What are the guidelines for administering maintenance fluids to a patient with Diabetic Ketoacidosis (DKA)?

Maintenance Fluids in Diabetic Ketoacidosis

Initial Fluid Resuscitation Phase (First 1-2 Hours)

Start with isotonic saline (0.9% NaCl) at 15-20 ml/kg/h (approximately 1-1.5 liters in the first hour for average adults) to restore intravascular volume and renal perfusion, regardless of the corrected sodium level. 1, 2

• This aggressive initial rate corrects severe volume depletion and restores renal perfusion 1
• Recent evidence suggests balanced fluids (lactated Ringer's) may achieve faster DKA resolution compared to normal saline, with one study showing 13 vs 17 hours to resolution 3
• However, the American Diabetes Association guidelines still recommend normal saline as standard initial therapy 1, 2

Transition to Maintenance Fluids (After Initial Resuscitation)

After the first 1-2 hours, switch to 0.45% NaCl (half-normal saline) at 4-14 ml/kg/h if the corrected sodium is normal or elevated. 1, 2

• Calculate corrected sodium by adding 1.6 mEq/L for every 100 mg/dL glucose above 100 mg/dL 2
• If corrected sodium is low, continue 0.9% NaCl at the reduced maintenance rate 1
• Studies demonstrate that modest fluid rates (500 ml/h vs 1000 ml/h) achieve equivalent outcomes in patients without extreme volume depletion, with faster bicarbonate recovery at the lower rate 4

Adding Dextrose to Maintenance Fluids

When plasma glucose reaches 250 mg/dL, transition to D5W with 0.45% NaCl (dextrose 5% in half-normal saline) to prevent hypoglycemia while continuing insulin therapy. 2

• This allows continued insulin administration to clear ketones even after glucose normalizes 1, 2
• The dextrose-containing fluid provides free water to correct hypernatremia if present 2

Potassium Supplementation in Maintenance Fluids

Add 20-30 mEq/L potassium to each liter of IV fluid once serum potassium falls below 5.5 mEq/L and adequate urine output is established (≥0.5 ml/kg/hour). 1, 5, 2

• Use a 2/3 KCl and 1/3 KPO4 mixture to address concurrent phosphate depletion 1, 2
• Critical pitfall: If potassium is <3.3 mEq/L, delay insulin therapy until potassium is restored to prevent life-threatening arrhythmias 5, 2
• Total body potassium deficits in DKA typically range from 3-5 mEq/kg body weight despite initially normal or elevated serum levels 1, 5

Fluid Rate Considerations

Target total fluid replacement of estimated deficits within 24 hours, but do not exceed a change in serum osmolality of 3 mOsm/kg/h to prevent cerebral edema. 2

• For patients without severe volume depletion, rates of 500 ml/h are as effective as 1000 ml/h and result in better metabolic recovery 6, 4
• Maximum sodium correction rate should not exceed 8-10 mEq/L per 24 hours 2
• Gradual correction is especially critical in hyperosmolar patients to prevent osmotic demyelination 1

Monitoring During Maintenance Fluid Therapy

Check basic metabolic panel every 2-4 hours during active DKA treatment to adjust fluid composition and electrolyte supplementation. 2, 7

• Monitor glucose hourly and recalculate corrected sodium with each lab draw 2
• Track serum osmolality to ensure safe correction rates 2
• Assess for signs of cerebral edema (headache, altered consciousness, seizures), particularly in children 2
• Once stable, monitoring frequency can decrease to every 4-6 hours 7

Common Pitfalls to Avoid

• Never tie potassium delivery to insulin infusion rates - these require independent titration based on separate monitoring parameters 5
• Avoid excessive fluid administration rates in patients without extreme volume depletion, as modest rates achieve better outcomes 4
• Do not continue isotonic saline throughout treatment if corrected sodium is normal or elevated - switch to hypotonic fluids 1, 2
• Failing to add dextrose when glucose reaches 250 mg/dL forces premature insulin discontinuation and delays ketone clearance 2