Should I continue 3% hypertonic saline (3% HS) in a patient with correcting hyponatremia, whose sodium level has increased from 106 to 120 mmol/L over 4-5 days?

Stop 3% Hypertonic Saline Immediately

You should STOP 3% hypertonic saline now. Your patient has corrected from 106 to 120 mmol/L over 4-5 days, representing a 14 mmol/L increase—this already exceeds the maximum safe correction limit of 8 mmol/L per 24 hours 1, 2. Continuing hypertonic saline risks severe osmotic demyelination syndrome (ODS), particularly given the magnitude of correction already achieved 1, 3.

Immediate Management Steps

Switch to maintenance fluids immediately:

• Discontinue 3% hypertonic saline 1, 2
• Transition to isotonic (0.9%) normal saline or balanced crystalloid for maintenance 1, 4
• Target maintenance rate: 30 mL/kg/day for adults 1

Monitor aggressively for overcorrection:

• Check serum sodium every 4-6 hours for the next 24-48 hours 1, 2
• Watch for signs of osmotic demyelination syndrome: dysarthria, dysphagia, oculomotor dysfunction, quadriparesis (typically appears 2-7 days after rapid correction) 1, 3

Why This Correction Rate Is Dangerous

Your patient's correction of 14 mmol/L over 4-5 days translates to approximately 2.8-3.5 mmol/L per day, which seems reasonable on the surface. However, the critical issue is the total magnitude of correction 1, 5:

• Maximum safe correction: 8 mmol/L in 24 hours, 12-14 mmol/L in 48 hours 1, 5
• Your patient: 14 mmol/L over 4-5 days (likely exceeded limits in first 48 hours)
• Risk of ODS increases dramatically when correction exceeds 10 mmol/L in 24 hours or 18 mmol/L in 48 hours 3, 5

High-risk populations require even slower correction (4-6 mmol/L per day maximum): patients with advanced liver disease, alcoholism, malnutrition, or prior encephalopathy 1, 2. If your patient has any of these risk factors, the current correction is particularly concerning 1.

Consider Relowering Sodium If Needed

If overcorrection occurred within the last 24-48 hours, consider actively relowering sodium 1, 5:

• Administer D5W (5% dextrose in water) to provide free water 1
• Consider desmopressin (2-4 mcg IV/SC) to terminate unwanted water diuresis and prevent further rise 1, 5
• Goal: bring total 24-hour correction back to ≤8 mmol/L from starting point 1

This intervention is most effective if implemented within 48 hours of overcorrection 5.

Ongoing Management Strategy

Determine the underlying cause of hyponatremia to guide further treatment 1, 4:

• Hypovolemic hyponatremia: Continue isotonic saline for volume repletion, urine sodium <30 mmol/L suggests appropriate response 1, 4
• Euvolemic hyponatremia (SIADH): Implement fluid restriction to 1 L/day, add oral sodium chloride 100 mEq three times daily if needed 1, 2
• Hypervolemic hyponatremia: Fluid restriction to 1-1.5 L/day, discontinue diuretics temporarily if sodium <125 mmol/L 1, 4

Target sodium level of 125-130 mmol/L is adequate for most patients—there is no need to "normalize" sodium to 135-145 mmol/L acutely 1, 3. The goal is symptom resolution and avoiding complications, not achieving perfect biochemical correction 3.

Common Pitfalls to Avoid

• Never continue aggressive correction once symptoms resolve 3, 5
• Never assume "slow and steady" correction over days is safe—the cumulative magnitude matters more than daily rate 1, 5
• Never use 3% hypertonic saline for chronic hyponatremia beyond initial symptom control (first 6 hours) 1, 4
• Inadequate monitoring during correction phase—sodium should be checked every 2-4 hours during active treatment 1, 2

The most critical action now is stopping hypertonic saline and preventing further correction while monitoring closely for ODS 1, 3, 5.