Is dynamic cerebral autoregulation measurement using transcranial Doppler ultrasound reproducible in the presence of high concentration oxygen and carbon dioxide? Jatinder S. Minhas Nazia F. Syed Victoria J. Haunton Ronney B. Panerai Thompson G. Robinson Amit K. Mistri 2381/39823 https://figshare.le.ac.uk/articles/journal_contribution/Is_dynamic_cerebral_autoregulation_measurement_using_transcranial_Doppler_ultrasound_reproducible_in_the_presence_of_high_concentration_oxygen_and_carbon_dioxide_/10233401 Reliability of cerebral blood flow velocity (CBFV) and dynamic cerebral autoregulation estimates (expressed as autoregulation index: ARI) using spontaneous fluctuations in blood pressure (BP) has been demonstrated. However, reliability during co-administration of O2 and CO2 is unknown. Bilateral CBFV (using transcranial Doppler), BP and RR interval recordings were performed in healthy volunteers (seven males, four females, age: 54  ±  10 years) on two occasions over 9  ±  4 d. Four 5 min recordings were made whilst breathing air (A), then 5%CO2 (C), 80%O2 (O) and mixed O2  +  CO2 (M), in random order. CBFV was recorded; ARI was calculated using transfer function analysis. Precision was quantified as within-visit standard error of measurement (SEM) and the coefficient of variation (CV). CBFV and ARI estimates with A (SEM: 3.85 & 0.87; CV: 7.5% & 17.8%, respectively) were comparable to a previous reproducibility study. The SEM and CV with C and O were similar, though higher values were noted with M; Bland-Altman plots indicated no significant bias across all gases for CBFV and ARI (bias  <0.06 cm s(-1) and  <0.05, respectively). Thus, transcranial-Doppler-ultrasound-estimated CBFV and ARI during inhalation of O2 and CO2 have acceptable levels of reproducibility and can be used to study the effect of these gases on cerebral haemodynamics. 2017-05-19 10:51:31 Adult Aged Air Carbon Dioxide Cerebrovascular Circulation Diagnostic Techniques, Cardiovascular Female Fingers Heart Rate Homeostasis Humans Male Middle Aged Neurophysiological Monitoring Oxygen Reproducibility of Results Ultrasonography, Doppler, Transcranial