What dose of insulin should be given for severe hyperglycemia with a blood glucose level of 571 mg/dL?

Immediate Insulin Management for Blood Glucose 571 mg/dL

For severe hyperglycemia with blood glucose 571 mg/dL, initiate intravenous regular insulin at 0.1 units/kg/hour (approximately 5-7 units/hour for most adults) if the patient is critically ill or has altered mental status; otherwise, start subcutaneous basal-bolus insulin at 0.3-0.5 units/kg/day total daily dose, split 50% basal and 50% prandial insulin. 1, 2

Critical Assessment First

Before determining the insulin regimen, rapidly assess for:

• Diabetic ketoacidosis (DKA) or hyperosmolar hyperglycemic state (HHS): Check for ketones, arterial pH, bicarbonate, and effective serum osmolality 1
• Mental status changes or severe dehydration: These indicate need for intensive care unit admission and IV insulin 1
• Symptomatic hyperglycemia: Polyuria, polydipsia, weight loss, or visual changes 1, 2

Intravenous Insulin Protocol (If Critically Ill)

Use IV regular insulin for patients with altered mental status, severe dehydration, or confirmed DKA/HHS:

• Start continuous IV regular insulin at 0.1 units/kg/hour without an initial bolus in most cases 1
• Target glucose decline of 50-75 mg/dL per hour 1
• If glucose does not fall by 50 mg/dL in the first hour, check hydration status and double the insulin infusion rate hourly until steady decline achieved 1
• Once glucose reaches 250 mg/dL, change IV fluids to 5% dextrose with 0.45-0.75% saline and continue insulin infusion 1
• Transition to subcutaneous insulin only after metabolic stabilization and resolution of acidosis 1

Common pitfall: Do not stop IV insulin abruptly when glucose reaches 250 mg/dL—continue infusion while adding dextrose to prevent rebound hyperglycemia and allow ketone clearance 1

Subcutaneous Insulin Regimen (If Not Critically Ill)

For stable patients without DKA/HHS but with severe hyperglycemia (glucose 571 mg/dL):

Initial Dosing

• Total daily dose: 0.3-0.5 units/kg/day for severe hyperglycemia 1, 2
• Distribution: 50% as basal insulin (insulin glargine once daily) and 50% as prandial insulin (rapid-acting insulin before meals, divided equally among three meals) 1, 2
• Example for 70 kg patient: Total 21-35 units/day → 10-17 units basal insulin + 3-6 units rapid-acting insulin before each meal 2

Aggressive Titration Protocol

• Basal insulin adjustment: Increase by 4 units every 3 days if fasting glucose ≥180 mg/dL 1, 2
• Target fasting glucose: 80-130 mg/dL (4.4-7.2 mmol/L) 1, 2
• Prandial insulin adjustment: Increase by 1-2 units or 10-15% every 3 days based on 2-hour postprandial glucose readings 2

Critical threshold: When basal insulin exceeds 0.5 units/kg/day without achieving targets, intensify prandial insulin rather than continuing to escalate basal insulin alone to avoid "overbasalization" 1, 2

Special Considerations for Hospitalized Patients

If this patient is hospitalized:

• For insulin-naive or low-dose insulin users: Start 0.3-0.5 units/kg/day total, split 50% basal and 50% prandial 2
• For patients on high home insulin doses (≥0.6 units/kg/day): Reduce total daily dose by 20% to prevent hypoglycemia 2
• For high-risk patients (elderly >65 years, renal failure, poor oral intake): Use lower doses of 0.1-0.25 units/kg/day 2
• Target range: 140-180 mg/dL (7.8-10.0 mmol/L) for most hospitalized patients 1

Foundation Therapy

Continue or initiate metformin (unless contraindicated by renal failure, sepsis, or acute illness) at 1000-2500 mg/day total, as it reduces insulin requirements and provides complementary glucose-lowering effects 2, 3

Monitoring Requirements

• During IV insulin: Check blood glucose every 1-2 hours initially, then every 2-4 hours once stable 1
• During subcutaneous insulin titration: Daily fasting blood glucose monitoring is essential 2
• Electrolytes: Check potassium before starting insulin (hold insulin if K+ <3.3 mEq/L) and monitor every 2-4 hours during acute management 1
• Reassess A1C every 3 months during intensive titration 2

Critical Pitfalls to Avoid

• Do not use sliding scale insulin alone for glucose 571 mg/dL—scheduled basal-bolus regimens are superior 1, 2
• Do not delay insulin therapy attempting oral medications first at this glucose level—insulin is the most effective agent when glucose is severely elevated 2
• Do not continue escalating basal insulin beyond 0.5-1.0 units/kg/day without addressing postprandial hyperglycemia with prandial insulin 1, 2
• Do not mix or dilute insulin glargine with other insulins due to its low pH 2