The Effect of Stellate Ganglion Block on Mean Blood Flow Velocity and Carbon Dioxide Reactivity of the Middle Cerebral Artery. |
Hye Won Lee, Myung Hyun Kim, Byung Kook Chae, Seong Ho Chang |
1Department of Anesthesiology, College of Medicine, Korea University, Seoul, Korea. 2Department of Neurosurgery, College of Medicine, Ewha Womans University, Seoul, Korea. |
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Abstract |
We studied the effect of stellate ganglion block on the mean blood flow velocity and carbon diaxide reactivity of the middle cerehral artery in nine healthy volunteers. Mean blood flow velocity of the right middle cerebral artery was measured under normocapnia and carbon dioxide reactivity to end-tidal PCO2 of 30 mmHg, 40 mmHg, and 50 mmHg was assessed before and after right stellate ganglion block. End-tidal PCO2 was controlled by hyperventilation and rebthing technique. Mean blood flow velocity was measured using transcranial Doppler sonography, and carbon dioxide reactivity was expressed as the percentage change in mean blood flow velocity per unit change in end-tidal PCO2. There was no difference in mean blood flow velocity under normocapnia (37.7+/-1.1 mmHg) between the values measured before stellate ganglion block (60.3+/-4.9 cm/sec) and the values measured after stellate ganglion block (58.6+/-4.9 cm). Mean blood flow velocity increased as end-tidal PCO2 increased from 30 mmHg to 40 mmHg, and from 40 mmHg to 50 mmHg (p<0.01) both before and after stellate ganglion block.
Carbon dioxide reactivity of mean blood flow velocity did not change after stellate ganglion block. Heart rate decreased from 77.1+/-3.5 beats/min to 70+/-2.5 beats/min when end-tidal PCO2 was controlled from 30 mmHg to 40 mmHg after stellate ganglion block (p<0.05). Mean arterial blood pressure did not change after stellate ganglion block at any end-tidal PCO2 level. These results suggest that stellate ganglion block does not induce the change of mean blood flow velocity and carbon dioxide reactivity of the middle cerebral artery. |
Key Words:
Stellate ganglion block; Middle cerebral artery; Mean blood flow velocity; Carbon dioxide reactivity |
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