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Updated: Aug 30, 2026

MRI Mapping of Cerebrovascular Reactivity via Gas Inhalation Challenges
Published on: December 17, 2014
Cerebrovascular response to acute metabolic acidosis in humans
Marjo van de Ven1, Willy N Colier, Bregina T Kersten
1Department of Pulmonology, Rijnstate Hospital Arnhem, PO 9555, 6800 TA Arnhem, The Netherlands.
Objectives:
Evaluation of the cerebrovascular response (delta CBV/delta PaCO2) during baseline metabolic conditions and acute metabolic acidosis.
Methods:
15 healthy subjects, 5 m, 10 f, 56 +/- 10 yrs were investigated. For acidification, NH4Cl was given orally. CBV was measured using Near Infrared Spectroscopy (OXYMON) during normo-, hyper- and hypocapnia.
Results:
Acute metabolic acidosis was realised: mean delta BE -2.7 mEq.L-1 (p < 0.001) with mean delta PaCO2 -0.2 kPa (p < 0.01). During normo-, hyper- and hypocapnia, CBV values of 3.51, 4.82 and 2.55 mL.100 g-1 were calculated during baseline metabolic conditions and 3.70, 4.86 and 2.63 mL.100 g-1 during acute metabolic acidosis. The CBV/PaCO2 response showed a hockeystick configuration with the point of infliction around normocapnia. delta CBV/delta PaCO2 reactivity from normo- to hypercapnia and from normo- to hypocapnia was calculated; no significant differences in delta CBV/delta PaCO2 were found in both metabolic conditions.
Conclusion:
Cerebrovascular reactivity to CO2 does not alter during acute metabolic acidosis.
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