|Appears in Collections:||Faculty of Health Sciences and Sport Journal Articles|
|Peer Review Status:||Refereed|
|Title:||The CO2 stimulus duration and steady-state time point used for data extraction alters the cerebrovascular reactivity outcome measure|
|Author(s):||Burley, Claire V|
Lucas, Rebekah A I
Whittaker, Anna C
Lucas, Samuel J E
|Citation:||Burley CV, Lucas RAI, Whittaker AC, Mullinger K & Lucas SJE (2020) The CO2 stimulus duration and steady-state time point used for data extraction alters the cerebrovascular reactivity outcome measure. Experimental Physiology, 105 (5), pp. 893-903. https://doi.org/10.1113/EP087883|
|Abstract:||Cerebrovascular reactivity to carbon dioxide (CVR) is a common functional test to assess brain vascular health, though conflicting age and fitness effects have been reported. Studies have used different CO 2 stimulus durations to induce CVR and extracted data from different time points for analysis. Therefore, this study examined whether these differences alter CVR and explain conflicting findings. Eighteen healthy volunteers (24 5 years) inhaled CO ± 2 for four stimulus durations (1, 2, 4 and 5 min) of 5% CO 2 (in air) via the open-circuit Douglas bag method, in a randomized order. CVR data were derived from transcranial Doppler (TCD) measures of middle cerebral artery blood velocity (MCAv), with concurrent ventilatory sensitivity to the CO 2 stimulus (̇ V E,CO 2). Repeated measures ANOVAs compared CVR and ̇ V E,CO 2 measures between stimulus durations and steady-state time points. An effect of stimulus duration was observed (P = 0.002, í µí¼ 2 = = 0.140), with 1 min (P 0.010) and 2 min (P < 0.001) differing from 4 min, and 2 min differing from 5 min (P = 0.019) durations. ̇ V E CO , 2 sensitivity increased ∼3-fold from 1 min to 4 and 5 min durations (P < 0.001, í µí¼ 2 = 0.485). CVRs calculated from different steady-state time points within each stimulus duration were different (P < 0.001, í µí¼ 2 = = 0.454), specifically for 4 min (P 0.001) and 5 min (P P < 0.001), but not 2 min stimulus durations (= 0.273). These findings demonstrate that methodological differences alter the CVR measure.|
|Rights:||This item has been embargoed for a period. During the embargo please use the Request a Copy feature at the foot of the Repository record to request a copy directly from the author. You can only request a copy if you wish to use this work for your own research or private study. This is the peer reviewed version of the following article: Burley, CV, Lucas, RAI, Whittaker, AC, Mullinger, K, Lucas, SJE. The CO2 stimulus duration and steady-state time point used for data extraction alters the cerebrovascular reactivity outcome measure. Experimental Physiology. 2020; 105: 893– 903, which has been published in final form at https://doi.org/10.1113/EP087883. This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for self-archiving.|
|accepted_article_feb_2020.pdf||Fulltext - Accepted Version||1.84 MB||Adobe PDF||Under Embargo until 2021-02-22 Request a copy|
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