Kamel K S, Magner P O, Ethier J H, Halperin M L
Department of Medicine, St. Michael's Hospital, Toronto, Ont., Canada.
Am J Nephrol. 1989;9(4):344-7. doi: 10.1159/000167991.
The purpose of this study was to determine which urine electrolytes should be measured to confirm that the extracellular fluid (ECF) volume is depleted. ECF volume contraction was induced by furosemide administration to rats consuming an electrolyte-free diet. An external potassium balance was achieved by replacing potassium losses with KHCO3 and KCl so that the sodium and chloride deficits were comparable (equivalent to a 30% reduction in ECF volume). As expected, the urine sodium and chloride concentrations fell to 2 +/- 0.3 mmol/l and 3 +/- 0.3 mmol/l, respectively. Rats were then randomized to receive 50-75% of their sodium or chloride deficit as either: NaCl (control group), NH4Cl or NaHCO3 to mimic clinical situations associated with ECF volume contraction. In the NaCl group, the urine sodium and chloride concentrations remained low (6 +/- 2 mmol/l and 7 +/- 2 mmol/l), consistent with persistent ECF volume contraction. Although the NH4Cl group continued to have a low urine sodium concentration (2 +/- 0.2 mmol/l), there was now a marked increase in the urine chloride concentration (51 +/- 7 mmol/l; p less than 0.01 vs. NaCl group). In contrast, although the NaHCO3 group continued to have a low urine chloride concentration (2 +/- 1 mmol/l), there was a significant increase in the urine sodium concentration (19 +/- 3 mmol/l; p less than 0.01 vs. NaCl group). We conclude that the clinical assessment of ECF volume by urine electrolytes requires an evaluation of both the urine sodium and chloride concentrations.
本研究的目的是确定应测量哪些尿液电解质以确认细胞外液（ECF）容量已减少。通过给食用无电解质饮食的大鼠注射呋塞米来诱导ECF容量收缩。通过用KHCO₃和KCl替代钾流失来实现外部钾平衡，以使钠和氯的缺乏量相当（相当于ECF容量减少30%）。正如预期的那样，尿钠和氯浓度分别降至2±0.3 mmol/L和3±0.3 mmol/L。然后将大鼠随机分组，接受其钠或氯缺乏量的50 - 75%，形式如下：NaCl（对照组）、NH₄Cl或NaHCO₃，以模拟与ECF容量收缩相关的临床情况。在NaCl组中，尿钠和氯浓度仍然很低（6±2 mmol/L和7±2 mmol/L），这与持续的ECF容量收缩一致。尽管NH₄Cl组的尿钠浓度持续较低（2±0.2 mmol/L），但尿氯浓度现在显著增加（51±7 mmol/L；与NaCl组相比，p<0.01）。相比之下，尽管NaHCO₃组的尿氯浓度持续较低（2±1 mmol/L），但尿钠浓度显著增加（19±3 mmol/L；与NaCl组相比，p<0.01）。我们得出结论，通过尿液电解质对ECF容量进行临床评估需要同时评估尿钠和氯浓度。
