Cerebral vasomotor reactivity to carbon dioxide using the rebreathe technique: assessment of within-day and between-day repeatability
Date
2024-12-01
Journal Title
Journal ISSN
Volume Title
Publisher
American Journal of Physiology - Regulatory, Integrative and Comparative Physiology
Abstract
The cerebral vasodilator response to increased arterial carbon dioxide (CO2) concentration, termed cerebral vasomotor reactivity (CVMR), is used to assess cerebral vascular function. We sought to assess the within-day and between-day repeatability of CVMR to rebreathing-induced hypercapnia. Twelve healthy adults performed a within-day short interval protocol (17 ± 2 min between trials), ten performed a within-day long interval protocol (145 ± 16 min between trials), and seventeen performed a between-day protocol (5 ± 2 days between visits). Repeatability of the slope of the percent change in middle cerebral artery mean blood velocity (%MCAvmean) and cerebral vascular conductance index (%CVCi), to the change in partial pressure of end-tidal CO2 (PETCO2) between the two trials/days was assessed. Within-day short interval, %MCAvmean slope demonstrated fair to excellent repeatability (intraclass correlation, ICC = 0.92 [95% confidence interval 0.72–0.98]; P < 0.001) while %CVCi slope showed more variability (ICC = 0.84 [0.47–0.95]; P = 0.002]). Within-day long interval, %MCAvmean (ICC = 0.95 [0.80–0.99]) and %CVCi (ICC = 0.94 [0.71–0.99]) slopes showed good to excellent and fair to excellent repeatability respectively (P < 0.001 for both). For between-day trials, better repeatability was observed for %CVCi (ICC = 0.85 [0.57–0.95]; P < 0.001) compared with %MCAvmean (ICC = 0.76 [0.33–0.91]; P = 0.004) slope. These findings indicate repeatable within- and between-day CVMR responses to rebreathe-induced hypercapnia. However, a longer interval may be better for within-day repeat trials, particularly for CVCi measures.
Description
This article was originally published in American Journal of Physiology - Regulatory, Integrative and Comparative Physiology. The version of record is available at: https://doi.org/10.1152/ajpregu.00030.2024.
Copyright © 2024 the American Physiological Society.
This article will be embargoed until 12/1/2025.
Keywords
cerebral vascular reactivity, cerebrovascular function, middle cerebral artery blood velocity, rebreathing-induced hypercapnia, transcranial Doppler ultrasound
Citation
Nandadeva, Damsara, Rachel J. Skow, Zachary T. Martin, Jordan C. Patik, Ziba Taherzadeh, Alison Ortiz, Yungfei Kao, Paul J. Fadel, and R. Matthew Brothers. “Cerebral Vasomotor Reactivity to Carbon Dioxide Using the Rebreathe Technique: Assessment of within-Day and between-Day Repeatability.” American Journal of Physiology-Regulatory, Integrative and Comparative Physiology 327, no. 6 (December 1, 2024): R580–89. https://doi.org/10.1152/ajpregu.00030.2024.