What is the Amboss algorithm for managing diabetic ketoacidosis?

DKA Management Algorithm

For adults with diabetic ketoacidosis, follow a structured protocol prioritizing aggressive fluid resuscitation with isotonic saline at 15-20 ml/kg/h initially, followed by continuous IV regular insulin at 0.1 units/kg/h (without an initial bolus), potassium replacement to maintain levels between 4-5 mEq/L, and frequent monitoring every 2-4 hours until resolution criteria are met (glucose <200 mg/dL, bicarbonate ≥18 mEq/L, pH >7.3). 1

Initial Assessment & Diagnosis

Obtain immediately:

• Venous blood gas (not arterial unless respiratory compromise)
• Complete metabolic panel with calculated anion gap
• Blood glucose
• Serum ketones (β-hydroxybutyrate preferred over nitroprusside method)
• Urinalysis
• ECG

Diagnostic criteria for DKA severity:

• Mild: pH 7.25-7.30, bicarbonate 15-18 mEq/L, glucose >250 mg/dL
• Moderate: pH 7.00-7.24, bicarbonate 10-15 mEq/L
• Severe: pH <7.00, bicarbonate <10 mEq/L 1

Fluid Resuscitation Protocol

Hour 1: Infuse 0.9% NaCl at 15-20 ml/kg/h (approximately 1-1.5 L in average adult) 1

Subsequent hours:

• If corrected sodium is normal or elevated: use 0.45% NaCl at 4-14 ml/kg/h
• If corrected sodium is low: continue 0.9% NaCl at 4-14 ml/kg/h
• Correct sodium for hyperglycemia: add 1.6 mEq for each 100 mg/dL glucose above 100 mg/dL 1

Critical pitfall: In patients with cardiac dysfunction, heart failure, or renal disease, reduce fluid rates significantly to avoid volume overload 2

Insulin Administration

Standard approach (moderate-severe DKA):

• Start continuous IV regular insulin at 0.1 units/kg/h
• Do NOT give initial bolus in most cases 1, 3
• Target glucose decline: 50-75 mg/dL per hour 1

If glucose fails to drop by 50 mg/dL in first hour:

• Verify adequate hydration
• Double insulin infusion rate hourly until achieving steady 50-75 mg/dL/h decline 1

When glucose reaches 250 mg/dL:

• Add 5-10% dextrose to IV fluids
• Continue insulin at 0.1 units/kg/h (do NOT stop insulin)
• Adjust dextrose concentration or insulin rate to maintain glucose 150-200 mg/dL until ketoacidosis resolves 1

Mild DKA alternative:

• Subcutaneous rapid-acting insulin can be used in emergency department
• Give priming dose 0.4-0.6 units/kg (half IV, half SC/IM)
• Then 0.1 units/kg/h SC or IM 4

Potassium Management

Before starting insulin:

• If K+ <3.3 mEq/L: HOLD insulin, give potassium first
• If K+ 3.3-5.5 mEq/L: Add 20-30 mEq/L to IV fluids (2/3 KCl, 1/3 KPO4)
• If K+ >5.5 mEq/L: Hold potassium, recheck in 2 hours 1

Critical point: Insulin drives potassium intracellularly; hypokalemia is a major cause of mortality in DKA management 1

Monitoring Protocol

Every 1-2 hours:

• Capillary blood glucose

Every 2-4 hours:

• Venous pH (adequate for monitoring; arterial unnecessary unless respiratory issues)
• Electrolytes (sodium, potassium, chloride, bicarbonate)
• Anion gap calculation
• Blood urea nitrogen, creatinine 1

Monitoring ketones:

• Use β-hydroxybutyrate blood measurement if available
• Avoid nitroprusside method (urine/serum ketones) - it doesn't measure β-hydroxybutyrate and can falsely suggest worsening ketosis during treatment 1, 4

Bicarbonate Therapy

pH <6.9: Consider 50 mmol sodium bicarbonate in 200 ml sterile water at 200 ml/h 1

pH 6.9-7.0: May give bicarbonate, but evidence is weak 4

pH >7.0: Do NOT give bicarbonate - no benefit demonstrated and may worsen outcomes 1, 5

Phosphate Replacement

Generally NOT recommended - no proven clinical benefit 1

Consider replacement only if:

• Cardiac dysfunction present
• Anemia present
• Respiratory depression
• Serum phosphate <1.0 mg/dL 1

Resolution Criteria

DKA is resolved when ALL three are met:

• Glucose <200 mg/dL
• Serum bicarbonate ≥18 mEq/L
• Venous pH >7.3 1, 4

Transition to Subcutaneous Insulin

Critical timing: Give subcutaneous basal insulin 2-4 hours BEFORE stopping IV insulin to prevent rebound ketoacidosis 5, 3

If patient was on long-acting insulin (glargine/detemir): Continue usual dose throughout DKA treatment 4

For new diagnosis or NPO patients:

• Start basal-bolus regimen: ~0.5-0.8 units/kg/day total
• 50% as long-acting basal insulin
• 50% divided as rapid-acting before meals
• Overlap IV insulin for 1-2 hours after first SC dose 4

Special Populations

Pediatric patients (<20 years):

• NO initial insulin bolus
• Start insulin at 0.1 units/kg/h only when glucose reaches 250 mg/dL
• Fluid rate: 1.5× maintenance (5 ml/kg/h), maximum 2× maintenance
• Cerebral edema risk: Avoid rapid osmotic shifts; gradual correction essential 4, 1

Pregnancy:

• Lower threshold for ICU admission
• More aggressive monitoring
• Earlier insulin initiation 2

Renal failure/dialysis:

• Reduce fluid volumes significantly
• Adjust potassium replacement based on baseline levels
• May require modified insulin dosing 6, 2

SGLT2 inhibitor use:

• High risk for euglycemic DKA (glucose may be <250 mg/dL)
• Discontinue SGLT2 inhibitors 3-4 days before elective surgery
• Maintain high suspicion even with normal glucose 5, 6

Older adults:

• Reduce fluid rates if cardiac/renal comorbidities
• Higher risk for complications
• More conservative correction targets 2

Common Pitfalls

1. Stopping insulin when glucose normalizes - Continue insulin until ketoacidosis resolves, add dextrose instead
2. Abrupt discontinuation of IV insulin - Always overlap with SC insulin by 2-4 hours
3. Using nitroprusside ketone measurements - Falsely suggests worsening; use β-hydroxybutyrate
4. Inadequate potassium replacement - Most common electrolyte-related complication
5. Over-aggressive fluid resuscitation in elderly/cardiac patients - Titrate to clinical status
6. Giving bicarbonate at pH >6.9 - No evidence of benefit, potential harm