Duration of Insulin Drip in Diabetic Ketoacidosis (DKA)
An insulin drip should be continued until DKA is fully resolved, which requires all three criteria: glucose <200 mg/dL, serum bicarbonate ≥18 mEq/L, and venous pH >7.3. 1
Resolution Parameters for DKA
DKA is considered resolved when all of the following criteria are met:
These parameters should be monitored by drawing blood every 2-4 hours for determination of serum electrolytes, glucose, blood urea nitrogen, creatinine, osmolality, and venous pH until stable 2, 1
Management During Insulin Drip Therapy
When glucose falls below 200-250 mg/dL, add dextrose to the IV fluids while continuing insulin infusion to clear ketones 1
Target glucose between 150-200 mg/dL until DKA resolution parameters are met 2, 1
Remember that ketonemia typically takes longer to clear than hyperglycemia, necessitating continued insulin therapy even after glucose normalizes 1
Direct measurement of β-hydroxybutyrate in blood is the preferred method for monitoring DKA, as the nitroprusside method only measures acetoacetic acid and acetone 2, 1
Transition from IV to Subcutaneous Insulin
Once DKA is resolved, if the patient is NPO (nothing by mouth), continue intravenous insulin and fluid replacement, and supplement with subcutaneous regular insulin as needed every 4 hours 2
When the patient is able to eat, start a multiple-dose schedule using a combination of short/rapid-acting and intermediate/long-acting insulin 2, 1
Continue intravenous insulin infusion for 1-2 hours after starting subcutaneous insulin to ensure adequate plasma insulin levels 2, 1
An abrupt discontinuation of intravenous insulin coupled with a delayed onset of a subcutaneous regimen can lead to poor glycemic control 2
Common Pitfalls to Avoid
Premature discontinuation of insulin therapy before complete resolution of ketosis can lead to recurrence of DKA 1
Interruption of insulin infusion when glucose levels fall is a common cause of persistent or worsening ketoacidosis 1
Relying solely on glucose levels to determine when to stop insulin therapy, without considering bicarbonate and pH levels 1
Using the nitroprusside method (urine ketones) to monitor treatment response, as it does not measure β-hydroxybutyrate and may misleadingly suggest worsening ketosis during recovery 2, 1
Alternative Approaches
For mild DKA, subcutaneous rapid-acting insulin analogs (such as aspart) given hourly or every 2 hours can be as effective as intravenous insulin 3
Some centers have developed protocols using subcutaneous insulin combinations (rapid-acting plus basal insulin) that may be effective for mild to moderate DKA with less frequent monitoring 4