Reproducibility of the simple cerebrovascular breath hold responses measured using transcranial color-coded doppler sonography?




Lauzon, Jayda

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Aging is a primary determinant of cerebrovascular dysfunction, often marked by poor cerebrovascular reactivity to carbon dioxide. Traditional transcranial doppler ultrasound can measure cerebral artery CO2 reactivity, but is unable to provide volumetric quantification, because it can not image blood vessel diameter. In contrast, transcranial color coded duplex ultrasound (TCCS) provides volumetric hemodynamic measures that include velocity and diameter. Thus, using TCCS to insonate the middle cerebral artery (MCA) during a simple breath hold response test, we attempted to quantify if reliable volumetric MCA CO2 reactivity measures were achievable. We hypothesized that measuring volumetric, rather than velocity only reactivity would not impair reproducibility outcomes. Six healthy adults (29+-10), on visited the CHEERS laboratory and completed a breathhold response protocol on two separate visits (~24-hrs between visits). Diameter, velocity and blood flow were collected at rest, during 30-seconds of hyperventilation, 30-seconds of apneac breathing, and 30-seconds of recovery breathing. Between day resting MCA measures were not different, nor were MCA responses different during hyperventilation, breath hold, or recovery breathing. Collectively, TCCS is a reliable approach to measuring dynamic volumetric MCA responses during BHR, and future studies should incorporate volumetric hemodynamics assessments.



reproducibility, cerebrovascular health, hypercapnic, hypocapnia, normocapnic, breath hold, vasodilation, cerebral blood flow, middle cerebral artery, transcranial doppler, diameter, velocity