[The effect of nicardipine on internal carotid artery blood flow velocity, local cerebral blood flow and carbon dioxide reactivity].
To study the effect of nicardipine on the blood flow velocity of the internal carotid artery, on local cerebral blood flow (LCBF), and on carbon dioxide reactivity, an initial dose of 0.5 microgram/kg/min of nicardipine was administered in patients for scheduled craniotomy for cerebral aneurysm clipping under isoflurane anesthesia. This agent was administered until the mean arterial blood pressure decreased and could be maintained at about 75% of the initial value until the completion of aneurysm clipping. The measurements of hemodynamics and LCBF were performed after the exposure of the internal carotid artery (T0), and 10 min, 30 min after the starting of nicardipine (n = 13), (T1, T2 respectively), before aneurysm clipping (T3) and 30 min after its discontinuation (T4). Local cerebral blood flow was measured by the thermal gradient blood flow meter. The blood flow velocity of the internal carotid artery was measured at T0 and T3 by a 20MHz pulsed ultrasound Doppler Flow-meter under surgical microscope. Carbon dioxide reactivity was evaluated with % delta LCBF/delta PaCO2 (%/mmHg) at T0, T3 and T4. Mean arterial blood pressure decreased after nicardipine infusion. Local cerebral blood flow did not change during nicardipine infusion, but blood velocity increased significantly after nicardipine infusion from 43 +/-12 to 55 +/- 12 cm/sec (p = 0.024). Carbon dioxide reactivity did not change after nicardipine infusion but had a close correlation with LCBF before (rs = 0.64, p < 0.05), during (rs = 0.84, p < 0.01) and after hypotension (rs = 0.65, p < 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)
Abe
K
K
Department of Anesthesia, Osaka Police Hospital.
Demizu
A
A
Imanishi
M
M
Iwanaga
H
H
D000328:Adult; D000368:Aged; D001783:Blood Flow Velocity / Q000187:drug effects; D002245:Carbon Dioxide / Q000097:blood*; D002343:Carotid Artery, Internal / Q000187:drug effects* / Q000503:physiopathology; D002560:Cerebrovascular Circulation / Q000187:drug effects*; D005260:Female; D006801:Humans; D006973:Hypertension / Q000188:drug therapy; D002532:Intracranial Aneurysm / Q000097:blood / Q000503:physiopathology / Q000601:surgery; D007431:Intraoperative Complications / Q000188:drug therapy; D008297:Male; D008875:Middle Aged; D009529:Nicardipine / Q000627:therapeutic use*
D002245:Carbon Dioxide; D009529:Nicardipine