What is the starting infusion rate for half normal saline (0.45% sodium chloride solution) in adults, measured in cubic centimeters (cc) per hour?

Half Normal Saline Infusion Rate

The standard rate for half normal saline (0.45% sodium chloride) IV hydration in adults is 75-100 mL/hour (cc/hour) for maintenance fluid therapy. 1

Understanding Half Normal Saline Administration

Half normal saline (0.45% NaCl) is a hypotonic crystalloid solution commonly used for:

• Maintenance fluid therapy
• Treating hypernatremia
• Managing patients with fluid needs who have normal or elevated serum sodium levels

Infusion Rate Guidelines

The appropriate infusion rate depends on several factors:

• For maintenance therapy:

  • 75-100 cc/hour for adults 1

• For active fluid replacement:

  • When corrected serum sodium is normal or elevated: 0.45% NaCl at 4-14 mL/kg/hour 2
  • When corrected serum sodium is low: 0.9% NaCl is preferred instead 2

• For pediatric patients:

  • Once serum glucose normalizes (reaches 250 mg/dL), fluid should be changed to 5% dextrose with 0.45-0.75% NaCl 2

Clinical Considerations for Infusion Rate

When determining the appropriate infusion rate for half normal saline, consider:

1. Patient's hydration status

   • Dehydrated patients may require higher initial rates
   • Euvolemic patients require maintenance rates (75-100 cc/hour)

2. Electrolyte status

   • Monitor serum sodium levels during infusion
   • The induced change in serum osmolality should not exceed 3 mOsm/kg/hour 2

3. Cardiac and renal function

   • Patients with cardiac or renal compromise require more frequent monitoring 1
   • Fluid overload risk is higher in these populations

4. Age considerations

   • Older patients are more susceptible to fluid overload and electrolyte disturbances 1
   • Consider lower infusion rates in elderly patients

Important Precautions

• Avoid rapid infusion of hypotonic solutions as this can lead to cerebral edema
• Monitor electrolytes regularly during administration
• Add potassium (20-30 mEq/L) to the infusion once renal function is confirmed and serum potassium is known 1
• Consider switching to normal saline (0.9% NaCl) if the patient develops hyponatremia

Delivery Considerations

The accuracy of gravity-driven micro-drip infusion sets can vary by up to 2.9-fold depending on:

• Catheter size
• Fluid column height
• Carrier flow 3

For precise administration of half normal saline, especially for patients requiring strict fluid management, consider using an infusion pump rather than gravity-driven administration.