Centre for Experimental Anaesthesiology, Emergency and Intensive Care Medicine, Department of Acute Medical Sciences, Catholic University Leuven, Belgium.
Br J Anaesth. 2010 Feb;104(2):143-9. doi: 10.1093/bja/aep354. Epub 2009 Dec 22.
The safety of epidural anaesthesia in patients at risk for right ventricular pressure overload remains controversial. We compared the haemodynamic effects of vascular and cardiac autonomic nerve block, induced by selective lumbar (LEA) and high thoracic epidural anaesthesia (TEA), respectively, in an animal model subjected to controlled acute right ventricular pressure overload.
Eighteen pigs were instrumented with epidural catheters at the thoracic (T) and lumbar (L) level and received separate injections at T2 (1 ml) and L3 (4 ml) with saline (s) or bupivacaine 0.5% (b). Three groups of six animals were studied: (i) a control group (Ls+Ts), (ii) LEA group (Lb+Ts), and (iii) TEA group (Ls+Tb). Haemodynamic measurements including biventricular pressure-volumetry were performed. Right ventricular afterload was then increased by inflating a pulmonary artery (PA) balloon. Measurements were repeated after 30 min of sustained right ventricular afterload increase.
LEA decreased systemic vascular resistance (SVR) and did not affect ventricular function. TEA had minor effects on SVR but decreased left ventricular contractility while baseline right ventricular function was not affected. Control and LEA-treated animals responded similarly to a PA balloon occlusion with an increase in right ventricular contractility and heart rate. Animals pretreated with a TEA did not show this positive inotropic response and developed low cardiac output in the presence of right ventricular pressure overload.
In contrast to LEA, TEA reduced the haemodynamic tolerance to PA balloon occlusion by inhibiting the right ventricular positive inotropic response to acute pressure overload.
在有右心室压力超负荷风险的患者中，硬膜外麻醉的安全性仍存在争议。我们比较了选择性腰椎（LEA）和高胸硬膜外麻醉（TEA）分别诱导的血管和心脏自主神经阻滞对受控急性右心室压力超负荷动物模型的血液动力学影响。
18 头猪在胸（T）和腰（L）水平放置硬膜外导管，并分别在 T2（1ml）和 L3（4ml）给予生理盐水（s）或布比卡因 0.5%（b）注射。六只动物分为三组：（i）对照组（Ls+Ts），（ii）LEA 组（Lb+Ts）和（iii）TEA 组（Ls+Tb）。进行血流动力学测量，包括双心室压力容积测量。然后通过充气肺动脉（PA）球囊增加右心室后负荷。在持续增加右心室后负荷 30 分钟后重复测量。
LEA 降低全身血管阻力（SVR），但不影响心室功能。TEA 对 SVR 影响较小，但降低左心室收缩力，而基线右心室功能不受影响。对照和 LEA 处理的动物对 PA 球囊闭塞的反应相似，右心室收缩力和心率增加。预先用 TEA 处理的动物没有表现出这种正性变力反应，并且在存在右心室压力超负荷时出现低心输出量。
与 LEA 相反，TEA 通过抑制右心室对急性压力超负荷的正性变力反应，降低了对 PA 球囊闭塞的血液动力学耐受性。
