Document Detail

Spontaneous fluctuations in the peripheral photoplethysmographic waveform: roles of arterial pressure and muscle sympathetic nerve activity.
MedLine Citation:
PMID:  22114133     Owner:  NLM     Status:  MEDLINE    
Assessment of spontaneous slow waves in the peripheral blood volume using the photoplethysmogram (PPG) has shown potential clinical value, but the physiological correlates of these fluctuations have not been fully elucidated. This study addressed the contribution of arterial pressure and muscle sympathetic nerve activity (MSNA) in beat-to-beat PPG variability in resting humans under spontaneous breathing conditions. Peripheral PPG waveforms were measured from the fingertip, earlobe, and toe in young and healthy individuals (n = 13), together with the arterial pressure waveform, electrocardiogram, respiration, and direct measurement of MSNA by microneurography. Cross-spectral coherence analysis revealed that among the PPG waveforms, low-frequency fluctuations (0.04-0.15 Hz) in the ear PPG had the highest coherence with arterial pressure (0.71 ± 0.15) and MSNA (0.44 ± 0.18, with a peak of 0.71 ± 0.16 at 0.10 ± 0.03 Hz). The normalized midfrequency powers (0.08-0.15 Hz), with an emphasis on the 0.1-Hz region, were positively correlated between MSNA and the ear PPG (r = 0.77, P = 0.002). Finger and toe PPGs had lower coherence with arterial pressure (0.35 ± 0.10 and 0.30 ± 0.11, respectively) and MSNA (0.33 ± 0.10 and 0.26 ± 0.10, respectively) in the LF band but displayed higher coherence between themselves (0.54 ± 0.09) compared with the ear (P < 0.001), which may suggest the dominance of regional vasomotor activities and a common sympathetic influence in the glabrous skin. These findings highlight the differential mechanisms governing PPG waveform fluctuations across different body sites. Spontaneous PPG variability in the ear includes a major contribution from arterial pressure and MSNA, which may provide a rationale for its clinical utility.
Gregory S H Chan; Azharuddin Fazalbhoy; Ingvars Birznieks; Vaughan G Macefield; Paul M Middleton; Nigel H Lovell
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Publication Detail:
Type:  Clinical Trial; Journal Article     Date:  2011-11-23
Journal Detail:
Title:  American journal of physiology. Heart and circulatory physiology     Volume:  302     ISSN:  1522-1539     ISO Abbreviation:  Am. J. Physiol. Heart Circ. Physiol.     Publication Date:  2012 Feb 
Date Detail:
Created Date:  2012-02-01     Completed Date:  2012-03-20     Revised Date:  2012-05-23    
Medline Journal Info:
Nlm Unique ID:  100901228     Medline TA:  Am J Physiol Heart Circ Physiol     Country:  United States    
Other Details:
Languages:  eng     Pagination:  H826-36     Citation Subset:  IM    
1School of Electrical Engineering and Telecommunications, University of New South Wales, Sydney, New South Wales.
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MeSH Terms
Blood Pressure / physiology*
Blood Volume / physiology*
Blood Volume Determination / methods,  standards
Fingers / blood supply
Linear Models
Muscle, Skeletal / blood supply*,  innervation*
Photoplethysmography / methods*,  standards
Reference Values
Sympathetic Nervous System / physiology*
Toes / blood supply
Young Adult

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine

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