Nguyen Minhtri K, Kurtz Ira
Department of Medicine, UCLA Medical Center, Los Angeles, CA, USA.
Nephrol Dial Transplant. 2008 Jul;23(7):2223-7. doi: 10.1093/ndt/gfm932. Epub 2008 Feb 18.
Hypervolemic hypernatremia is caused by an increase in total exchangeable Na(+) and K(+) in excess of an increment in total body H(2)O (TBW). Unlike patients with hypovolemic or euvolemic hypernatremia, treatment needs to be targeted at correcting not only the elevated plasma Na(+) concentration, but also there is an additional requirement to achieve negative H(2)O balance to correct the increment in TBW.
Correction of hypervolemic hypernatremia can be attained by ensuring that the negative Na(+) and K(+) balance exceeds the negative H(2)O balance. These seemingly conflicting therapeutic goals are typically approached by administering intravenous 5% Dextrose (IV D5W) and furosemide.
Currently, there is no quantitative approach to predicting the volume of IV D5W (V(IVF)) that needs to be administered that satisfies these requirements. Therefore, based on the principle of mass balance and the empirical relationship between exchangeable Na(+), K(+), TBW, and the plasma Na(+) concentration, we have derived a new equation which calculates the volume of IV D5W (V(IVF)) needed to lower the plasma Na(+) concentration (Na(+)) to a targeted level (Na(+)) by achieving the desired amount of negative H(2)O balance (V(MB)): V(IVF) = {(Na(+) + 23.8) (TBW(1)) - (Na(+) + 23.8)(TBW(1) + V(MB)) + 1.03 (E x V(input) - E x V(output) - E (V(input) - V(output) - V(MB)))}/1.03 x E where [E] = [Na(+) + K(+)] and input and output refer to non-infusate and non-renal input and output respectively.
This new formula is the first quantitative approach for correcting hypervolemic hypernatremia by achieving negative Na(+) and K(+) balance in excess of negative H(2)O balance.
高血容量性高钠血症是由于可交换钠（Na⁺）和钾（K⁺）总量的增加超过了总体水（TBW）的增加所致。与低血容量性或等容量性高钠血症患者不同，治疗不仅需要针对纠正升高的血浆钠浓度，还需要实现负水平衡以纠正总体水的增加。
通过确保负钠和钾平衡超过负水平衡，可实现高血容量性高钠血症的纠正。这些看似相互矛盾的治疗目标通常通过静脉输注5%葡萄糖（IV D5W）和呋塞米来实现。
目前，尚无定量方法来预测需要输注的IV D5W量（V(IVF)）以满足这些要求。因此，基于质量平衡原理以及可交换钠、钾、总体水和血浆钠浓度之间的经验关系，我们推导了一个新方程，该方程通过实现所需的负水平衡量（V(MB)）来计算将血浆钠浓度（Na⁺）降至目标水平（Na⁺）所需的IV D5W量（V(IVF)）：V(IVF) = {(Na⁺ + 23.8) (TBW(1)) - (Na⁺ + 23.8)(TBW(1) + V(MB)) + 1.03 (E x V(输入) - E x V(输出) - E (V(输入) - V(输出) - V(MB)))}/1.03 x E，其中[E] = [Na⁺ + K⁺]，输入和输出分别指非输注液和非肾脏的输入和输出。
这个新公式是通过实现超过负水平衡的负钠和钾平衡来纠正高血容量性高钠血症的首个定量方法。
