What is the recommended infusion rate for a patient with diabetic ketoacidosis (DKA), particularly once their serum glucose level reaches hyperglycemia?

Infusion Rate for DKA When Glucose Reaches Hyperglycemic Levels

When serum glucose reaches 250 mg/dL during DKA treatment, switch to 5% dextrose in 0.45% saline (D5 1/2 NS) with 20-30 mEq/L potassium at 150-250 mL/hour (approximately 4-14 mL/kg/hour), while continuing insulin infusion at 0.1 units/kg/hour until ketoacidosis resolves. 1

Fluid Composition Change at Glucose 250 mg/dL

• Switch from 0.45% or 0.9% saline to D5 1/2 NS when glucose drops to 250 mg/dL 1
• The dextrose prevents hypoglycemia while insulin continues to clear ketones 1
• Add 20-30 mEq/L potassium (2/3 KCl and 1/3 KPO4) to the dextrose-containing fluid once renal function is confirmed 1

Infusion Rate After Glucose Reaches 250 mg/dL

• Maintain fluid rate at 4-14 mL/kg/hour (approximately 150-250 mL/hour for average adults) 1
• This translates to roughly 250 mL/hour based on historical protocols that used 2-4 liters over 8-16 hours 2
• The rate depends on corrected serum sodium: use 0.45% saline if corrected sodium is normal/elevated, or 0.9% saline if corrected sodium is low 1

Critical Insulin Management

• Do NOT stop insulin when glucose reaches 250 mg/dL - this is a common and dangerous error 1, 3
• Continue insulin infusion at 0.1 units/kg/hour until DKA resolves (pH >7.3, bicarbonate ≥18 mEq/L) 1
• In severe DKA, insulin may need to continue at 4-6 units/hour or higher with appropriate glucose infusion to prevent hypoglycemia 3
• The goal is to maintain glucose 150-200 mg/dL while continuing insulin therapy until ketoacidosis clears 1

Monitoring Parameters

• Check glucose and electrolytes every 2-4 hours during active treatment 4, 1
• Monitor venous pH and anion gap (arterial blood gases are generally unnecessary) 4, 1
• Ensure osmolality reduction does not exceed 3 mOsm/kg/hour to prevent cerebral edema 1, 5
• Track fluid input/output and clinical examination findings 1

Potassium Management During Dextrose Infusion

• Always add 20-30 mEq/L potassium to dextrose-containing fluids once renal function is confirmed 1
• Use 2/3 KCl and 1/3 KPO4 mixture 1
• Never delay insulin while waiting to add dextrose - continue insulin until ketoacidosis resolves 1

Common Pitfalls to Avoid

• Never stop insulin just because glucose normalizes - ketoacidosis takes longer to clear than hyperglycemia 1, 3
• Never exceed osmolality reduction of 3 mOsm/kg/hour, especially in pediatric patients where cerebral edema risk is highest 1
• Never add potassium to IV fluids before confirming adequate urine output and renal function 1
• Never use excessive fluid rates in patients with cardiac or renal compromise - this precipitates pulmonary edema 1
• In pediatric patients, never exceed 50 mL/kg over the first 4 hours 1

Special Considerations

• For patients with chronic kidney disease, reduce standard fluid rates by approximately 50% to prevent volume overload 1
• In euglycemic DKA (SGLT-2 inhibitor use, pregnancy, prolonged fasting), start dextrose-containing fluids immediately alongside insulin 1
• Recent guidelines suggest considering de-escalation of insulin from 0.1 to 0.05 units/kg/hour when glucose drops below 14 mmol/L (252 mg/dL) to reduce hypoglycemia risk 6