Near-infrared spectrophotometry determined brain oxygenation during fainting

During orthostatic hypotension we evaluated whether presyncopal symptoms relate to a reduced brain oxygenation. Nine subjects performed 50° head‐up tilt for 1 h and eight subjects were followed during 2 h of supine rest and during 1 h of 10° head‐down tilt. Cerebral perfusion was assessed by transcr...

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Bibliographic Details
Published in:Acta physiologica Scandinavica 1998-03, Vol.162 (4), p.501-507
Main Authors: MADSEN, P, POTT, F, OLSEN, S. B, NIELSEN, H. B, BURCEV, I, SECHER, N. H
Format: Article
Language:English
Subjects:
Adult
Biological and medical sciences
Blood Flow Velocity - physiology
Blood Pressure
Brain - blood supply
Brain - metabolism
central venous pressure
Cerebral Arteries - physiology
cerebral blood flow
electrical impedance
Female
Head-Down Tilt - physiology
Headache. Facial pains. Syncopes. Epilepsia. Intracranial hypertension. Brain oedema. Cerebral palsy
Hemodynamics - physiology
Humans
hypotension
Male
Medical sciences
Middle Aged
near-infrared spectroscopy
Nervous system (semeiology, syndromes)
Neurology
Oxygen - blood
Oxygen Consumption
Space life sciences
Spectrophotometry, Infrared - methods
Syncope - metabolism
Tilt-Table Test - methods
transcranial Doppler
vaso-vagal syncope
venous oxygen saturation
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Summary:During orthostatic hypotension we evaluated whether presyncopal symptoms relate to a reduced brain oxygenation. Nine subjects performed 50° head‐up tilt for 1 h and eight subjects were followed during 2 h of supine rest and during 1 h of 10° head‐down tilt. Cerebral perfusion was assessed by transcranial Doppler determined middle cerebral artery blood velocity (MCA vmean), while brain blood oxygenation was assessed by near‐infrared spectrophotometry determined concentration changes for oxygenated (ΔHbO2) and deoxygenated haemoglobin and brain cell oxygenation by the oxidized cytochrome c concentration (ΔCytO2). During head‐up tilt, six volunteers developed presyncopal symptoms and mean arterial pressure (88 (78–103) to 68 (57–79) mmHg; median and range), heart rate (96 (72–111) to 65 (50–107) beats min−1), MCA vmean (59 (51–82) to 41 (29–56) cm s−1), ΔHbO2 (by −5.3 (−3.0 to −14.8) μmol l−1) and ΔCytO2 were reduced (by −0.2 (−0.1 to −0.4) μmol l−1; P 
ISSN:0001-6772
1365-201X
DOI:10.1046/j.1365-201X.1998.0308f.x