Braz Leandro G, Braz José R Cerqueira, Castiglia Yara M Machado, Vianna Pedro T Galvão, Vane Luiz A, Módolo Norma S Pinheiro, do Nascimento Paulo, da Silva André L, Kinsky Michael P
Department of Anesthesiology, Botucatu Medical School, UNESP, Botucatu - SP, Brazil.
J Invest Surg. 2008 Nov-Dec;21(6):360-8. doi: 10.1080/08941930802440803.
Some properties of the volatile anesthetics, such as vasodilatation and myocardial depression, combined with the sympathetic inhibition that alpha2-agonists can produce, may determine hemodynamic alterations during aortic surgery. The interaction between dexmedetomidine (DEX), an alpha2-agonist, and sevoflurane during aortic surgery is unknown. We studied the effects of DEX on hemodynamics and systemic oxygenation during aortic cross-clamping (Aox) and unclamping (UAox) in sevoflurane-anesthetized dogs. Twenty dogs were anesthetized with sevoflurane and were randomly assigned to two groups prior to Aox and UAox: control, n = 10, received saline infusion only, and DEX (1 microg x kg(-1) load followed by 1 microg x kg(-1) x h(-1) infusion), n = 10. Hemodynamic and oxygenation variables were measured at baseline, after saline or DEX loading dose, 20 and 40 min after Aox, and 20 and 40 min after UAox. After DEX administration, heart rate, cardiac index (CI) and systemic oxygen transport index (DO(2)I) were lower than in control group. Aox increased mean arterial pressure (MAP) and systemic vascular resistance index (SVRI) in both groups, but the effects were greater with DEX. CI, heart rate, and DO(2)I were lower, while central venous pressure (CVP) and pulmonary artery occlusion pressure were higher in DEX compared to control. After UAox, MAP, CVP and SVRI were maintained higher in DEX in relation to control. We conclude that in sevoflurane-anesthetized dogs DEX alters the cardiovascular response during aortic surgery.
一些挥发性麻醉剂的特性，如血管扩张和心肌抑制，再加上α2激动剂可能产生的交感神经抑制作用，可能决定主动脉手术期间的血流动力学改变。在主动脉手术期间，α2激动剂右美托咪定（DEX）与七氟醚之间的相互作用尚不清楚。我们研究了在七氟醚麻醉的犬只进行主动脉阻断（Aox）和解除阻断（UAox）期间，DEX对血流动力学和全身氧合的影响。20只犬用七氟醚麻醉，并在Aox和UAox之前随机分为两组：对照组，n = 10，仅接受生理盐水输注；DEX组（负荷剂量1μg·kg-1，随后以1μg·kg-1·h-1输注），n = 10。在基线、生理盐水或DEX负荷剂量后、Aox后20和40分钟以及UAox后20和40分钟测量血流动力学和氧合变量。给予DEX后，心率、心脏指数（CI）和全身氧输送指数（DO2I）低于对照组。两组中Aox均增加平均动脉压（MAP）和全身血管阻力指数（SVRI），但DEX组的作用更大。与对照组相比，DEX组的CI、心率和DO2I较低，而中心静脉压（CVP）和肺动脉闭塞压较高。UAox后，DEX组的MAP、CVP和SVRI相对于对照组维持在较高水平。我们得出结论，在七氟醚麻醉的犬只中，DEX改变主动脉手术期间的心血管反应。
