As a critical care pharmacist, your help will be needed to manage hyponatremia, the most common electrolyte disorder. Hyponatremia is linked to increased mortality and even minor hyponatremia is associated with mental status changes and falls.
Emergent. Use 3% NaCl for SEVERE symptoms (coma, seizure, etc), no matter if hyponatremia is acute (within 48 hrs) or chronic. Start with a 100 to 150 mL bolus over 10 to 20 minutes. It seems as safe and effective as a continuous infusion. Or consider 3% NaCl for MODERATE symptoms (vomiting, confusion, etc) in those at risk of developing severe symptoms, such as marathon runners or patients with an intracranial injury. Don’t delay 3% NaCl for central line placement. Data suggest extravasation risk is low with peripheral use for a few days. Aim to raise sodium by 4 to 6 mEq/L in the first 1 to 2 hours. But don’t exceed about 8 mEq/L in 24 hours. Overcorrection can cause osmotic demyelination syndrome, a severe neurological condition.
Non-emergent. Don’t routinely give 3% NaCl for asymptomatic patients or those with MILD symptoms, such as gait changes. Treat these patients based on the underlying cause. For example, use 0.9% NaCl for HYPOvolemic hyponatremia, or diuresis for HYPERvolemic hyponatremia (heart failure, etc). For euvolemic patients with syndrome of inappropriate antidiuretic hormone (SIADH), try fluid restriction. If that’s not enough, consider adding urea oral solution (Ure-Na), an osmotic agent that increases water excretion in the urine. Urea is safe, and limited data suggest it raises sodium at similar amounts as “vaptans” (tolvaptan, etc). But be aware, there’s no good evidence that urea or vaptans improve quality of life or decrease mortality. Get our notes, "Best approach for treating HYPOnatremia" and "Stay alert to drugs that cause hyponatremia".
REFERENCES
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Adrogué HJ, Tucker BM, Madias NE. Diagnosis and Management of Hyponatremia: A Review. JAMA. 2022 Jul 19;328(3):280-291. Available at: https://jamanetwork.com/journals/jama/article-abstract/2794358
Spasovski G, Vanholder R, Allolio B, Annane D, Ball S, Bichet D, Decaux G, Fenske W, Hoorn EJ, Ichai C, Joannidis M, Soupart A, Zietse R, Haller M, van der Veer S, Van Biesen W, Nagler E. Clinical practice guideline on diagnosis and treatment of hyponatraemia. Intensive Care Med. 2014 Mar;40(3):320-31. Available at: https://pubmed.ncbi.nlm.nih.gov/24562549
Decaux G, Gankam Kengne F. Hypertonic saline, isotonic saline, water restriction, long loops diuretics, urea or vaptans to treat hyponatremia. Expert Rev Endocrinol Metab. 2020 May;15(3):195-214. Available at: https://pubmed.ncbi.nlm.nih.gov/32401559
Hoorn EJ, Spasovski G. Recent developments in the management of acute and chronic hyponatremia. Curr Opin Nephrol Hypertens. 2019 Sep;28(5):424-432. Available at: https://journals.lww.com/co-nephrolhypertens/Abstract/2019/09000/Recent_developments_in_the_management_of_acute_and.5.aspx