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Lam et al Physiological Reports 2018.pdf (1.27 MB)

Does gradual change in head positioning affect cerebrovascular physiology?

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posted on 2018-03-27, 14:38 authored by Man Y Lam, Victoria J Haunton, Thompson G Robinson, Ronney Panerai
We studied cerebral blood velocity (CBV), and associated hemodynamic parameters during gradual changes in head positioning in a nonstroke group. CBV (transcranial Doppler ultrasound), beat-to-beat blood pressure (BP, Finometer), and end-tidal carbon dioxide (ETCO2, capnography) were recorded between lying flat (0°) and sitting up (30°) head positions, in 18 volunteers (10 female, mean age, 57 ± 16 years), at two visits (12 ± 8 days). A significant reduction was found between 5-min FLAT (0°) and 5-min SIT (30°) positions in CBV (visit 1: 4.5 ± 3.3%, P = 0.006; visit 2: 4.1 ± 3.5%, P = 0.003), critical closing pressure (CrCP; visit 1: 15.5 ± 14.0%, P = 0.0002; visit 2: 14.1 ± 7.8%, P = 0.009) and BP (visit 1: 8.3 ± 7.4%, P = 0.001; visit 2: 11.0 ± 11.3%, P < 0.001). For 5 min segments of data, the autoregulation index and other hemodynamic parameters did not show differences either due to head position or visit. For 30 sec time intervals, significant differences were observed in the following: (BP, P < 0.001; dominant hemisphere (DH) CBV, P < 0.005; nondominant hemisphere (NDH) CBV, P < 0.005; DH CrCP, P < 0.001; NDH CrCP, P < 0.001; DH resistance area product (RAP), P = 0.002; NDH RAP, P = 0.033). Significant static changes in BP, CBV and CrCP, and large transient changes in key hemodynamic parameters occur during 0° to 30°, and vice versa, with reproducible results. Further studies are needed following acute ischemic stroke to determine if a similar responses is present.

History

Citation

Physiological Reports, 2018, 6 (3), e13603

Author affiliation

/Organisation/COLLEGE OF LIFE SCIENCES/School of Medicine/Department of Cardiovascular Sciences

Version

  • VoR (Version of Record)

Published in

Physiological Reports

Publisher

Wiley Open Access for The Physiological Society and the American Physiological Society

eissn

2051-817X

Acceptance date

2017-12-29

Copyright date

2018

Available date

2018-03-27

Publisher version

https://physoc.onlinelibrary.wiley.com/doi/10.14814/phy2.13603

Language

en

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