What is the recommended insulin drip protocol for managing diabetic ketoacidosis (DKA)?

Insulin Drip Protocol for Diabetic Ketoacidosis

For moderate to severe DKA, initiate continuous intravenous regular insulin at 0.1 units/kg/hour after giving an initial IV bolus of 0.1 units/kg, provided serum potassium is ≥3.3 mEq/L. 1, 2

Critical Pre-Insulin Safety Check

Do not start insulin if potassium is <3.3 mEq/L—this is an absolute contraindication that can cause fatal cardiac arrhythmias. 1 If hypokalemia is present:

• Begin isotonic saline at 15-20 ml/kg/hour while holding insulin 1
• Add 20-40 mEq/L potassium to IV fluids once renal function is confirmed 1
• Obtain ECG to assess cardiac effects 1
• Continue aggressive potassium repletion until K+ ≥3.3 mEq/L before starting insulin 1

Initial Insulin Dosing Protocol

For Adults with Moderate-Severe DKA:

• Give IV bolus: 0.1 units/kg regular insulin (some guidelines recommend 0.15 units/kg) 3, 2
• Start continuous infusion: 0.1 units/kg/hour (typically 5-7 units/hour in adults) 3, 1
• Target glucose decline of 50-75 mg/dL per hour 3, 1

For Pediatric Patients:

• Do NOT give an initial insulin bolus 2, 4
• Start directly with continuous infusion at 0.1 units/kg/hour 2

For Mild DKA:

• Subcutaneous or intramuscular regular insulin can be used as an alternative 3
• Give priming dose of 0.4-0.6 units/kg (half IV, half SC/IM), then 0.1 units/kg/hour SC/IM 3

Adjusting the Insulin Infusion

If glucose does not fall by 50 mg/dL in the first hour:

• Verify adequate hydration status 3
• Double the insulin infusion rate every hour until achieving steady decline of 50-75 mg/dL/hour 3

When glucose reaches 250 mg/dL:

• Reduce insulin infusion to 0.05-0.1 units/kg/hour 3, 1
• Add 5-10% dextrose to IV fluids 3
• Continue insulin until DKA resolves, NOT just until glucose normalizes 1, 2

Concurrent Fluid and Electrolyte Management

Fluid Resuscitation:

• Start with isotonic saline 15-20 ml/kg/hour for first hour 1, 2
• Total fluid replacement should be approximately 1.5 times 24-hour maintenance 1

Potassium Replacement:

• Add 20-30 mEq/L potassium to IV fluids once K+ is 3.3-5.5 mEq/L and urine output adequate 1, 2
• Use 2/3 KCl or potassium-acetate and 1/3 KPO4 3
• Target serum potassium 4-5 mEq/L throughout treatment 1, 2

Monitoring Requirements

Check every 2-4 hours: 3, 2

• Blood glucose
• Serum electrolytes (sodium, potassium, chloride)
• Blood urea nitrogen and creatinine
• Venous pH (arterial blood gases generally unnecessary after initial assessment)
• Anion gap
• Serum osmolality

Preferred ketone monitoring: Direct measurement of β-hydroxybutyrate in blood, NOT nitroprusside method which misses the predominant ketone 3, 2

DKA Resolution Criteria

All of the following must be met: 3, 1, 2

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

Important caveat: Ketonemia takes longer to clear than hyperglycemia, so continue insulin until full resolution even if glucose normalizes 3, 2

Transition to Subcutaneous Insulin

This is the most critical step where errors commonly occur:

1. Administer basal insulin (glargine or detemir) 2-4 hours BEFORE stopping IV insulin 1, 2
2. Calculate total daily dose from average IV insulin rate over last 12 hours × 24 5
3. Give 50% as basal insulin once daily, 50% as prandial insulin divided before meals 5
4. Continue IV insulin for 1-2 hours after subcutaneous insulin given 3

Never stop IV insulin without prior basal insulin administration—this is the most common error leading to DKA recurrence. 1

Alternative Approach for Mild-Moderate Uncomplicated DKA

For hemodynamically stable, alert patients with mild-moderate DKA, subcutaneous rapid-acting insulin analogs combined with aggressive fluid management can be as effective and more cost-effective than IV insulin 3. This requires:

• Adequate nurse training 3
• Frequent bedside glucose testing 3
• Appropriate follow-up to avoid recurrence 3

Common Pitfalls to Avoid

• Starting insulin before checking potassium 1
• Using correction-only "sliding scale" insulin without basal coverage after DKA resolves 1, 5
• Stopping IV insulin abruptly without overlap with subcutaneous basal insulin 3, 1
• Using nitroprusside ketone measurements to guide therapy (measures wrong ketones) 3, 2
• Stopping insulin when glucose normalizes but acidosis persists 1, 2