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Updated: Jun 28, 2026

Functional Transcranial Doppler Ultrasound for Monitoring Cerebral Blood Flow
Published on: March 15, 2021
Different bispectral index values from both sides of the forehead in unilateral carotid artery stenosis
1Department of Anesthesiology and Pain Medicine, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Korea.
Abstract:
Bispectral index (BIS) values derived from the left and right forehead are usually the same. We report on two patients with unilateral carotid artery stenosis in whom we observed differences between the BIS values obtained from sensors placed on each side of the forehead. During surgery, the BIS values of the diseased side decreased more than those of the opposite side when the mean arterial pressure decreased below 70 mmHg. BIS monitors should be used with caution in patients with unilateral carotid artery and cerebrovascular disease.
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Monitoring Both Arms:
Monitoring BP in both arms during the initial assessment is advisable, as the systolic value may differ by five to ten mm Hg between arms. For subsequent BP assessments, use the arm with the higher reading.
Assessment of blood pressure in brachial artery(two-step method)
Assessment of blood pressure in brachial artery(one-step method)
Prepare for the Procedure:
Sites for measuring blood pressure
The Brachial Artery: Primary Site for Blood Pressure Measurement
