What is the recommended initial insulin dose for the management of diabetic ketoacidosis (DKA)?

Insulin Dosing for Diabetic Ketoacidosis (DKA)

Initial Insulin Therapy

For moderate to severe DKA, the recommended initial insulin dose is a continuous intravenous regular insulin infusion at 0.1 units/kg/hour without an initial bolus dose. 1, 2

• For adult patients with DKA, once hypokalemia (K+ < 3.3 mEq/l) is excluded, begin with continuous IV regular insulin infusion at 0.1 units/kg/hour (approximately 5-7 units/hour in adults) 2
• For pediatric patients, the recommended IV insulin infusion rate is similar at 0.1 units/kg/hour, but an initial insulin bolus is not recommended 2, 1
• This low-dose insulin regimen typically decreases plasma glucose concentration at a rate of 50-75 mg/dl/hour, similar to higher-dose insulin regimens 2

Monitoring and Titration

• If plasma glucose does not fall by 50 mg/dl from the initial value in the first hour, check hydration status; if acceptable, the insulin infusion may be doubled every hour until a steady glucose decline between 50-75 mg/hour is achieved 2
• When serum glucose reaches 250 mg/dl in DKA or 300 mg/dl in HHS, decrease the insulin infusion rate to 0.05-0.1 units/kg/hour (3-6 units/hour) and add dextrose (5-10%) to the IV fluids 2, 1
• Monitor blood glucose every 1-2 hours and draw blood every 2-4 hours to determine serum electrolytes, glucose, BUN, creatinine, osmolality, and venous pH 1, 2

Alternative Approaches for Mild DKA

• For mild DKA, subcutaneous insulin administration can be effective 2, 3
• Patients with mild DKA should first receive a "priming" dose of regular insulin of 0.4-0.6 units/kg body weight, half as an IV bolus and half as a subcutaneous or intramuscular injection 2
• Thereafter, administer 0.1 units/kg/hour of regular insulin subcutaneously or intramuscularly 2
• Recent studies show that subcutaneous rapid-acting insulin analogs every 1-2 hours combined with aggressive fluid management can be as effective as IV insulin in uncomplicated DKA 1, 4

Criteria for Resolution and Transition to Subcutaneous Insulin

• Continue insulin therapy until resolution of ketoacidosis, defined as glucose <200 mg/dl, serum bicarbonate ≥18 mEq/l, venous pH >7.3, and anion gap ≤12 mEq/L 1, 3
• When DKA resolves and the patient can eat, transition to a multiple-dose subcutaneous insulin schedule using a combination of short/rapid-acting and intermediate/long-acting insulin 2, 5
• Administer basal insulin 2-4 hours before stopping the IV insulin infusion to prevent recurrence of ketoacidosis and rebound hyperglycemia 2, 1
• Continue IV insulin infusion for 1-2 hours after the subcutaneous insulin regimen is begun to ensure adequate plasma insulin levels 2, 1

Common Pitfalls to Avoid

• Premature termination of insulin therapy before complete resolution of ketosis can lead to recurrence of DKA 1, 3
• Inadequate monitoring of potassium levels during insulin therapy can cause dangerous hypokalemia 1, 3
• Relying on nitroprusside method to measure ketones is misleading as it only measures acetoacetic acid and acetone, not β-hydroxybutyrate (the strongest and most prevalent acid in DKA) 2
• Abrupt discontinuation of IV insulin without adequate overlap with subcutaneous insulin can lead to poor glycemic control 2, 1
• Interrupting insulin infusion when glucose levels fall below 250 mg/dl instead of adding dextrose to IV fluids can worsen ketoacidosis 3, 6

Special Considerations

• Direct measurement of β-hydroxybutyrate in blood is the preferred method for monitoring DKA resolution 2, 3
• Ketonemia typically takes longer to clear than hyperglycemia, so insulin therapy should continue until ketoacidosis resolves regardless of glucose levels 1, 3
• Low-dose insulin regimens (0.025-0.1 units/kg/hour) have been shown to be effective with minimal risk of hypoglycemia, though the standard dose (0.1 units/kg/hour) may resolve acidosis slightly faster 7, 6
• Bicarbonate administration is generally not recommended for DKA patients with pH >6.9 2, 3