72-97% in younger adults. Older adults had greater differences in rt- and lt-sided rcSO2 (3-5%) than younger adults (1-2%). The older adults had lower rcSO2 values than the younger adults at the start (rt: xold=60.4% xyoung =72.7%; lt: xold =64.7%; xyoung=71.4%). Once asleep, older adults rcSO2 values decreased (xright= -6.8%, xleft= -1.5%) while rcSO2 values in the younger adults tended to increase (xright= 2.3%, xleft= .1%). Arousals in older adults were associated with a decrease in both rcSO2 (xright= -3.8% xleft= -3.7%) and BVI (xright= -2.5u; xleft= -.47u). Arousals in young adults were associated with an increase in both rcSO2 (xright=2.4% xleft=3.2%) and BVI (xright=-1.5u; xleft=2.1u). Conclusions: Older adults have lower rcSO2 values at sleep onset and show significant decreases in rcSO2 during sleep as compared to younger subjects. Older adults showed a significant decrease in rcSO2 and BVI in response to arousal. These results suggest that older adults with lower oxygen reserves and impaired arousal response may be at greater risk for hypoxic injury during sleep. Finally, cerebral oximetry is a potentially useful method for monitoring regional cerebral oxygen changes during sleep. Future studies will examine how patterns of rcSO2 and BVI responses during arousal relate to impairment in daytime cognitive and physical function.en_GB
dc.date.available2011-10-27T14:37:59Z-
dc.date.issued2011-10-27en_GB
dc.date.accessioned2011-10-27T14:37:59Z-
dc.conference.hostSouthern Nursing Research Societyen_US
dc.description.noteThis is an abstract-only submission. If the author has submitted a full-text item based on this abstract, you may find it by browsing the Virginia Henderson Global Nursing e-Repository by author. If author contact information is available in this abstract, please feel free to contact him or her with your queries regarding this submission. Alternatively, please contact the conference host, journal, or publisher (according to the circumstance) for further details regarding this item. If a citation is listed in this record, the item has been published and is available via open-access avenues or a journal/database subscription. Contact your library for assistance in obtaining the as-published article.-
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