Trick of the Trade: Sodium Bicarbonate for Acute Symptomatic Hyponatremia

A 25-year-old woman is brought into the emergency department by friends due to “acting weird.” She was at a rave and is reported to have consumed alcohol, marijuana, and ecstasy. On exam, she is afebrile, tachycardic, normotensive, and breathing comfortably on room air. She is lethargic, mumbling incomprehensibly, and does not follow commands. Her glucose is 115 mg/dL, her pregnancy test is negative, her EKG reveals sinus tachycardia, her ethanol level is 30 mg/dL, and a stat CT head is negative. Her chemistry panel reveals a sodium level of 114 mEq/L. You order a 100 mL 3% sodium chloride bolus, but it may take 30 minutes to arrive from the central pharmacy. At this point, the nurse informs you that the patient is seizing.

Trick of the Trade: Crash-formulation sodium bicarbonate for rapid treatment of acute symptomatic hyponatremia

Generally, 100 – 150 mL boluses of 3% sodium chloride are used for the treatment of severe symptomatic hyponatremia. However, it can take some time for these to be prepared by pharmacy. Sodium bicarbonate ampules can be found in crash carts, can be accessed and administered more quickly than 3% sodium chloride, and provide comparable hypertonicity.

Equipment:

• Ampules of sodium bicarbonate 8.4% (often found in crash carts)

Technique:

1.  Slowly administer 1 ampule (50 mL total) of sodium bicarbonate 8.4% over 5 – 10 minutes.

• • An ampule of sodium bicarbonate 8.4% (50 mL) contains 50 mEq of sodium, comparable to 51.3 mEq of sodium found in 100 mL of 3% sodium chloride [1,2].

2. Repeat serum electrolyte testing after administering therapy.

• • If the serum sodium has increased by less than 4 mEq/L, then you can repeat additional hypertonic saline treatment (with another 50 mL sodium bicarbonate ampule or 100 mL of 3% sodium chloride) [3].

• • If serum sodium has increased by 4 mEq/L but the patient remains symptomatic, then hyponatremia is unlikely the cause for the patient’s symptoms and other etiologies should be investigated. A correction of 4 – 6 mEq/L of sodium is sufficient to manage the most severe manifestations of hyponatremia [4].

Caution:

• Be sure to closely follow serum sodium levels. The goal is to raise the sodium only enough to alleviate symptoms and prevent herniation: 4 – 6 mEq/L is usually sufficient.
  • Do not correct the sodium more than 6 mEq/L in 6 hours.
  • Do not correct the sodium more than 8 mEq/L in 24 hours.
  • Rapid overcorrection of sodium risks osmotic demyelination. If overcorrection occurs, consider nephrology or ICU consult.
• Be sure to check with your pharmacists regarding the availability of sodium bicarbonate in your department, as availability may be affected by ongoing national shortages [5].

Discussion:

Sodium bicarbonate: do we still think is it completely useless? What are other ways you have addressed hyponatremia when hypertonic saline was not easily available?

References:

1. Sodium bicarbonate. In: Lexi-Drugs.  Hudson, OH: Lexi-Comp, Inc. [Updated April 08, 2020; Accessed April 17, 2020]. http://online.lexi.com/
2. Sodium chloride. In: Lexi-Drugs.  Hudson, OH: Lexi-Comp, Inc. [Updated April 17, 2020; Accessed April 17, 2020]. http://online.lexi.com/
3. Adrogué HJ, Madias NE. Diagnosis and treatment of hyponatremia. Am J Kidney Dis. 2014;64(5):681-684. PMID: 24996937
4. Sterns RH, Hix JK, Silver S. Treatment of hyponatremia. Curr Opin Nephrol Hypertens. 2010;19(5):493-498. PMID: 20539224
5. “Sodium Bicarbonate Injection.” ASHP, https://www.ashp.org/Drug-Shortages/Current-Shortages/Drug-Shortage-Detail.aspx?id=293&loginreturnUrl=SSOCheckOnly

 

 

 

 

 

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