Can 5% dextrose in water be used to treat hypernatremia (serum sodium 150 mEq/L) in a patient with congestive heart failure?

D5W Should NOT Be Used for Hypernatremia in CHF Patients

In a CHF patient with hypernatremia (Na 150 mEq/L), D5W is contraindicated because it will worsen volume overload and congestive symptoms; instead, address the underlying cause by adjusting diuretics and ensuring adequate free water intake through enteral routes. 1

Understanding the Clinical Context

Hypernatremia in CHF typically results from excessive diuresis causing volume depletion, not from true sodium excess. 1 This is fundamentally different from hyponatremia in CHF (which is dilutional from volume overload). The key distinction determines your entire management strategy.

Critical First Step: Assess Volume Status

• If hypovolemic (hypotension, orthostatic changes, poor skin turgor): The patient is over-diuresed. Hold or reduce loop diuretics and give isotonic saline (0.9% NaCl) to restore intravascular volume and renal perfusion. 1

• If euvolemic or hypervolemic (persistent congestion): Continue diuretics cautiously at the lowest effective dose while providing free water replacement. 1

Why D5W Is Problematic in CHF

D5W delivers free water intravenously, which:

• Expands intravascular volume acutely, worsening pulmonary congestion and peripheral edema 2
• Provides no sodium, making it ineffective for true volume repletion if the patient is hypovolemic 1
• Can precipitate acute decompensation in patients with marginal cardiac function 2

A 2023 ICU study found D5W lowered sodium by -2.25 mEq/L per liter, but this was in general ICU patients, not CHF patients where volume tolerance is critically limited. 3

Correct Management Strategy

For Hypernatremia WITH Volume Depletion

• Reduce or hold loop diuretics until euvolemia is restored 1
• Administer 0.9% normal saline (not D5W) to restore perfusion 1
• Monitor for BUN elevation disproportionate to creatinine, which signals excessive diuresis 1

For Hypernatremia WITH Persistent Congestion

• Continue loop diuretics at the lowest effective dose to maintain euvolemia 1
• Consider continuous infusion rather than bolus dosing for more controlled diuresis 1
• Provide enteral free water (not parenteral D5W) to correct hypernatremia 1
• Ensure fluid restriction is not excessive—the 2022 ACC/AHA/HFSA guidelines note fluid restriction has uncertain benefit (Class 2b) and overly aggressive restriction reduces quality of life 1

Monitoring Parameters

• Track serum sodium every 4-6 hours during active correction 1
• Maintain potassium 4.0-5.0 mEq/L to prevent arrhythmias 1
• Daily weights and strict intake/output 2
• Watch for mental status changes 1

Medication Adjustments

• Continue ACE-I/ARB and beta-blockers unless hemodynamically unstable 1
• Avoid thiazide diuretics (like metolazone), which markedly increase electrolyte abnormality risk and should only be added for truly refractory edema 1
• Avoid NSAIDs, which cause sodium retention and blunt diuretic efficacy 1

Common Pitfalls to Avoid

• Do not use D5W thinking it's "just free water"—the volume load is poorly tolerated in CHF 1
• Do not restrict fluids excessively—this paradoxically worsens hypernatremia 1, 4
• Do not discharge before achieving euvolemia unless exceptional circumstances exist 1
• Do not add thiazides reflexively—escalate loop diuretic dose first 1

When to Escalate Care

If hypernatremia persists despite optimized management:

• Consider invasive hemodynamic monitoring if volume status cannot be determined clinically 1
• Ultrafiltration may be considered for refractory congestion, but requires careful sodium monitoring as it can worsen hypernatremia 1
• Evaluate for advanced heart failure therapies if refractory 1