What is the recommended protocol for insulin infusion and fluid administration in the management of diabetic ketoacidosis (DKA) in Australia?

Australian Guidelines for DKA Protocol: Insulin Infusion and Fluid Management

For management of diabetic ketoacidosis (DKA) in Australia, initial fluid resuscitation with 0.9% NaCl at 15-20 mL/kg/hour should be administered for 1-2 hours before starting insulin therapy, followed by continuous intravenous insulin at 0.1 U/kg/hour. 1

Diagnostic Criteria

• DKA diagnosis requires:
  • Hyperglycemia (>250 mg/dL or >14 mmol/L)
  • pH <7.3
  • Bicarbonate <15 mEq/L
  • Presence of ketonemia (preferably measured as β-hydroxybutyrate) 1

Fluid Management Protocol

1. Initial Resuscitation Phase:

   • Isotonic saline (0.9% NaCl) at 15-20 mL/kg/hour for the first 1-2 hours 1
   • This addresses severe dehydration and hypotension before insulin administration
   • Improves tissue perfusion and renal function

2. Subsequent Fluid Management:

   • After initial resuscitation, transition to 0.45% saline with 5% glucose when blood glucose falls below 250 mg/dL (14 mmol/L) 1, 2
   • Continue at a rate of approximately 250 mL/hour 2
   • Total fluid replacement typically involves 2-3 L of isotonic saline followed by 2-4 L of glucose-containing hypotonic solution 2

Insulin Therapy Protocol

1. Initiation:

   • Begin insulin therapy 1-2 hours after starting fluid replacement 1
   • Continuous intravenous insulin infusion at 0.1 U/kg/hour 1, 3

2. Titration:

   • Target blood glucose reduction of 50-75 mg/dL (2.8-4.2 mmol/L) per hour 1
   • Continue insulin infusion until DKA resolution (even after blood glucose normalizes) 4
   • Add glucose to IV fluids when blood glucose falls to approximately 250 mg/dL (14 mmol/L) 4

3. Transition to Subcutaneous Insulin:

   • Once DKA resolves (glucose <200 mg/dL, bicarbonate ≥18 mEq/L, pH >7.3), transition to subcutaneous insulin 1
   • Continue IV insulin for 1-2 hours after first subcutaneous dose 1

Electrolyte Management

1. Potassium:

   • Monitor potassium levels every 2-4 hours 1
   • Begin potassium replacement when levels are <5.5 mEq/L and adequate urine output is established 1
   • Typical replacement: 20-30 mEq potassium in each liter of IV fluid

2. Phosphate:

   • Consider replacement if serum phosphate <1.0 mg/dL or in patients with cardiac dysfunction, anemia, or respiratory depression 1

3. Bicarbonate:

   • Not routinely indicated when pH >7.0 1
   • May be considered if pH <6.9 1, 5

Monitoring Protocol

• Blood glucose: Every 1-2 hours until stable 1
• Electrolytes, BUN, creatinine: Every 2-4 hours 1
• Venous pH and anion gap: Every 4-6 hours to evaluate resolution of acidosis 1
• Continuous monitoring of vital signs and neurological status 1

Resolution Criteria

DKA is considered resolved when:

• Blood glucose <200 mg/dL (11 mmol/L)
• Serum bicarbonate ≥18 mEq/L
• Venous pH >7.3
• Normalized anion gap
• Patient is hemodynamically stable 1

Important Caveats

• Cerebral Edema Prevention: Avoid too rapid correction of hyperglycemia; maintain glucose reduction at 50-75 mg/dL/hour 1, 5
• Hypoglycemia Risk: Add glucose to IV fluids when blood glucose falls below 250 mg/dL while continuing insulin to clear ketones 4
• Hypokalemia Risk: Monitor potassium closely and replace as needed; hypokalemia can worsen with insulin therapy 1
• Fluid Overload: Be cautious with fluid administration in patients with cardiac or renal impairment 1

This protocol aligns with current guidelines while acknowledging that most patients can be effectively managed outside of ICU settings with proper monitoring and adherence to protocols 2.