Compare The Effects Of Nitroglycerin And Nicardipine On Cerebral Oxygen Metabolism During Controlled Hypotension In Brain Operation

Background Nitroglycerin and Nicardipine are commonly antihypertensive agents in the clinical use. The former mainly lower the before load of the heart to play the antihypertensive effect.The latter mainly lower the behind load of the heart. The two drugs have short half-life and their dose can be easily adjusted. Blood pressure can recover quickly and there have no rebound after stopped.The technology of controlled hypotension used in brain operation has more reports at home and abroad. But the change of cycle and cerebral oxygen metabolism by applicating the two different antihypertensive drugs has not be found in the published papers,so the objective of the study is to observe the effects of Nitroglycerin and Nicardipine on cycle and cerebral oxygen metabolism during controlled hypotension in brain operations so as to lay basis of safe and effective use of the two drugs in theory and practice and given to contribute to the useage of the clinic.Objective To observe the effects of Nitroglycerin and Nicardipine on cerebral oxygen metabolism during controlled hypotension in brain operations.Methods 24 patients of brain operation were randomized into two groups with 12 cases each. Groupâ… was administered with Nitroglycerin .Groupâ…¡was administered with Nicardipine. Punctured the radial artery at local anesthesia to measured the blood pressure , then the right subclavian vein be punctured and the right internal jugular vein punctured reversing after the induction and intubation. Propofol is continuous infused at the rate of 4-6mg·(kg·h)^-1 by micro-pump to maintain the general anesthesia . Vecuronium and fentanyl are injected discontinuous basis of the need. A bolus of dexamethasone 10 mg was given and 20% mannitol 0. 5g·kg^-1 is infused.Drugs is infusing to controlled the blood plussure by micro-pump at the same time. Groupâ… was given at the rate of 2.5-10μg·(kg·min)^-1, Groupâ…¡was given at the rate of 3-7μg·(kg·min)^-1. Compared with blood pressure before induction, the MAP was reduced by 25 percent and 30 percent and maintained at this level for sixty minutes. The HR ,MAP and CVP are recorded at the moment of the controlled hypotention and 15 minutes,30 minutes, 60 minutes after the controlled hypotention and 30 minute after the controlled hypotention stopped. Blood gas analysis were carried out by taking blood samples from right internal jugular vein bulb and radial artery , and CaO₂ ,CjvO₂,Da-jvO₂ CERO₂were calculated .Result The two groups can reach the target of controlled hypotension. It has no difference in the effects of controlled hypotension (P > 0.05) .HR increased during controlled hypotension .It was higher respectively during 15 minutes to 60 minutes than the moment before controlled hypotension.HR resumed to the original level after the controlled hypotension stopped and there was no difference in the two groups .It has no significantly difference before and after the controlled hypotension in the change of CVP (P>0. 05) .The SjvO₂ increased during controlled hypotension.Compared with those in groupâ… the SjvO₂ increased significantly in groupâ…¡(P<0.05, P<0.01) .The SjvO₂ during controlled hypotension were increased significantly than those before controlled hypotension (P<0. 05) .Da-jvO₂ and CEO₂ decreased during controlled hypotension and it in groupâ…¡decreased significantly than those in groupâ… (P<0.05). It in groupâ…¡decreased significantly at 15 minutes, 30 minutes and 60 minutes during controlled hypotension than the moment before controlled hypotension (P<0. 05) .The CaO₂ and CjvO₂ remained unchanged throughout the process of controlled hypotension(P> 0.05).Conclusion Nicardipine provided an adequate induced hypotension with a lower cerebral oxygenation than Nitroglycerin.