[A comparison of induced hypotensive anesthesia using trimetaphan, prostaglandin E1 and nicardipine for neurosurgery]

We performed hypotensive anesthesia using trimetaphan, prostaglandin E1, or nicardipine for eighteen patients undergoing cerebral aneurysm clipping. We measured the hemodynamic parameters (systolic arterial pressure, diastolic arterial pressure, and heart rates), concentration of catecholamines in blood (epinephrine, norepinephrine), blood platelet counts, and aggregation of blood platelets, before induction of anesthesia, before induced hypotension, during hypotension, after hypotension, and at the end of operation. Hypotension was produced rapidly, and hemodynamics was stable with any of the three drugs. In trimetaphan group, however, recovery time of arterial pressure was longer than in other two groups. There was no significant change of catecholamine during induced hypotension in prostaglandin E1 and nicardipine groups. However, in trimetaphan group, concentration of norepinephrine in blood decreased significantly during hypotension. No significant change was observed in either platelet count or platelet aggregation. These results suggest that trimetaphan has an effect to suppress excretion of stress hormones, and prostaglandin E1 and nicardipine have no influence on blood catecholamine levels and aggregation of platelet. We consider that nicardipine is useful as a hypotensive drug for neurosurgery.