Why is sodium chloride (NaCl) administered?

Indications for Sodium Chloride Administration

Sodium chloride (NaCl) is primarily administered to treat sodium, chloride, and water deficiencies that commonly occur in many diseases, with specific applications based on the clinical context and patient needs. 1

Primary Indications for Sodium Chloride Administration

• Electrolyte Replacement: Used to correct sodium and chloride deficiencies in conditions where these electrolytes are lost 1
• Fluid Resuscitation: Administered as isotonic solution (0.9% NaCl) for volume expansion in hypovolemic states 2
• Treatment of Hyponatremia: Higher concentrations (3% or 23.4%) are used to treat symptomatic hyponatremia or increased intracranial pressure 2, 3
• Maintenance Fluid Therapy: Used as a component of intravenous maintenance fluid therapy (IV-MFT) in hospitalized patients 2

Clinical Scenarios Requiring Sodium Chloride

Gastrointestinal Disorders

• Intestinal Obstruction: Sodium chloride is indicated when chloride loss is greater than sodium loss (as in pyloric obstruction) or when losses are approximately equal (as in duodenal, jejunal, or ileal obstruction) 1
• Replacement of GI Fluid Losses: Used to replace electrolytes lost through vomiting, nasogastric suction, or diarrhea 1
• Short Bowel Syndrome: Patients with jejunostomy often require sodium chloride supplementation due to high sodium losses in stomal output 2

Cardiovascular and Renal Conditions

• Acute Heart Failure: Recent evidence suggests that sodium chloride infusion (0.9% NaCl) can actually improve diuresis and natriuresis when added to diuretic therapy in acute heart failure 4
• Hypovolemic Hyponatremia: Expansion of plasma volume with normal saline is indicated in hypovolemic hyponatremia, commonly seen with excessive diuretic use in cirrhosis 2
• Dialysis: Sodium chloride is a critical component of dialysate solutions used in hemodialysis to maintain appropriate plasma tonicity 5

Neurological Emergencies

• Cerebral Herniation: Hypertonic sodium chloride (23.4%) can be administered to reduce intracranial pressure and reverse transtentorial herniation 6
• Hyponatremic Encephalopathy: 3% sodium chloride is used to treat symptomatic hyponatremia affecting the central nervous system 2, 3

Pediatric Applications

• Maintenance Fluids: Sodium chloride is a component of maintenance IV fluids in children, with recent guidelines favoring isotonic over hypotonic solutions to prevent iatrogenic hyponatremia 2
• Diabetic Ketoacidosis: Normal saline (0.9% NaCl) is recommended for initial fluid resuscitation in pediatric and adult patients with DKA 2

Administration Considerations

Concentration Selection

• Isotonic (0.9%): For fluid resuscitation and routine maintenance 2
• Hypotonic (0.45%): Used in specific situations but generally not recommended for routine maintenance due to risk of hyponatremia 2
• Hypertonic (3% or 23.4%): For treatment of symptomatic hyponatremia or increased intracranial pressure 2, 6

Safety Considerations

• Peripheral Administration: Even hypertonic solutions like 3% and 23.4% NaCl can be safely administered through peripheral venous access when necessary 3, 6
• Monitoring Requirements: Serum electrolytes should be regularly monitored during sodium chloride administration, especially with hypertonic solutions 2
• Rate of Correction: When treating hyponatremia, correction should not exceed 8-10 mmol/L in 24 hours to prevent central pontine myelinolysis 2

Special Populations

Cirrhosis Patients

• Patients with cirrhosis often develop hyponatremia due to impaired free water excretion 2
• Hypertonic sodium chloride may be used cautiously in symptomatic hyponatremia but can worsen ascites and edema 2

Pediatric Patients

• Isotonic solutions are now preferred over hypotonic solutions for maintenance IV fluids in children to prevent iatrogenic hyponatremia 2
• Initial fluid resuscitation in pediatric DKA should use isotonic saline at 10-20 ml/kg/h 2

Potential Pitfalls and Caveats

• Fluid Overload: Excessive sodium chloride administration can lead to fluid overload, particularly in patients with heart failure, renal failure, or cirrhosis 2
• Hyperchloremic Metabolic Acidosis: Large volumes of 0.9% NaCl can cause hyperchloremic metabolic acidosis 2
• Rapid Correction of Hyponatremia: Correction of serum sodium by more than 9 mmol/L within 24 hours can lead to central pontine myelinolysis 2
• Sodium/Chloride Ratio: The sodium:chloride ratio has prognostic implications in heart failure patients, with elevated ratios associated with increased mortality 7