In a patient with hyperchloremic metabolic acidosis, should I administer Dextrose‑Normal Saline (5% dextrose‑0.9% NaCl)?

Should Dextrose-Normal Saline (DNS) Be Given in Hyperchloremic Metabolic Acidosis?

No, DNS (5% dextrose-0.9% NaCl) should not be administered to patients with hyperchloremic metabolic acidosis, as the normal saline component will worsen the hyperchloremia and perpetuate the acidosis.

Understanding Hyperchloremic Metabolic Acidosis

Hyperchloremic metabolic acidosis is a non-anion gap acidosis caused by excessive chloride relative to sodium, which reduces the strong ion difference (SID) and lowers pH 1, 2, 3. This condition commonly develops after aggressive resuscitation with chloride-rich fluids like 0.9% normal saline 1, 4.

• Normal saline contains 154 mEq/L of both sodium and chloride, which is supraphysiologic compared to plasma chloride (98-106 mEq/L) 2, 3.
• Infusion of 0.9% saline inevitably causes hyperchloremia and metabolic acidosis when given at rates of approximately 30 mL/kg/h during surgery or resuscitation 2.
• The acidosis develops because chloride from IV fluids replaces bicarbonate and other anions, decreasing the strong ion difference 3, 4.

Why DNS Worsens Hyperchloremic Acidosis

The dextrose component of DNS does not mitigate the chloride load from the normal saline base. DNS contains the same 154 mEq/L of chloride as standard normal saline, with 5% dextrose added only for caloric support 5.

• Each liter of DNS delivers 154 mEq of chloride, which will further increase serum chloride and worsen the acidosis 2, 4.
• Studies demonstrate that for each mmol/kg of chloride administered, base excess decreases by approximately -0.4 mmol/L 4.
• In pediatric meningococcal sepsis, hyperchloremic acidosis became the dominant cause of metabolic acidosis by 8-12 hours post-resuscitation, directly correlating with the amount of chloride received (r = 0.44) 4.

Appropriate Fluid Choices for Hyperchloremic Acidosis

Use balanced crystalloid solutions or sodium acetate-containing fluids instead of chloride-rich solutions.

Balanced Crystalloids

• Lactated Ringer's solution (sodium 130 mEq/L, chloride 109 mEq/L) does not cause metabolic acidosis when infused at 30 mL/kg/h, unlike normal saline 2.
• PlasmaLyte (sodium 140 mEq/L, chloride 98 mEq/L) maintains physiologic chloride levels 5.
• These solutions have lower chloride content and higher strong ion difference, preventing further acidosis 2, 3.

Sodium Acetate Solutions

• Sodium acetate infusions can be used in place of normal saline to treat hyperchloremic acidosis in critically ill trauma patients 6.
• Acetate is metabolized to bicarbonate, helping correct the acidosis without adding chloride 6.
• Hemodynamic stability is maintained with sodium acetate, contrary to concerns from hemodialysis literature 6.
• Normalization of hyperchloremia and metabolic acidosis occurs faster with sodium acetate compared to continued normal saline administration 6.

Special Consideration: Mitochondrial Disease

In patients with mitochondrial disorders, lactate-free IV fluids such as DNS are recommended perioperatively, but this is a specific exception for preventing lactic acidosis, not for treating hyperchloremic acidosis 5.

• Mitochondrial patients have a tendency to develop lactic acidosis during metabolic stress, which is exacerbated by fasting and surgery 5.
• The recommendation for DNS in this population is to provide dextrose for normoglycemia while avoiding lactate-containing solutions (like Lactated Ringer's) 5.
• This does not apply to general hyperchloremic acidosis management, where the chloride load remains problematic 1, 2, 4.

Monitoring and Resolution

Hyperchloremic acidosis from saline resuscitation is typically self-limited and resolves with adequate urine output and discontinuation of chloride-rich fluids.

• Resolution occurs faster in patients who maintain greater urine output and receive furosemide 4.
• Chloride begins to correct at 24 hours after switching from normal saline to alternative fluids 6.
• The acidosis resolves spontaneously within 24-48 hours after surgery when chloride administration is stopped 3, 4.

Critical Pitfalls to Avoid

• Do not continue DNS or normal saline in established hyperchloremic acidosis, as this perpetuates the problem by adding more chloride 1, 2, 4.
• Do not administer sodium bicarbonate for hyperchloremic acidosis, as the underlying problem is chloride excess, not bicarbonate deficiency; the acidosis resolves with appropriate fluid management 4, 6.
• Do not mistake hyperchloremic acidosis for lactic acidosis or other high anion gap acidoses, as the treatment differs fundamentally—use Stewart's strong ion approach to quantify the causes 1, 4.
• Do not use base deficit alone to guide resuscitation, as persistent base deficit may reflect iatrogenic hyperchloremic acidosis rather than inadequate resuscitation 1, 4.