When to discontinue normal saline (NS) 3 percent in the treatment of severe symptomatic hyponatremia?

When to Discontinue 3% Normal Saline in Severe Symptomatic Hyponatremia

3% normal saline should be discontinued when severe symptoms resolve, at which point the treatment should transition to protocols for mild symptoms or asymptomatic hyponatremia. 1

Decision Algorithm for Discontinuing 3% Saline

Criteria for Discontinuation:

• Resolution of severe symptoms 1
  • Improvement in mental status changes
  • Cessation of seizures
  • Resolution of coma or altered consciousness

Transition After Discontinuation:

1. After severe symptoms resolve:

   • Switch to mild symptom protocol or asymptomatic protocol 1
   • Continue monitoring serum sodium levels (q4hr instead of q2hr) 1
   • Implement fluid restriction to 1L/day 1, 2

2. When to transition to oral sodium supplementation:

   • After discontinuing 3% saline, consider NaCl 100mEq orally TID 2
   • Add high protein diet to augment solute intake 2

Safety Parameters During Correction

• Maximum correction rates:

  • Do not exceed 8 mmol/L in 24 hours 1, 2, 3
  • Initial correction goal: 6 mmol/L over 6 hours or until severe symptoms resolve 1, 2
  • After initial 6 mmol/L correction, limit to only 2 mmol/L in the following 18 hours 1

• Monitoring requirements:

  • During severe symptoms: Check sodium q2hr 1
  • After transition to mild symptom protocol: Check sodium q4hr 1
  • Monitor diuresis closely as it correlates with sodium overcorrection 4

Special Considerations

• Chronic vs. Acute Hyponatremia:

  • Rapid correction (>1 mmol/L/h) should only be used for severely symptomatic and/or acute hyponatremia (≤48 hours) 1, 3
  • For chronic hyponatremia (>48-72 hours), slower correction is safer after initial symptom control 5

• Etiology-specific considerations:

  • For SIADH: After discontinuing 3% saline, implement fluid restriction to 1L/day 2, 3
  • For Cerebral Salt Wasting: Avoid fluid restriction as it can worsen outcomes 2, 3

Potential Complications to Monitor

• Osmotic demyelination syndrome:

  • Risk increases with overly rapid correction of chronic hyponatremia 3, 6
  • Higher risk in patients with severe malnutrition, alcoholism, or liver disease 6
  • If overcorrection occurs, consider relowering serum sodium to stay within safe correction limits 5

• Overcorrection risk factors:

  • Severe symptoms at presentation (38% vs 6% overcorrection risk compared to moderate symptoms) 4
  • Increased diuresis correlates with higher risk of overcorrection 4
  • Consider reducing bolus volume and reevaluating before repeating infusions if diuresis increases 4

Target Sodium Level

• Continue treatment until sodium reaches 131 mmol/L 1
• Exception: Subarachnoid hemorrhage patients receive treatment even for sodium levels of 131-135 mmol/L 1

By following these guidelines, clinicians can safely discontinue 3% normal saline when severe symptoms resolve while avoiding the risks of both undertreating symptomatic hyponatremia and overcorrecting too rapidly.