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Noninvasive assessment of CO2-induced cerebral vasomotor response in normal individuals and patients with internal carotid artery occlusions
- Source :
- Stroke. 19:963-969
- Publication Year :
- 1988
- Publisher :
- Ovid Technologies (Wolters Kluwer Health), 1988.
-
Abstract
- To evaluate the CO2-induced vasomotor reactivity of the cerebral vasculature, relative changes of blood flow velocity within the middle cerebral artery were measured by transcranial Doppler ultrasonography during normocapnia and various degrees of hypercapnia and hypocapnia. We studied 40 normal individuals and 40 patients with unilateral and 15 patients with bilateral internal carotid artery occlusions. When blood flow velocity changes as percent of normocapnic values were plotted against end-tidal CO2 volume percent, a biasymptotic curve (a tangent-hyperbolic function) gave the best fit of the scattergram. The distance between the upper and lower asymptotes was defined as cerebral vasomotor reactivity. In the normal individuals, mean +/- SD vasomotor reactivity was 85.63 +/- 15.96%. In patients with internal carotid artery occlusions, vasomotor reactivity was significantly lower than normal on both the occluded (mean 45.2%, median 50.4%; p less than 0.0001) and the nonoccluded (mean +/- SD 67.7 + 13.3%, p less than 0.01) sides in the unilateral group and on both sides (mean +/- SD 36.6 +/- 15.9% and 44.9 +/- 24.6%, p less than 0.0001) in the bilateral group. The difference between vasomotor reactivity for symptomatic and asymptomatic unilateral occlusions was also highly significant (mean 37.6% and 62.9%, p less than 0.006). Vasomotor reactivity was also significantly lower in patients with low-flow infarctions on computed tomography than in patients with normal scans (mean +/- SD 36.7 +/- 25% and 60.2 +/- 16.9%, p less than 0.008). A striking association of low-flow infarctions, ischemic ophthalmopathy, and hypostatic transient ischemic attacks was found with vasomotor reactivities of less than 34% or even paradoxical reactions.(ABSTRACT TRUNCATED AT 250 WORDS)
- Subjects :
- Adult
Carotid Artery Diseases
Male
Arterial Occlusive Diseases
Asymptomatic
Cerebral circulation
Hypocapnia
Reference Values
medicine.artery
medicine
Humans
Normocapnia
Aged
Ultrasonography
Aged, 80 and over
Advanced and Specialized Nursing
Vasomotor
business.industry
Carbon Dioxide
Middle Aged
medicine.disease
Cerebrovascular Circulation
Anesthesia
Middle cerebral artery
Female
Neurology (clinical)
Internal carotid artery
medicine.symptom
Cardiology and Cardiovascular Medicine
business
Hypercapnia
Carotid Artery, Internal
Subjects
Details
- ISSN :
- 15244628 and 00392499
- Volume :
- 19
- Database :
- OpenAIRE
- Journal :
- Stroke
- Accession number :
- edsair.doi.dedup.....fe425c7f1bd9cc0244be6e128835a5ff