As a critical care pharmacist, you should take care from electrolyte disorders in adult patients in the intensive care unit (ICU). Errors continue to occur when using IV fluids to treat HYPOvolemic HYPERnatremia. Jump to IV fluids instead of enteral replacement if these patients are hemodynamically unstable or NPO, or have severe symptoms (seizure, etc). Follow these steps...
Correct hypovolemia first with normal saline or balanced fluids (lactated Ringer's, etc). Fluids such as D5W aren't a good option for hypovolemia, since they quickly leave the intravascular space. If hypernatremia persists after volume resuscitation, generally switch to D5W. The dextrose solute makes D5W close to the osmolarity of blood, but it acts like "free water" once infused.
Do NOT allow plain sterile water to be given IV. It's extremely hypotonic, since it doesn't contain solute, so giving it IV can cause hemolysis and lead to organ failure and death, and limit storage of 1 L bags to the pharmacy. For use outside of pharmacy, such as humidifying ventilators, try to stock 2 L BOTTLES. But keep in mind, sterile water isn't the only risky hypotonic fluid. Avoid 0.225% NaCl (quarter-normal saline) which can also cause hemolysis.
Use D5W/0.225% NaCl combo instead for a safe osmolarity. Plus it's a premix, so it can save time and prevent compounding errors. If D5W raises hyperglycemia concerns, point out that it only has 170 kcal/L and isn't often a problem. If needed, adjust insulin or decrease dextrose from other sources (parenteral nutrition, etc).
When correcting hypernatremia, reduce sodium levels no faster than about 10 mEq/L per day due to a concern for cerebral edema. Use a calculator to help determine the free water deficit and IV fluid rate. In the rare case of ACUTE, symptomatic hypernatremia that develops in under 48 hours, you can go faster, such as 1 mEq/L/hr. If hypernatremia is resolving too fast, decrease the D5W infusion rate. Or switch to 0.45% NaCl (half-normal saline) or D5W/0.225% NaCl since they have less free water than D5W.
REFERENCES
-
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. Available at: https://academic.oup.com/ajhp/advance-article-abstract/doi/10.1093/ajhp/zxab480/6482579?redirectedFrom=fulltext&login=false
Dickerson RN, Maish GO 3rd, Weinberg JA, Croce MA, Minard G, Brown RO. 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. Available at: https://aspenjournals.onlinelibrary.wiley.com/doi/full/10.1177/0884533613483840
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. Available at: https://academic.oup.com/ajhp/article-abstract/62/16/1663/5135673?redirectedFrom=fulltext&login=false