Jalonen J, Hynynen M, Kuitunen A, Heikkilä H, Perttilä J, Salmenperä M, Valtonen M, Aantaa R, Kallio A
Department of Anesthesiology, Turku University Hospital, Finland.
Anesthesiology. 1997 Feb;86(2):331-45. doi: 10.1097/00000542-199702000-00009.
Alpha 2-adrenergic agonists decrease sympathetic tone with ensuing attenuation of neuroendocrine and hemodynamic responses to anesthesia and surgery. The effects of dexmedetomidine, a highly specific alpha 2-adrenergic agonist, on these responses have not been reported in patients undergoing coronary artery bypass grafting.
Eighty patients scheduled for elective coronary artery bypass grafting received, in a double-blind manner, either a saline placebo or a dexmedetomidine infusion, initially 50 ng.kg-1.min-1 for 30 min before induction of anesthesia with fentanyl, and then 7 ng.kg-1.min-1 unit the end of surgery. Filling pressures, blood pressure, and heart rate were controlled by intravenous fluid and by supplemental anesthetics and vasoactive drugs.
Compared with placebo, dexmedetomidine decreased plasma norepinephrine concentrations by 90%, attenuated the increase of blood pressure during anesthesia (3 vs. 24 mmHg) and surgery (2 vs. 14 mmHg), but increased slightly the need for intravenous fluid challenge (29 vs. 20 patients) and induced more hypotension during cardiopulmonary bypass (9 vs. 0 patients). Dexmedetomidine decreased the incidence of intraoperative (2 vs. 13 patients) and postoperative (5 vs. 16 patients) tachycardia. Dexmedetomidine also decreased the need for additional doses of fentanyl (3.1 vs. 5.4), the increments of enflurane (4.4 vs. 5.6), the need for beta blockers (3 vs. 11 patients), and the incidence of fentanyl-induced muscle rigidity (15 vs. 33 patients) and postoperative shivering (13 vs. 23 patients).
Intraoperative intravenous infusion of dexmedetomidine to patients undergoing coronary artery revascularization decreased intraoperative sympathetic tone and attenuated hyperdynamic responses to anesthesia and surgery but increased the propensity toward hypotension.
α2肾上腺素能激动剂可降低交感神经张力，从而减弱对麻醉和手术的神经内分泌及血流动力学反应。对于接受冠状动脉搭桥术的患者，高特异性α2肾上腺素能激动剂右美托咪定对这些反应的影响尚未见报道。
80例择期行冠状动脉搭桥术的患者，以双盲方式接受生理盐水安慰剂或右美托咪定输注，麻醉诱导前30分钟先给予50 ng·kg-1·min-1，然后以7 ng·kg-1·min-1持续至手术结束。通过静脉输液、补充麻醉剂和血管活性药物来控制充盈压、血压和心率。
与安慰剂相比，右美托咪定使血浆去甲肾上腺素浓度降低90%，减弱了麻醉期间（3 mmHg对24 mmHg）和手术期间（2 mmHg对14 mmHg）血压的升高，但静脉补液需求略有增加（29例对20例），并在体外循环期间导致更多低血压（9例对0例）。右美托咪定降低了术中（2例对13例）和术后（5例对16例）心动过速的发生率。右美托咪定还减少了芬太尼额外剂量的需求（3.1对5.4）、恩氟烷的增加量（4.4对5.6）、β受体阻滞剂的需求（3例对11例），以及芬太尼诱导的肌肉强直（15例对33例）和术后寒战（13例对23例）的发生率。
在接受冠状动脉血运重建术的患者中术中静脉输注右美托咪定可降低术中交感神经张力，减弱对麻醉和手术的高动力反应，但增加了低血压倾向。
