Fall Pamela, Szerlip Harold M
Section of Nephrology, Department of Medicine, Medical College of Georgia, Augusta, Georgia, USA.
Semin Dial. 2010 Nov-Dec;23(6):581-5. doi: 10.1111/j.1525-139X.2010.00790.x. Epub 2010 Dec 20.
Continuous renal replacement therapy (CRRT) has become the modality of choice for critically ill patients. Although often hemodynamically better tolerated than intermittent dialysis, the continuous nature of this therapy may cause significant electrolyte complications. These complications commonly result from removal of electrolytes from the body without adequate replacement or because of the use of trisodium citrate as the anticoagulant. Both hypophosphatemia and hypokalemia frequently complicate prolonged treatment. These complications can be avoided by adding these electrolytes to the dialysate or replacement fluid. The use of citrate, especially if this anticoagulant is not used routinely following established protocols, can also result in several electrolyte abnormalities. Because citrate works by chelating calcium, hypo- and hypercalcemia occur because of under- or overreplacement of calcium. Because citrate is a base equivalent, if the bicarbonate concentration of the dialysate or replacement fluid is not decreased, a metabolic alkalosis may develop. Less commonly, in patients with severe liver dysfunction who cannot metabolize citrate back to bicarbonate, a metabolic acidosis may develop. Although CRRT may cause electrolyte complication it also can be the treatment of choice for the correction of certain electrolyte complications. In patients with acute or chronic renal failure who present with significant dysnatremias, intermittent hemodialysis may cause overly rapid correction of the serum sodium with serious neurologic sequelae. The ability to manipulate the sodium concentration of the dialysate or replacement fluid and the more sustained nature of the treatment allows for a slower correction thus avoiding complications.
连续性肾脏替代治疗（CRRT）已成为重症患者的首选治疗方式。尽管通常在血流动力学方面比间歇性透析耐受性更好，但这种治疗的持续性可能会导致严重的电解质并发症。这些并发症通常是由于在没有充分补充的情况下从体内清除电解质，或者是因为使用枸橼酸钠作为抗凝剂所致。低磷血症和低钾血症在长期治疗中经常并发。通过在透析液或置换液中添加这些电解质可以避免这些并发症。枸橼酸盐的使用，特别是如果不按照既定方案常规使用这种抗凝剂，也可能导致几种电解质异常。由于枸橼酸盐通过螯合钙起作用，低钙血症和高钙血症是由于钙补充不足或过量所致。由于枸橼酸盐是一种碱基等价物，如果透析液或置换液中的碳酸氢盐浓度不降低，可能会发生代谢性碱中毒。在严重肝功能不全、无法将枸橼酸盐代谢回碳酸氢盐的患者中，较少见的情况下可能会发生代谢性酸中毒。尽管CRRT可能会导致电解质并发症，但它也可能是纠正某些电解质并发症的首选治疗方法。在患有急性或慢性肾衰竭且出现明显钠紊乱的患者中，间歇性血液透析可能会导致血清钠过度快速纠正并伴有严重的神经后遗症。能够控制透析液或置换液中的钠浓度以及治疗更持续的性质允许更缓慢的纠正，从而避免并发症。
