Cerebral blood flow velocity during simultaneous changes in mean arterial pressure and cardiac output in healthy volunteers.

Content Provider	Europe PMC
Author	Lie, Sole Lindvåg Hisdal, Jonny Høiseth, Lars Øivind
Abstract	PurposeCerebral blood flow (CBF) needs to be precisely controlled to maintain brain functions. While previously believed to be autoregulated and near constant over a wide blood pressure range, CBF is now understood as more pressure passive. However, there are still questions regarding the integrated nature of CBF regulation and more specifically the role of cardiac output. Our aim was, therefore, to explore the effects of MAP and cardiac output on CBF in a combined model of reduced preload and increased afterload.Method16 healthy volunteers were exposed to combinations of different levels of simultaneous lower body negative pressure and isometric hand grip. We measured blood velocity in the middle cerebral artery (MCAV) and internal carotid artery (ICAV) by Doppler ultrasound, and cerebral oxygen saturation (ScO2) by near-infrared spectroscopy, as surrogates for CBF. The effect of changes in MAP and cardiac output on CBF was estimated with mixed multiple regression.ResultBoth MAP and cardiac output had independent effects on MCAV, ICAV and ScO2. For ICAV and ScO2 there was also a statistically significant interaction effect between MAP and cardiac output. The estimated effect of a change of 10 mmHg in MAP on MCAV was 3.11 cm/s (95% CI 2.51–3.71, P < 0.001), and the effect of a change of 1 L/min in cardiac output was 3.41 cm/s (95% CI 2.82–4.00, P < 0.001).ConclusionThe present study indicates that during reductions in cardiac output, both MAP and cardiac output have independent effects on CBF.Supplementary InformationThe online version contains supplementary material available at 10.1007/s00421-021-04693-6.
Related Links	https://europepmc.org/backend/ptpmcrender.fcgi?accid=PMC8260418&blobtype=pdf
ISSN	14396319
Journal	European Journal of Applied Physiology [Eur J Appl Physiol]
Volume Number	121
DOI	10.1007/s00421-021-04693-6
PubMed Central reference number	PMC8260418
Issue Number	8
PubMed reference number	33890157
e-ISSN	14396327
Language	English
Publisher	Springer Berlin Heidelberg
Publisher Date	2021-04-22
Publisher Place	Berlin/Heidelberg
Access Restriction	Open
Rights License	Open AccessThis article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons licence, and indicate if changes were made. The images or other third party material in this article are included in the article's Creative Commons licence, unless indicated otherwise in a credit line to the material. If material is not included in the article's Creative Commons licence and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this licence, visit http://creativecommons.org/licenses/by/4.0/. © The Author(s) 2021
Subject Keyword	Blood pressure Cardiac output Cerebrovascular circulation Hypovolemia Volunteers
Content Type	Text
Resource Type	Article
Subject	Orthopedics and Sports Medicine Physiology (medical) Public Health, Environmental and Occupational Health Sports Science