Can normal saline (0.9% sodium chloride solution) be administered to patients with mild impaired renal function?

Normal Saline in Mild Renal Impairment: Recommendations Based on Evidence

Balanced crystalloids should be used in preference to 0.9% normal saline in patients with mild renal impairment to reduce the risk of adverse kidney events and metabolic complications. 1

Risks of Normal Saline in Renal Impairment

• Normal saline (0.9% sodium chloride) can cause hyperchloremic metabolic acidosis, renal vasoconstriction, and acute kidney injury (AKI), particularly when administered in large volumes 1
• Patients with pre-existing renal impairment are at higher risk for these complications as they have reduced ability to handle the acid-base and electrolyte disturbances caused by high chloride content 1
• The SMART trial (15,802 critically ill patients) demonstrated that patients receiving 0.9% saline had a significantly higher incidence of major adverse kidney events within 30 days compared to those receiving balanced crystalloids (15.4% vs 14.3%) 2
• The SALT trial showed that patients receiving large volumes of 0.9% saline had higher rates of death, need for renal replacement therapy, and persistent renal dysfunction compared to those receiving balanced crystalloids 1

Fluid Distribution Considerations in Renal Impairment

• Research has shown that patients with renal insufficiency have altered fluid distribution patterns when receiving saline infusions 3
• In patients with end-stage renal disease, rapidly infused saline tends to preferentially distribute into the intravascular compartment rather than being appropriately distributed between intravascular and interstitial spaces 3
• This altered distribution can lead to volume overload and associated complications in patients with compromised renal function 1

Clinical Recommendations for Fluid Management

• For patients with mild renal impairment requiring intravenous fluids, balanced crystalloids (such as lactated Ringer's or Plasma-Lyte) should be the first choice 1
• If 0.9% saline must be used, it should be limited to a maximum of 1-1.5 L to minimize the risk of hyperchloremic acidosis and renal injury 1
• Avoid 0.9% saline in patients with:
  • Pre-existing acidosis 1
  • Hyperchloremia 1
  • Need for significant fluid resuscitation 1
  • Risk factors for acute kidney injury 1

Special Considerations

• In kidney transplant recipients, buffered crystalloid solutions are strongly recommended over 0.9% saline due to the risk of delayed graft function 1
• The 2014 KDIGO guidelines for acute kidney injury recommend using isotonic crystalloids rather than colloids for expansion of intravascular volume in patients at risk for AKI or with AKI, but do not specifically recommend against normal saline 1
• More recent evidence and guidelines from 2023-2024 have strengthened the recommendation for balanced crystalloids over normal saline 1

Monitoring Recommendations

• When administering any intravenous fluids to patients with renal impairment:
  • Monitor serum electrolytes, particularly sodium and chloride 1
  • Follow acid-base status through blood gas analysis 1
  • Track urine output and daily fluid balance 1
  • Assess for signs of volume overload 1
  • Monitor renal function through serum creatinine and estimated GFR 1

While normal saline can be administered to patients with mild renal impairment if necessary, the current evidence strongly supports the preferential use of balanced crystalloid solutions to minimize the risk of worsening renal function and metabolic complications.