Cordoba J, Blei A T, Mujais S
Department of Medicine, Lakeside Veterans Administration Medical Center, Chicago, IL 60611, USA.
Artif Organs. 1996 Jul;20(7):800-3. doi: 10.1111/j.1525-1594.1996.tb04544.x.
Ammonia toxicity appears to contribute to the genesis of brain edema, a leading cause of death in fulminant hepatic failure. Because dialysis has been recommended for acute hyperammonemia in other conditions, we have conducted a study to analyze the determinants of ammonia clearance with the use of a single-pass dialyzer. We have used an ionic solution with a constant concentration of ammonia to estimate clearance at different blood flow rates, at dialysate flow rates, and with different dialyzer surfaces. Once hemodialysis had been optimized, we estimated ammonia, glutamine, and urea removal by using a single-compartment model. Our results show that the clearance of ammonia is blood flow dependent and is also influenced by dialysate flow rate and dialyzer surface. At clinically feasible conditions, ammonia can be extracted by more than 80% by setting the dialysate flow at a high rate. In addition to ammonia removal, hemodialysis allows the clearance of urea and glutamine, molecules that can be regarded as ammonia equivalents and that also undergo flow-dependent elimination.
氨中毒似乎是导致脑水肿的原因之一，脑水肿是暴发性肝衰竭的主要死因。由于在其他情况下已推荐对急性高氨血症进行透析，我们开展了一项研究，以分析使用单程透析器时氨清除率的决定因素。我们使用了一种氨浓度恒定的离子溶液，来估计不同血流速率、透析液流速以及不同透析器表面积时的清除率。一旦血液透析得到优化，我们就使用单室模型来估计氨、谷氨酰胺和尿素的清除情况。我们的结果表明，氨的清除率取决于血流，同时也受透析液流速和透析器表面积的影响。在临床可行的条件下，通过将透析液流速设置为高速率，氨的提取率可超过80%。除了清除氨之外，血液透析还能清除尿素和谷氨酰胺，这些分子可被视为氨的等效物，并且其清除也依赖于血流。
