Boezaart A P, van der Merwe J, Coetzee A
Department of Anesthesiology, University of Stellenbosch, Republic of South Africa.
Can J Anaesth. 1995 May;42(5 Pt 1):373-6. doi: 10.1007/BF03015479.
The purpose of this study was to compare surgical conditions for functional endoscopic sinus surgery (FESS) under general anaesthesia during controlled induced hypotension, using either sodium nitroprusside (SNP) or esmolol. Twenty patients, assigned to receive either of the drugs as the primary hypotensive agent, were studied. The same surgeon, blinded to the hypotensive agent used and the haemodynamic variables, performed all the operations. The surgeon used a category scale (0-5) to assess surgical conditions--a value of 2-3 being ideal. Patients were positioned in 5 degrees reverse Trendelenburg position and the mean arterial blood pressure (MABP) was reduced in steps of 5 mmHg. The anaesthetist prompted category scale estimations by the surgeon following a change in any of the haemodynamic variables. Average category scale (ACS) values were compared between the two groups for four data groups, i.e., MABP > 65 mmHg (mild), 60-64 mmHg, 55-59 mmHg and 50-54 mmHg. Pre-treatment MABP was 79.8 +/- 10.4 mmHg in the SNP group and 76.1 +/- 6.8 mmHg in the esmolol group. At mild SNP-induced hypotension, surgical conditions were poor (ACS = 3.63 +/- 0.22; mean +/- SEM), while in the esmolol group, ideal surgical conditions (ACS = 2.94 +/- 0.34) were recorded at MABP > 65 mmHg. The combined effects of increased venous drainage due to the reverse Trendelenburg position, hypotension as well as capillary vasoconstriction due to unopposed alpha-adrenergic effect on the mucous membrane vasculature in the esmolol group (as opposed to vasodilatation in the SNP group) probably caused the superior surgical conditions.
本研究的目的是比较在全身麻醉下进行功能性鼻内镜鼻窦手术（FESS）时，使用硝普钠（SNP）或艾司洛尔进行控制性诱导低血压时的手术条件。研究了20例患者，他们被分配接受其中一种药物作为主要降压药物。由同一位对所用降压药物和血流动力学变量不知情的外科医生进行所有手术。外科医生使用分类量表（0 - 5）评估手术条件，2 - 3分为理想值。患者取头高脚低位5度，平均动脉血压（MABP）以5 mmHg的步长降低。麻醉医生在任何血流动力学变量发生变化后提示外科医生进行分类量表评估。比较了两组在四个数据组（即MABP > 65 mmHg（轻度）、60 - 64 mmHg、55 - 59 mmHg和50 - 54 mmHg）下的平均分类量表（ACS）值。SNP组治疗前MABP为79.8±10.4 mmHg，艾司洛尔组为76.1±6.8 mmHg。在轻度SNP诱导的低血压状态下，手术条件较差（ACS = 3.63±0.22；平均值±标准误），而在艾司洛尔组，当MABP > 65 mmHg时记录到理想的手术条件（ACS = 2.94±0.34）。艾司洛尔组由于头高脚低位导致静脉引流增加、低血压以及对粘膜血管系统无对抗的α - 肾上腺素能效应引起的毛细血管收缩（与SNP组的血管扩张相反）的综合作用可能导致了更好的手术条件。
