How can dextrose be used to slow sodium correction in patients with severe hyponatremia?

Using Dextrose to Slow Sodium Correction in Severe Hyponatremia

If overcorrection of hyponatremia occurs (>8 mmol/L in 24 hours), immediately discontinue current fluids and switch to D5W (5% dextrose in water) to relower sodium levels, combined with desmopressin administration to prevent osmotic demyelination syndrome. 1

When Overcorrection Occurs

Immediate intervention is critical when sodium correction exceeds safe limits:

• Stop all hypertonic or isotonic saline infusions immediately 1
• Switch to D5W (5% dextrose in water) infusion to provide free water without sodium 1, 2
• Administer desmopressin to slow or reverse the rapid rise in serum sodium 1, 3
• The goal is to bring the total 24-hour correction back to no more than 8 mmol/L from the starting point 1

Target Correction Rates to Prevent Overcorrection

Maximum safe correction rates vary by risk profile:

• Standard risk patients: 4-8 mmol/L per day, not exceeding 10-12 mmol/L in 24 hours 1
• High-risk patients (advanced liver disease, alcoholism, malnutrition, severe hyponatremia): 4-6 mmol/L per day, not exceeding 8 mmol/L in 24 hours 1, 4
• Avoid short-term spikes exceeding 0.5 mmol/L per hour, even if overall 24-hour rate appears acceptable 4

Special Scenario: CRRT Patients

For patients on continuous renal replacement therapy (CRRT) at risk of overcorrection:

• Calculate and infuse D5W prefilter (before the blood pump) to dilute the effective sodium concentration of replacement fluids 5
• This allows delivery of recommended effluent volumes (20-25 mL/kg/hr) while preventing excessive sodium correction 5
• Use a simplified equation to determine D5W rate based on prescribed effluent volume 5
• Monitor sodium levels closely; if overcorrection occurs, increase D5W rate to bring sodium back down 5

Clinical Evidence for Relowering Strategy

The relowering approach has demonstrated favorable outcomes even with delayed intervention:

• In documented cases of ODS following overcorrection (sodium rise of 121 mmol/L in 8 hours from 101 mmol/L), combined D5W and desmopressin therapy resulted in significant improvement in conscious level and motor function 3
• Regardless of timing of neurologic sequelae, attempting sodium relowering with D5W and desmopressin while monitoring biochemical and neurologic markers is worthwhile 3
• Historical data shows that neurologic complications occur when correction exceeds 12 mmol/L per day, while slower correction results in uneventful recoveries 6

Critical Monitoring During Correction

Intensive monitoring is essential to detect and prevent overcorrection:

• Check sodium levels every 2 hours during initial correction for severe symptoms 1
• Check every 4 hours after resolution of severe symptoms 1
• Watch for signs of osmotic demyelination syndrome (dysarthria, dysphagia, oculomotor dysfunction, quadriparesis) typically occurring 2-7 days after rapid correction 1

Common Pitfall to Avoid

The most dangerous error is assuming isotonic saline is "safe" for all hyponatremia:

• Isotonic saline can cause rapid overcorrection in certain conditions, particularly when combined with simultaneous correction of hypokalemia 2
• In one documented case, isotonic saline led to a 17 mmol/L rise in the first 24 hours, resulting in extra-pontine ODS despite switching to D5W 2
• Hypokalemia and its active correction can facilitate ODS onset, requiring even more cautious sodium correction 2