Henrich W L, Hunt J M, Nixon J V
N Engl J Med. 1984 Jan 5;310(1):19-23. doi: 10.1056/NEJM198401053100105.
Routine hemodialysis is associated with an increase in left ventricular contractility that is independent of a change in preload, but the mechanisms responsible are unknown. We investigated the importance of three distinct effects that regularly occur in hemodialysis and could potentially improve left ventricular contractility: the removal of uremic toxins, the increase in the plasma ionized calcium concentration, and the increase in the plasma bicarbonate concentration. Three different dialysates were used for each of eight stable patients on long-term hemodialysis, and left ventricular contractility was assessed by two-dimensional echocardiography before and after each dialysis. In the first procedure neither the ionized calcium nor the bicarbonate concentration was allowed to increase, and left ventricular contractility did not improve. In the second procedure, ionized calcium increased (from 4.4 to 5.4 mg per deciliter, P less than 0.001), bicarbonate concentration was held constant, and contractility increased (from 0.74 to 0.93 circumferences per second, P less than 0.005). In the third procedure, ionized calcium was kept constant, the bicarbonate concentration increased (from 19 to 24 mmol per liter, P less than 0.001), but contractility did not increase. These results suggest that the increase in ionized calcium that occurs in regular dialysis is a key factor in the improvement in left ventricular contractility observed during the procedure.
常规血液透析与左心室收缩力增加有关，这种增加与前负荷的变化无关，但具体机制尚不清楚。我们研究了血液透析中经常出现的、可能改善左心室收缩力的三种不同效应的重要性：清除尿毒症毒素、血浆离子钙浓度升高和血浆碳酸氢盐浓度升高。对8名长期接受血液透析的稳定患者，每种情况都使用三种不同的透析液，每次透析前后通过二维超声心动图评估左心室收缩力。在第一个步骤中，离子钙和碳酸氢盐浓度均未升高，左心室收缩力未改善。在第二个步骤中，离子钙升高（从每分升4.4毫克升至5.4毫克，P<0.001），碳酸氢盐浓度保持不变，收缩力增加（从每秒0.74周长增至0.93周长，P<0.005）。在第三个步骤中，离子钙保持不变，碳酸氢盐浓度升高（从每升19毫摩尔升至24毫摩尔，P<0.001），但收缩力未增加。这些结果表明，常规透析中出现的离子钙升高是该过程中观察到的左心室收缩力改善的关键因素。
