RESUMO
OBJECTIVE To investigate the effects of different doses of dexmedetomidine on intracranial pressure in patients undergoing gynecological laparoscopic surgery. METHODS Ninety patients undergoing selective gynecological laparoscopic surgery in trendelenburg position were divided into low-dose experimental group （group D 1），high-dose experimental group （group D 2） and control group （group C ）according to random number table ，with 30 cases in each group. Group D 1 and group D 2 received continuous intravenous infusion of dexmedetomidine 1.0 μ g/kg for 10 min for induction of anesthesia ，and then continued intravenous infusion at the rate of 0.4 μg（/ kg·h）and 0.6 μg（/ kg·h）respectively. Group C was continuously pumped with the constant volume of Sodium chloride injection. Three groups stopped pumping 30 minutes before the end of the operation. The heart rate（HR）and mean arterial pressure （MAP）were recorded when entering the room （T0），10 min after intravenous pump of dexmedetomidine（T1），10 min（T2），30 min（T3），60 min（T4）after pneumoperitoneum ，10 min after pneumoperitoneum was closed to restore the supine position （T5）. At the same time ，optic nerve sheath diameter （ONSD）in both eyes was measured by ultrasound，and the occurrence of intraoperative bradycardia and the use of atropine were recorded. RESULTS There was no statistical significance in ONSD ，HR or MAP among 3 groups at T 0（P＞0.05）. Compared with T 0，ONSD of 3 groups were decreased significantly at T 1（except for group C ）；ONSD of 3 groups were increased significantly at T 2-T5，while MAP and HR were all decreased significantly （P＜0.05）. HR of group D 2 was decreased significantly at T 1（P＜0.05）. Compared with group C ， ONSD and HR of group D 1 and D 2 were all decreased significantly at T 1-T5（P＜0.05）. Compared with group C ，the number of patients with bradycardia and those who used atropine in group D 1 and D 2 were increased significantly （P＜0.05）. CONCLUSIONS Continuous pumping of dexmedetomidine during gynecologic laparoscopic surgery can reduce the increase of intracranial pressure in patients ；compared with pumping rate of 0.6 μg（/ kg·h），the change of patient ’s HR tends to be more stable with a pumping rate of 0.4 μg（/ kg·h）.