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Random frequency squat-stands Accepted Version.pdf (194.71 kB)

Random squat-stand maneuvers: a novel approach for assessment of dynamic cerebral autoregulation?

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posted on 2017-09-05, 14:52 authored by Sam C. Barnes, Naomi Ball, Victoria Joanna Haunton, Ronney B. Panerai, Thompson G. Robinson
BACKGROUND: Squat-stand maneuvers (SSM) have been used to assess dynamic cerebral autoregulation (dCA), but always at a fixed-frequency (FF). This study aimed to assess the use of random-frequency (RF) SSMs as a stimulus for measuring dCA, and to determine the reproducibility of FF and RFSSMs. METHOD: 29 healthy volunteers (19 male, mean age 23.0 [4.9] years) completed the study; 11 returned for a repeat visit (median 45 days). Heart rate, beat-to-beat blood pressure, middle cerebral artery (MCA) blood flow velocity, end-tidal CO2 and angle of the squat movement were measured. Subjects underwent four recordings: 5 minutes sitting; 5 minutes standing; FFSSMs (0.05Hz); RFSSMs. Subjects were asked to rate the degree of exertion experienced while performing these maneuvers. RESULTS: 29 subjects completed the protocol; 9 data sets were deemed unsuitable for further analysis. Mean ARI of 6.21 (1.04) while standing was significantly greater than during the SSMs (p<0.01); mean (SD) ARI during the FF and RFSSMs being 5.16 (1.43) and 5.37 (1.21), respectively. However, no significant difference was found between the ARI estimates from the two SSMs (p=0.856) or for each of the four recordings between the two visits (p=0.645). RFSSMs were found to be significantly less tiring than FFSSMs (p<0.01). CONCLUSION: RFSSMs are an effective and non-invasive method of assessing dCA. There is no difference in the ARI estimates in comparison with FFSSMs. While FFSSMs have been well tolerated previously, RFSSMs are preferred by healthy subjects and thus may be better tolerated by a patient population in a clinical setting.

History

Citation

Journal of Applied Physiology, 2017, in press

Author affiliation

/Organisation/COLLEGE OF MEDICINE, BIOLOGICAL SCIENCES AND PSYCHOLOGY/School of Medicine/Department of Cardiovascular Sciences

Version

  • AM (Accepted Manuscript)

Published in

Journal of Applied Physiology

Publisher

American Physiological Society

issn

8750-7587

eissn

1522-1601

Copyright date

2017

Available date

2018-06-22

Publisher version

http://jap.physiology.org/content/early/2017/06/22/japplphysiol.00316.2017

Notes

The file associated with this record is under embargo until 12 months after publication, in accordance with the publisher's self-archiving policy. The full text may be available through the publisher links provided above.

Language

en

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