How should diabetic ketoacidosis be managed and how should the insulin infusion rate be titrated when blood glucose does not adequately decrease?

DKA Management and Insulin Titration When Glucose Fails to Decline Adequately

For moderate-to-severe DKA with inadequate glucose response, maintain the fixed-rate intravenous insulin infusion at 0.1 units/kg/h and add 10% dextrose when glucose falls below 14 mmol/L (250 mg/dL), rather than reducing the insulin rate, to ensure continued ketosis resolution while preventing hypoglycemia. 1

Initial Insulin Dosing Strategy

The 2025 ADA guidelines provide clear algorithmic guidance 1:

For moderate-to-severe DKA:

• Start with 0.1 units/kg/h IV insulin infusion (fixed-rate)
• For mild DKA, consider 0.05 units/kg/h as an alternative starting rate
• Optional bolus: 0.1 units/kg rapid-acting insulin as IV bolus if there's delay in setting up the infusion

For mild-to-moderate DKA (alternative approach):

• Subcutaneous insulin may be used: 0.1 units/kg rapid-acting insulin analog every 1 hour OR 0.2 units/kg every 2 hours

Critical Management When Glucose Doesn't Fall Adequately

First: Verify Adequate Fluid Resuscitation

Before adjusting insulin, ensure fluid replacement is appropriate 1:

• Aim to replace 50% of estimated fluid deficit in the first 8-12 hours
• Use 0.9% NaCl or other crystalloid at clinically appropriate rates
• Some experts recommend withholding insulin until glucose stops dropping with fluid administration alone

Second: Maintain Fixed-Rate Insulin, Add Dextrose

The key principle: Do NOT reduce insulin rate prematurely 1, 2

When blood glucose reaches 14 mmol/L (250 mg/dL):

• Continue the 0.1 units/kg/h insulin infusion unchanged
• Add 10% dextrose infusion alongside the 0.9% NaCl/crystalloid
• Target glucose between 150-200 mg/dL for DKA until resolution
• For HHS, target glucose between 200-250 mg/dL

Why This Approach?

The fixed-rate method prioritizes ketosis resolution over glucose normalization 2. Insulin is needed to suppress ketogenesis and resolve acidosis, which often takes longer than glucose correction. Recent evidence shows that reducing insulin rates too early (even to 0.05 units/kg/h as some UK guidelines suggest) leads to:

• Significant delays in adjusting insulin when needed 3
• No reduction in hypoglycemia rates 3
• Higher rates of early hypoglycemia with fixed-rate protocols 4, 5

Monitoring and Adjustment Algorithm

Check every 2-4 hours until stable 1:

• Electrolytes (especially potassium)
• Renal function
• Venous pH
• Osmolality
• Glucose

If glucose continues to fall despite dextrose:

• Increase dextrose concentration or infusion rate
• Consider adding more carbohydrate-containing fluids
• Do NOT reduce insulin rate until ketosis resolves

If glucose is not falling at all:

• Verify IV access is patent
• Ensure adequate fluid resuscitation (hypovolemia impairs insulin action)
• Check for insulin resistance factors (infection, medications like steroids)
• Consider increasing insulin rate incrementally (e.g., to 0.15 units/kg/h)

Critical Potassium Management

Before starting insulin 1:

• If K+ <3.5 mmol/L: Start insulin but do NOT give potassium; check K+ every 2 hours
• If K+ 3.5-5.0 mmol/L: Give potassium in each liter of IV fluid to maintain K+ between 4-5 mmol/L
• If K+ >5.0 mmol/L: Hold potassium supplementation initially

Hypokalaemia occurs in ~50% of DKA cases during treatment and severe hypokalaemia (<2.5 mEq/L) increases mortality 6.

Resolution Criteria

DKA is resolved when 1:

• Glucose <200 mg/dL (11.1 mmol/L) AND
• Anion gap ≤12 mmol/L AND
• Venous pH >7.3 OR bicarbonate ≥18 mmol/L

Use clinical judgment—do not delay discharge or level of care changes if these exact targets aren't met but patient is clinically improved.

Common Pitfalls to Avoid

1. Reducing insulin rate when glucose normalizes but ketosis persists: This is the most common error. Glucose falls faster than ketones clear 2.

2. Delaying dextrose addition: When glucose reaches 14 mmol/L (250 mg/dL), add dextrose immediately. The 2025 study showed significant delays (median 3.2 hours) in practice 3.

3. Stopping long-acting insulin analogs: If the patient was already taking glargine or detemir, continue these at usual doses 2.

4. Inadequate potassium monitoring: Check every 2 hours initially, as insulin drives potassium intracellularly 6, 1.

5. Using arterial blood gases routinely: Venous blood is adequate unless respiratory compromise exists 2.

Alternative Approach for Mild-Moderate DKA

Recent evidence supports subcutaneous insulin regimens for resource-limited settings 7:

• Glargine 0.2 units/kg + lispro 0.2 units/kg initially
• Then lispro 0.1-0.2 units/kg every 3 hours
• Comparable resolution times with less frequent monitoring
• Can be managed on general medical floors (RN ratio 1:4-5 vs 1:2-3 for IV)

This approach showed 90% resolution within 12 hours with comparable hypoglycemia rates 7.

Special Consideration: Euglycemic DKA

With SGLT-2 inhibitor use, patients may present with DKA and glucose <250 mg/dL 8:

• Start glucose-containing IV fluids immediately
• Use standard insulin dosing
• Expect prolonged duration due to SGLT-2 inhibitor half-life
• The glycosuric effect limits hyperglycemia while ketogenesis continues