Mitch W E, Wilcox C S
Am J Med. 1982 Mar;72(3):536-50. doi: 10.1016/0002-9343(82)90523-x.
A stable volume and composition of extracellular fluid are essential for normal functioning of the body. Since the kidney is primarily responsible for regulating extracellular fluid, loss of kidney function should have catastrophic consequences. Fortunately, even with loss of more than 90 percent of renal function, a remarkable capacity to regulate body fluid volumes and sodium and potassium persists. Nevertheless, this capacity is limited to chronic renal disease and this has important consequences for clinical management of these patients. How can sodium and potassium homeostasis be assessed? Methods for evaluating the steady-state regulation of sodium include measurement of body fluids and their distribution in different compartments and measurement of exchangeable and intracellular sodium. Short-term regulation of body sodium can be assessed from measurement of sodium balance during changes in dietary salt. Potassium is predominantly contained within cells and thus the assessment of its regulation requires special emphasis on measurement of steady-state body stores and potassium distribution across cell membranes. However, the methods used to make all of these measurements require assumptions that may not hold in the altered state of uremia. This raises problems in interpretation requiring critical analysis before conclusions can be made regarding sodium and potassium homeostasis in patients with chronic renal failure. This review focuses on abnormalities of body fluids, sodium and potassium in patients with creatinine clearances of less than 20 ml/min due to chronic renal failure and the impact of conservative therapy, dialysis and renal transplantation on these patients.
细胞外液的稳定容量和成分对于身体的正常功能至关重要。由于肾脏主要负责调节细胞外液，肾功能丧失应会产生灾难性后果。幸运的是，即使肾功能丧失超过90%，调节体液容量以及钠和钾的显著能力仍然存在。然而，这种能力仅限于慢性肾病，这对这些患者的临床管理具有重要影响。如何评估钠和钾的体内平衡？评估钠稳态调节的方法包括测量体液及其在不同腔室中的分布，以及测量可交换钠和细胞内钠。可以通过测量饮食盐分变化期间的钠平衡来评估身体钠的短期调节。钾主要存在于细胞内，因此对其调节的评估需要特别强调测量稳态身体储备以及钾在细胞膜上的分布。然而，用于进行所有这些测量的方法需要一些假设，而这些假设在尿毒症的改变状态下可能不成立。这就产生了解释方面的问题，在对慢性肾衰竭患者的钠和钾体内平衡得出结论之前需要进行批判性分析。本综述重点关注由于慢性肾衰竭导致肌酐清除率低于20 ml/min的患者的体液、钠和钾异常，以及保守治疗、透析和肾移植对这些患者的影响。
