Soliman Rabie Nasr, Hassan Amira Refaie, Rashwan Amr Madih, Omar Ahmed Mohamed
Department of Anaesthesia and Neurosurgical ICU, Faculty of Medicine, Cairo University, Egypt.
Middle East J Anaesthesiol. 2011 Feb;21(1):23-33.
Preliminary data on the perioperative use of dexmedetomidine in patients undergoing craniotomy for brain tumor under general anesthesia indicate that the intraoperative administration of dexmedetomidine is opioid-sparing, results in less need for antihypertensive medication, and may offer greater hemodynamic stability at incision and emergence. Dexmedetomidine, alpha 2 adrenoceptor agonist, is used as adjuvant to anesthetic agents. Relatively recent studies have shown that dexmedetomidine is able to decrease circulating plasma norepinephrine and epinephrine concentration in approximately 50%, decreases brain blood flow by directly acting on post-synaptic alpha 2 receptors, decreases CSF pressure without ischemic suffering and effectively decreases brain metabolism and intracranial pressure and also, able to decrease injury caused by focal ischemia.
This prospective, randomized, double-blind study was designed to assess the perioperative effect of intraoperative infusion of dexmedetomidine in patients with supratentorial tumors undergoing craniotomy under general anesthesia.
Fourty patients with CT- scanning proof of supratentorial tumors were classified equally into 2 groups (twenty patients in each group). Group A:--Dexmedetomidine was given as a bolus dose of 1 microg/kg in 20 minutes before induction of anesthesia, followed by a maintenance infusion of 0.4 microg/kg/hr. The infusion was discontinued when surgery ended. Group B:--The patients received similar volumes of saline.
Heart rate and mean arterial blood pressure, decreased significantly in patients of group A (dexmedetomidine group) compared to group B (placebo group) (p-value < 0.05). There was no significant statistical difference between the two groups regarding the central venous pressure and arterial partial pressure of carbon dioxide (p-value > 0.05). The intraoperative end-tidal sevoflurane (%) in patients of group A was less than in patients of group B (p-value < 0.05). The intracranial pressure decreased in patients of Group A more than group B (p-value < 0.05). The Glasgow coma scale (GCS) improved in patients of group A and deteriorated in patients of Group B with significant statistical difference between the two groups (p-value < 0.05). The total fentanyl requirements from induction to extubation of patients increased in patients of group B more than in patients of group A (p-value < 0.05). The total postoperative patients' requirements for antiemetic drugs within the 2 hours after extubation decreased in patients of group A more than group B (p-value < 0.05). The postoperative duration from the end of surgery to extubation decreased significantly in patients of group A more than group B (p-value < 0.05). The total urine output during the duration from drug administration to extubation of patients increased in patients of group A more than group B (p-value < 0.05).
Continuous intraoperative infusion of dexmedetomidine during craniotomy for supratentorial tumors under general anesthesia maintained the hemodynamic stability, reduced sevoflurane and fentanyl requirements, decreased intracranial pressure, and improved significantly the outcomes.
关于右美托咪定在全身麻醉下接受脑肿瘤开颅手术患者围手术期使用的初步数据表明，术中给予右美托咪定可节省阿片类药物，减少对降压药物的需求，并可能在切口和苏醒时提供更好的血流动力学稳定性。右美托咪定是一种α2肾上腺素能受体激动剂，用作麻醉剂的辅助药物。最近的研究表明，右美托咪定能够使循环血浆去甲肾上腺素和肾上腺素浓度降低约50%，通过直接作用于突触后α2受体减少脑血流量，降低脑脊液压力而无缺血性损害，并有效降低脑代谢和颅内压，还能够减少局灶性缺血造成的损伤。
本前瞻性、随机、双盲研究旨在评估术中输注右美托咪定对全身麻醉下接受幕上肿瘤开颅手术患者的围手术期影响。
40例经CT扫描证实为幕上肿瘤的患者平均分为2组（每组20例）。A组：在麻醉诱导前20分钟给予右美托咪定1μg/kg静脉推注，随后以0.4μg/kg/小时的速度持续输注。手术结束时停止输注。B组：患者接受等量的生理盐水。
与B组（安慰剂组）相比，A组（右美托咪定组）患者的心率和平均动脉血压显著降低（p值<0.05）。两组在中心静脉压和动脉血二氧化碳分压方面无显著统计学差异（p值>0.05）。A组患者术中呼气末七氟醚（%）低于B组患者（p值<0.05）。A组患者的颅内压下降幅度大于B组（p值<0.05）。A组患者的格拉斯哥昏迷量表（GCS）评分改善，B组患者的评分恶化，两组间有显著统计学差异（p值<0.05）。从诱导到拔管，B组患者的芬太尼总需求量增加幅度大于A组患者（p值<0.05）。拔管后2小时内，A组患者术后对抗呕吐药物的总需求量下降幅度大于B组（p值<0.05）。A组患者从手术结束到拔管的术后持续时间显著短于B组（p值<0.05）。从给药到拔管期间，A组患者的总尿量增加幅度大于B组（p值<0.05）。
全身麻醉下幕上肿瘤开颅手术期间持续术中输注右美托咪定可维持血流动力学稳定性，降低七氟醚和芬太尼需求量，降低颅内压，并显著改善预后。
