Hamamatsu University School of Medicine, Shizuoka, Japan.
Exp Anim. 2010;59(2):199-205. doi: 10.1538/expanim.59.199.
This study examined the sedative effect of, and hemodynamic response to dexmedetomidine administration in propofol-sedated swine. Sixteen swine were subjects. After anesthetic induction and preparation, the propofol infusion rate was adjusted to maintain a bispectral index (BIS) value between 55 and 65 (i.e., baseline). With the propofol infusion rate fixed at the baseline rate, dexmedetomidine was infused continuously at a rate of 0.2, 0.4, and 0.7 microg.kg(-1).h(-1) for one hour at each rate. The BIS value and hemodynamic parameters were recorded at each step. Dexmedetomidine decreased the BIS value, mean arterial blood pressure, heart rate, cardiac output, and mixed venous oxygen saturation in a dose-dependent manner. The systemic vascular resistance (SVR) did not change, but the pulmonary vascular resistance (PVR) increased. Oxygen delivery (DO(2)) and oxygen consumption (VO(2)) decreased. A small dose of dexmedetomidine (0.2 microg.kg(-1).h(-1)) greatly enhanced the sedative effects of propofol with only small changes in hemodynamics and systemic oxygen balance, suggesting it may be useful in reducing the propofol dose requirement. However, dexmedetomidine 0.4 microg.kg(-1).h (-1) suppressed cardiac contractility, and 0.7 microg.kg(-1).h(-1) induced hemodynamic instability and further systemic oxygen imbalance while the additional sedative effect was limited. A lower dose of dexmedetomidine may be recommended when using it in combination with propofol.
本研究旨在探讨右美托咪定在丙泊酚镇静猪中的镇静效果和血液动力学反应。16 头猪为研究对象。麻醉诱导和准备后，调整丙泊酚输注率以维持脑电双频指数（BIS）值在 55 至 65 之间（即基线）。在丙泊酚输注率固定在基线水平的情况下，连续输注右美托咪定，速度分别为 0.2、0.4 和 0.7μg·kg-1·h-1，每种速度持续 1 小时。在每个步骤中记录 BIS 值和血液动力学参数。右美托咪定以剂量依赖性方式降低 BIS 值、平均动脉血压、心率、心输出量和混合静脉血氧饱和度。全身血管阻力（SVR）不变，但肺血管阻力（PVR）增加。氧输送（DO2）和氧消耗（VO2）减少。小剂量右美托咪定（0.2μg·kg-1·h-1）可显著增强丙泊酚的镇静作用，而对血液动力学和全身氧平衡的影响较小，表明其可能有助于减少丙泊酚的剂量需求。然而，右美托咪定 0.4μg·kg-1·h-1 抑制心肌收缩力，0.7μg·kg-1·h-1 诱导血液动力学不稳定和进一步的全身氧失衡，而额外的镇静作用有限。当与丙泊酚联合使用时，可能推荐使用较低剂量的右美托咪定。
