RESUMO
90 bpm and nicardipine 10?g?kg-1 when MAP increased by 20% of the baseline value. Radial artery was cannulated for continuous BP monitoring and blood sampling. MAP, ECG, HR, SpO2 , PET CO2 and body temperature were continuously monitored during anesthesia. Blood samples were taken before induction of anesthesia (T1), when dura was cut (T2), when aneurysm was clipped (T3 ) and 30 min after clipping (T4 ) for determination of plasma concentrations of AT- Ⅱ , ET and CGRP by radioimmuno-assay.Results Plasma concentration of AT- Ⅱ and HR did not change significantly through out the study. Plasma CGRP concentration and MAP decreased significantly during operation at T2-4 as compared to the baseline values (T1 ) . Plasma ET concentration increased significantly at clipping (T3 ) as compared to that at T2. Conclusion The action of vaso-constrictors (AT- Ⅱ , ET) predominates over that of vaso-dilator during operation. It is important to prevent acute cerebral vasospasm during intracranial aneurysm clipping.