What is the recommended initial insulin dose for a patient with diabetic ketoacidosis (DKA)?

Insulin Dosing for Diabetic Ketoacidosis

For adult patients with DKA, initiate continuous intravenous regular insulin at 0.1 units/kg/hour without an initial bolus dose. 1

Initial Insulin Administration Protocol

The standard approach is continuous IV regular insulin infusion at 0.1 units/kg/hour, which is the preferred method for moderate to severe DKA. 1, 2 While some older guidelines mention an initial bolus of 0.1 units/kg followed by infusion, the most recent American College of Physicians recommendation eliminates the bolus dose, simplifying the protocol and reducing the risk of rapid glucose decline. 1

Pediatric Dosing Adjustment

• For children, use a lower infusion rate of 0.05-0.10 units/kg/hour 1
• Recent evidence suggests 0.05 units/kg/hour may be as effective as 0.1 units/kg/hour in pediatric patients, with potentially fewer episodes of hypokalemia and hypoglycemia 3

Critical Pre-Insulin Safety Check

Do not start insulin if serum potassium is <3.3 mEq/L—this is an absolute contraindication that can cause life-threatening cardiac arrhythmias. 2

• Begin isotonic saline at 15-20 ml/kg/hour while holding insulin 2
• Add 20-40 mEq/L potassium to IV fluids once renal function is confirmed 2
• Obtain ECG to assess cardiac effects of hypokalemia 2
• Only initiate insulin once K+ ≥3.3 mEq/L 2

Monitoring and Titration

Target Glucose Decline

• Aim for glucose reduction of 50-75 mg/dL per hour 2
• If glucose does not fall by 50 mg/dL in the first hour, verify adequate hydration status 2
• Double the insulin infusion rate hourly until achieving steady decline of 50-75 mg/dL/hour 2

Adding Dextrose

When serum glucose reaches 250 mg/dL, add dextrose 5% to IV fluids (D5W with 0.45-0.75% NaCl) while continuing insulin infusion. 1, 2 This is essential because:

• Ketonemia takes longer to clear than hyperglycemia 4
• Insulin must continue until complete resolution of ketoacidosis, regardless of glucose levels 1
• Target glucose between 150-200 mg/dL until DKA resolves 4

Laboratory Monitoring

• Check blood glucose hourly or more frequently 1
• Draw electrolytes, glucose, BUN, creatinine, osmolality, and venous pH every 2-4 hours 1, 2
• Monitor potassium closely as insulin drives potassium intracellularly 2

DKA Resolution Criteria

All of the following must be met before stopping IV insulin: 2, 4

• Glucose <200 mg/dL
• Serum bicarbonate ≥18 mEq/L
• Venous pH >7.3
• Anion gap ≤12 mEq/L

Transition to Subcutaneous Insulin

Administer basal insulin (glargine or detemir) subcutaneously 2-4 hours BEFORE stopping the IV insulin infusion. 1, 2 This is the most critical step to prevent DKA recurrence.

• Continue IV insulin for 1-2 hours after giving subcutaneous insulin 2, 4
• Failure to overlap insulin administration is the most common error leading to DKA recurrence 2

Alternative Approach for Mild-Moderate Uncomplicated DKA

For hemodynamically stable, alert patients with mild-moderate DKA, subcutaneous rapid-acting insulin analogs (0.25-0.50 units/kg per dose) combined with aggressive fluid management can be as effective as IV insulin and more cost-effective. 1, 2 This requires:

• Patient must be hemodynamically stable and alert 2
• Adequate fluid replacement 2
• Frequent capillary glucose monitoring 2

Common Pitfalls to Avoid

• Never stop IV insulin without prior basal insulin administration—this causes DKA recurrence 2
• Never withhold insulin when glucose normalizes—continue until acidosis resolves 1
• Never start insulin with K+ <3.3 mEq/L—correct hypokalemia first 2
• Never stop adding dextrose once glucose falls below 250 mg/dL—maintain glucose 150-200 mg/dL while clearing ketones 4
• Inadequate potassium monitoring during insulin therapy can cause life-threatening hypokalemia 1, 2