Honarmand A, Safavi M R
Department of Anesthesiology and Intensive Care, Isfahan University School of Medicine, Isfahan, Iran.
Eur J Anaesthesiol. 2007 Jun;24(6):511-5. doi: 10.1017/S0265021506002055. Epub 2007 Jan 4.
Preoperative oral dextromethorphan and intravenous clonidine attenuate arterial pressure and heart rate increases during tourniquet inflation under general anaesthesia. The effect of preoperative oral clonidine on these variables has not been investigated.
We designed this study to compare the effect of preoperative oral dextromethorphan or clonidine on haemodynamic changes during tourniquet inflation in 75 patients undergoing lower limb surgery under general anaesthesia. Patients were randomly assigned into three groups: dextromethorphan 30 mg (n = 25), clonidine 3 microg kg(-1) (n = 25) and placebo (n = 25). Anaesthesia was maintained with isoflurane 1.2% and N2O 50% in oxygen with endotracheal intubation. Dextromethorphan, clonidine or placebo was given orally in a double-blinded fashion 90 min before induction of anaesthesia. Systolic, diastolic and mean arterial pressure and heart rate were measured at 0, 30, 45, 60 min after the start of tourniquet inflation, before tourniquet release and 20 min after tourniquet deflation.
Systolic, diastolic and mean arterial pressure were significantly lower in the clonidine group compared with control after 45, 60 min tourniquet inflation and before tourniquet release (P < 0.05). Twenty minutes after deflation, diastolic and mean arterial pressure in the control group were still increased and significantly higher compared with the clonidine group (P < 0.05). Development of more than a 30% increase in systolic arterial pressure during tourniquet inflation was more frequent in the control group than in the other groups.
Preoperative oral clonidine 3 microg kg(-1) significantly prevented tourniquet-induced systemic arterial pressure increase in patients under general anaesthesia better than oral dextromethorphan.
术前口服右美沙芬和静脉注射可乐定可减轻全身麻醉下止血带充气期间动脉压和心率的升高。术前口服可乐定对这些变量的影响尚未得到研究。
我们设计本研究以比较术前口服右美沙芬或可乐定对75例接受全身麻醉下下肢手术患者止血带充气期间血流动力学变化的影响。患者被随机分为三组：右美沙芬30毫克（n = 25）、可乐定3微克/千克（n = 25）和安慰剂（n = 25）。采用1.2%异氟烷和50%氧化亚氮混合氧气进行气管插管维持麻醉。在麻醉诱导前90分钟以双盲方式口服右美沙芬、可乐定或安慰剂。在止血带充气开始后0、30、45、60分钟、止血带松开前以及止血带放气后20分钟测量收缩压、舒张压、平均动脉压和心率。
在止血带充气45、60分钟后以及止血带松开前，可乐定组的收缩压、舒张压和平均动脉压显著低于对照组（P < 0.05）。放气20分钟后，对照组的舒张压和平均动脉压仍升高，且显著高于可乐定组（P < 0.05）。止血带充气期间收缩压升高超过30%的情况在对照组比其他组更常见。
术前口服3微克/千克可乐定比口服右美沙芬能更有效地预防全身麻醉患者止血带引起的全身动脉压升高。
