Does using D5NS (5% Dextrose in Normal Saline) worsen acidosis?

D5NS Does Not Worsen Acidosis and May Actually Help Resolve It

D5NS (5% Dextrose in Normal Saline) does not worsen acidosis—the dextrose component can actually accelerate resolution of certain types of acidosis, particularly ketoacidosis, while the normal saline component may delay resolution compared to balanced crystalloids. The key issue is not the dextrose, but rather the high chloride content of the normal saline carrier fluid.

Understanding the Components

The Dextrose Component is Beneficial

• Dextrose administration accelerates ketoacidosis resolution by inducing mitochondrial oxidation of NADH and reducing free fatty acid levels, leading to reversal of acidosis 1
• In alcoholic ketoacidosis, patients receiving modest amounts of IV dextrose (7.0-7.5 gm/hr) showed significantly more rapid improvement in acidotic state compared to saline-only treatment (P < 0.001) 1
• Starvation combined with physiologic stress can cause severe metabolic acidosis, which resolves rapidly with initiation of dextrose-containing IV fluids 2
• Glucose provides the safest, most effective treatment for ketoacidosis, with addition of insulin or bicarbonate usually unnecessary 1

The Normal Saline Component is Problematic

• The American College of Critical Care recommends avoiding normal saline in acidotic patients and instead using balanced crystalloid solutions like Ringer's lactate or Plasma-Lyte to prevent worsening hyperchloremic acidosis 3
• Normal saline should be explicitly avoided in severe acidosis, especially when associated with hyperchloremia, and if used should be limited to a maximum of 1-1.5 L before transitioning to balanced solutions 3
• Balanced crystalloid solutions are preferred because they contain physiological chloride concentrations and avoid exacerbating hyperchloremic acidosis 3

Clinical Evidence in DKA Management

Balanced Solutions Outperform Normal Saline

• Lactated Ringer's was associated with faster time to high anion gap metabolic acidosis resolution compared to normal saline in DKA patients (adjusted hazard ratio 1.325; 95% CI 1.121-1.566; p < 0.001) 4
• Balanced fluids resulted in faster DKA resolution (13 hours vs 17 hours, P = 0.02) compared to normal saline 5
• Balanced solutions were generally associated with faster correction of pH, though time to reach overall DKA endpoints was comparable 6

No Increased Complications with Balanced Solutions

• No difference was found in complications such as nongap metabolic acidosis, hyperchloremia, acute kidney injury, or new renal replacement therapy between lactated Ringer's and normal saline groups 4
• Similar incidence of complications and length of stay was observed between balanced crystalloids and normal saline 4

Practical Algorithm for Fluid Selection in Acidotic Patients

Initial Fluid Choice

1. Start with balanced crystalloids (Ringer's lactate or Plasma-Lyte) for any acidotic patient requiring resuscitation 3
2. If normal saline must be used initially, limit to 1-1.5 L maximum before switching to balanced solutions 3
3. Add dextrose (D5) to the balanced crystalloid when plasma glucose reaches 250 mg/dl in DKA or 300 mg/dl in HHS 7

Special Considerations by Acidosis Type

• For ketoacidosis (diabetic, alcoholic, starvation): Dextrose is therapeutic and accelerates resolution 2, 1
• For lactic acidosis or liver failure: Bicarbonate-buffered solutions are preferred over lactate-buffered solutions 7
• For hyperchloremic acidosis: Immediately switch from any chloride-rich fluid to balanced crystalloids 8

Critical Pitfalls to Avoid

Don't Confuse the Components

• The concern about "worsening acidosis" applies to the normal saline component (high chloride load), not the dextrose 3, 8
• Dextrose itself is beneficial for ketoacidosis resolution and should not be withheld due to acidosis concerns 2, 1

Monitor for Hyperglycemia

• Supra-physiologic glucose concentrations in dialysis or substitution fluids frequently result in excessive glucose intake and hyperglycemia and should be avoided 7
• When adding dextrose, use 5-10% concentration and adjust insulin infusion rate accordingly 7

Ensure Adequate Potassium Replacement

• Dextrose administration, correction of acidosis, and volume expansion all decrease serum potassium concentration 9
• Include 20-30 mEq/L of potassium in IV fluids, using a combination of 2/3 KCl and 1/3 KPO4 7, 8

Bottom Line for Clinical Practice

Use D5 in balanced crystalloids (D5LR or D5 Plasma-Lyte) rather than D5NS for acidotic patients. This approach provides the therapeutic benefit of dextrose for ketoacidosis while avoiding the hyperchloremic acidosis associated with normal saline 3, 4, 5. The dextrose component accelerates acidosis resolution, particularly in ketoacidosis, and should not be withheld due to concerns about worsening acidosis 2, 1.