Can Lactate Ringer's (LR) solution be used to treat hyponatremia?

Lactated Ringer's Solution Should NOT Be Used to Treat Hyponatremia

Lactated Ringer's (LR) solution is contraindicated for treating hyponatremia because it is a hypotonic solution (sodium concentration 130 mEq/L) that will worsen hyponatremia rather than correct it. 1

Why Lactated Ringer's Worsens Hyponatremia

Tonicity and Sodium Content

• LR has a sodium concentration of only 130 mEq/L with an osmolarity of 273 mOsm/L, making it a hypotonic solution 1
• This sodium concentration is below the threshold for hyponatremia (defined as serum sodium <135 mEq/L) 2, 3
• Administering LR to a hyponatremic patient provides free water that dilutes serum sodium further 1

Clinical Evidence Against LR in Hyponatremia

• A secondary analysis from the PROMMTT study demonstrated that Ringer's lactate solutions were associated with higher adjusted mortality compared with normal saline in trauma patients 1
• In pediatric craniofacial surgery, LR was associated with a 50% incidence of hyponatremia (Na <135 mmol/L) during the 2-4 hour period after administration 4
• European trauma guidelines specifically recommend that hypotonic solutions such as Ringer's lactate should be avoided in patients with severe head trauma to minimize fluid shift into damaged cerebral tissue 1

Correct Fluid Choices for Hyponatremia Treatment

Based on Volume Status

For Hypovolemic Hyponatremia:

• Use isotonic (0.9%) saline for volume repletion 2
• Urinary sodium <30 mmol/L has a 71-100% positive predictive value for response to 0.9% saline 2
• Correction rate should not exceed 8 mmol/L in 24 hours 2

For Euvolemic Hyponatremia (SIADH):

• Fluid restriction to 1 L/day is the cornerstone of treatment 2
• For severe symptoms: 3% hypertonic saline with target correction of 6 mmol/L over 6 hours 2
• Add oral sodium chloride 100 mEq three times daily if no response to fluid restriction 2

For Hypervolemic Hyponatremia (cirrhosis, heart failure):

• Fluid restriction to 1-1.5 L/day for sodium <125 mmol/L 2
• Consider albumin infusion in cirrhotic patients 2
• Avoid hypertonic saline unless life-threatening symptoms present 2

Isotonic Solutions That ARE Appropriate

• 0.9% Normal Saline (sodium 154 mEq/L; osmolarity 308 mOsm/L) 1
• PlasmaLyte (sodium 140 mEq/L; osmolarity 294 mOsm/L) 1
• 3% Hypertonic Saline for severe symptomatic hyponatremia 2

Critical Pitfalls to Avoid

• Never use hypotonic fluids (including LR) in hyponatremic patients as this worsens the condition 2, 4
• Do not exceed correction of 8 mmol/L in 24 hours to prevent osmotic demyelination syndrome 2, 3
• In patients with advanced liver disease, alcoholism, or malnutrition, use even more cautious correction rates of 4-6 mmol/L per day 2
• Distinguish between SIADH and cerebral salt wasting in neurosurgical patients, as treatment approaches differ fundamentally 2
• Using fluid restriction in cerebral salt wasting worsens outcomes 2

Special Considerations

High-Risk Populations

• Patients with cirrhosis require correction rates of 4-6 mmol/L per day due to higher risk of osmotic demyelination syndrome 2
• Neurosurgical patients with subarachnoid hemorrhage at risk for vasospasm should not be treated with fluid restriction 2

Monitoring During Correction

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