Improvement of Brain Tissue Oxygenation by Inhalation of Carbogen

TY - JOUR

T1 - Improvement of Brain Tissue Oxygenation by Inhalation of Carbogen

AU - Ashkanian, M.

AU - Borghammer, P.

AU - Gjedde, A.

AU - Ostergaard, L.

AU - Vafaee, M.

N1 - Keywords: Adult; Aged; Blood Flow Velocity; Blood Gas Analysis; Brain; Brain Chemistry; Brain Mapping; Carbon Dioxide; Cerebrovascular Circulation; Female; Humans; Inhalation; Magnetic Resonance Imaging; Male; Middle Aged; Oxygen; Oxygen Radioisotopes; Positron-Emission Tomography; Radiation-Sensitizing Agents

PY - 2008

Y1 - 2008

N2 - Hyperoxic therapy for cerebral ischemia is suspected to reduce cerebral blood flow (CBF), due to the vasoconstrictive effect of oxygen on cerebral arterioles. We hypothesized that vasodilation predominates when 5% CO(2) is added to the inhaled oxygen (carbogen). Therefore, we used positron emission tomography (PET) to measure CBF and cerebral metabolic rate of oxygen (CMRO(2)) during inhalation of test gases (O(2), CO(2), carbogen and atmospheric air) in 10 healthy volunteers. Arterial blood gases were recorded during administration of each gas. The data were analyzed with volume-of-interest and voxel-based statistical methods. Inhalation of CO(2) or carbogen significantly increased global CBF, whereas pure oxygen decreased global CBF. The CMRO(2) generally remained unchanged, except in white matter during oxygen inhalation relative to condition of atmospheric air inhalation. The volume-of-interest results were confirmed by statistical cluster analysis. Oxygen and carbogen were equally potent in increasing oxygen saturation of arterial blood (Sa(O2)). The present data demonstrate that inhalation of carbogen increases both CBF and Sa(O2) in healthy adults. In conclusion we speculate that carbogen inhalation is sufficient for optimal oxygenation of healthy brain tissue, whereas carbogen induces concomitant increases of CBF and Sa(O2).

AB - Hyperoxic therapy for cerebral ischemia is suspected to reduce cerebral blood flow (CBF), due to the vasoconstrictive effect of oxygen on cerebral arterioles. We hypothesized that vasodilation predominates when 5% CO(2) is added to the inhaled oxygen (carbogen). Therefore, we used positron emission tomography (PET) to measure CBF and cerebral metabolic rate of oxygen (CMRO(2)) during inhalation of test gases (O(2), CO(2), carbogen and atmospheric air) in 10 healthy volunteers. Arterial blood gases were recorded during administration of each gas. The data were analyzed with volume-of-interest and voxel-based statistical methods. Inhalation of CO(2) or carbogen significantly increased global CBF, whereas pure oxygen decreased global CBF. The CMRO(2) generally remained unchanged, except in white matter during oxygen inhalation relative to condition of atmospheric air inhalation. The volume-of-interest results were confirmed by statistical cluster analysis. Oxygen and carbogen were equally potent in increasing oxygen saturation of arterial blood (Sa(O2)). The present data demonstrate that inhalation of carbogen increases both CBF and Sa(O2) in healthy adults. In conclusion we speculate that carbogen inhalation is sufficient for optimal oxygenation of healthy brain tissue, whereas carbogen induces concomitant increases of CBF and Sa(O2).

U2 - 10.1016/j.neuroscience.2008.08.016

DO - 10.1016/j.neuroscience.2008.08.016

M3 - Journal article

C2 - 18786619

SN - 0306-4522

VL - 156

SP - 932

EP - 938

JO - Neuroscience

JF - Neuroscience

IS - 4

ER -