What is the suggested IV fluid for a patient with suspected diabetic ketoacidosis (DKA)?

Initial IV Fluid for Diabetic Ketoacidosis

Begin with isotonic saline (0.9% NaCl) at 15-20 mL/kg/hour for the first hour of treatment in all adult patients with suspected DKA, regardless of presenting sodium levels. 1, 2

Initial Fluid Resuscitation Protocol

The first hour of DKA management requires aggressive volume expansion to restore intravascular volume and renal perfusion:

• Administer 0.9% normal saline at 15-20 mL/kg body weight/hour (approximately 1-1.5 liters in the average adult patient) 1, 2
• This isotonic fluid choice is appropriate even when measured sodium appears low, as most DKA patients have pseudohyponatremia from hyperglycemia-induced water shifts 3
• The aggressive initial rate addresses the typical 6-9 liter total body water deficit present in DKA 1

Subsequent Fluid Selection (After First Hour)

After the initial resuscitation bolus, fluid choice depends on the corrected serum sodium:

• If corrected sodium is normal or elevated: Switch to 0.45% NaCl (half-normal saline) at 4-14 mL/kg/hour 1
• If corrected sodium is low: Continue 0.9% NaCl at 4-14 mL/kg/hour 1
• Calculate corrected sodium: Add 1.6 mEq/L to measured sodium for every 100 mg/dL glucose above 100 mg/dL 1, 3

Adding Dextrose During Treatment

Once glucose levels decline with insulin therapy:

• Add dextrose 5% to IV fluids when serum glucose falls to 250 mg/dL 2, 4
• Change to 5% dextrose with 0.45-0.75% NaCl while continuing insulin infusion 1, 2
• This prevents hypoglycemia while allowing continued insulin therapy to clear ketones, which take longer to resolve than hyperglycemia 4
• Target glucose maintenance between 150-200 mg/dL until complete DKA resolution 2, 4

Potassium Supplementation in IV Fluids

Once renal function is confirmed and urine output is adequate:

• Add 20-30 mEq/L potassium to IV fluids (use 2/3 KCl and 1/3 KPO₄) 1, 2
• Do not add potassium if serum K⁺ >5.3 mEq/L 2
• Delay insulin therapy if K⁺ <3.3 mEq/L until potassium is repleted, as insulin drives potassium intracellularly and can precipitate life-threatening arrhythmias 2
• Target serum potassium between 4-5 mEq/L throughout treatment 2, 4

Critical Safety Considerations

Avoid overly rapid osmolality correction:

• The induced change in serum osmolality should not exceed 3 mOsm/kg H₂O per hour to prevent osmotic demyelination syndrome 1, 3
• This requires careful monitoring in patients with severe hyperglycemia and hyperosmolarity 1

Monitor for fluid overload:

• In patients with renal or cardiac compromise, frequent assessment of cardiac, renal, and mental status is essential during fluid resuscitation 1
• Hemodynamic monitoring, fluid input/output measurement, and clinical examination guide successful fluid replacement 1

Emerging Evidence on Balanced Crystalloids

While isotonic saline remains the guideline-recommended standard, recent high-quality evidence suggests balanced crystalloids (Ringer's lactate or Plasma-Lyte) may offer advantages:

• Balanced crystalloids resulted in faster DKA resolution (median 13.0 vs 16.9 hours) and shorter insulin infusion duration (median 9.8 vs 13.4 hours) compared to saline in a 2020 cluster randomized trial 5
• Saline can cause hyperchloremic metabolic acidosis, which may delay apparent DKA resolution 5
• However, current American Diabetes Association guidelines still recommend isotonic saline as first-line therapy 1, 2

Monitoring Requirements

Throughout fluid resuscitation:

• Check serum electrolytes, glucose, BUN, creatinine, osmolality, and venous pH every 2-4 hours until stable 2, 4
• Blood glucose should be monitored every 1-2 hours initially 3
• Venous pH is adequate for monitoring acidosis resolution (typically 0.03 units lower than arterial pH) 4

Common Pitfalls to Avoid

• Never treat measured sodium without calculating corrected sodium in DKA—this leads to inappropriate fluid selection 3
• Never stop insulin infusion when glucose normalizes—continue insulin with dextrose-containing fluids until ketoacidosis resolves 2, 4
• Never delay potassium supplementation once renal function is confirmed and K⁺ <5.3 mEq/L—hypokalemia is a major cause of morbidity 2