Errors when using IV fluids to treat HYPERnatremia

When correcting hypernatremia, reduce sodium levels no faster than about 10 mEq/L per day due to a concern for cerebral edema....
Mahitab Hany, BS Pharm, PGDipClinPharm, PGDipClinNutrition

Overview

As a critical care pharmacist, take care in monitoring electrolyte disorders in adult ICU patients. Errors commonly occur with IV fluids when treating hypovolemic hypernatremia. Switch to IV fluids over enteral replacement if patients are hemodynamically unstable, NPO, or exhibit severe symptoms (e.g., seizure). Follow these steps...

NPS-adv

Management

Correct hypovolemia first

Correct hypovolemia with normal saline or balanced fluids (e.g., lactated Ringer's), as fluids like D5W leave the intravascular space quickly. If hypernatremia persists after volume resuscitation, switch to D5W. Its dextrose solute makes it close to blood osmolarity, but it acts like "free water" after infusion.

Avoid risks with hypotonic fluids

  • Do NOT allow plain sterile water to be given IV, as it’s extremely hypotonic without solute. This can cause hemolysis, leading to organ failure and death. Limit storage of 1 L sterile water bags to the pharmacy.
  • For non-IV uses like humidifying ventilators, stock 2 L bottles. Note that sterile water isn't the only hypotonic risk; avoid 0.225% NaCl (quarter-normal saline), which may also cause hemolysis.

Use safer fluid options for hypernatremia

Opt for a D5W/0.225% NaCl combo for safe osmolarity. Being premixed, it saves time and prevents compounding errors. If hyperglycemia is a concern with D5W, explain that it only provides 170 kcal/L, which usually isn't problematic. Adjust insulin or reduce dextrose from other sources as needed (e.g., parenteral nutrition).

Reduce sodium gradually to prevent cerebral edema

  • Lower sodium levels cautiously, no faster than about 10 mEq/L per day, to avoid cerebral edema. Use a calculator to determine free water deficit and IV fluid rate.
  • In rare cases of acute, symptomatic hypernatremia (developed within 48 hours), adjust sodium reduction to 1 mEq/L/hr.
  • If hypernatremia is resolving too quickly, reduce the D5W infusion rate, or switch to 0.45% NaCl or D5W/0.225% NaCl, which contain less free water than D5W.

NPS-adv

References

  1. Erstad BL, Huckleberry YC. Extremely hypo-osmolar intravenous solutions to treat hypernatremia: The time has come to stop. Am J Health Syst Pharm. 2021 Dec 24:zxab480.
  2. Dickerson RN, Maish GO 3rd, et al. Safety and efficacy of intravenous hypotonic 0.225% sodium chloride infusion for the treatment of hypernatremia in critically ill patients. Nutr Clin Pract. 2013 Jun;28(3):400-8.
  3. Kraft MD, Btaiche IF, Sacks GS, Kudsk KA. Treatment of electrolyte disorders in adult patients in the intensive care unit. Am J Health Syst Pharm. 2005 Aug 15;62(16):1663-82.