What is the appropriate unit of insulin to administer to a patient with severe hyperglycemia (blood sugar level of 577 mg/dL)?

Insulin Dosing for Severe Hyperglycemia (Blood Glucose 577 mg/dL)

For a hospitalized patient with a blood glucose of 577 mg/dL without signs of diabetic ketoacidosis (DKA), administer subcutaneous regular insulin using a correction dose of 10-15 units initially, or calculate 5 units for every 50 mg/dL above 150 mg/dL (which would be approximately 15 units for this glucose level). 1

Initial Assessment Required

Before administering insulin, you must determine:

• Presence of DKA or HHS: Check for ketones, pH, bicarbonate, and mental status changes 2
• Potassium level: Exclude hypokalemia (K+ <3.3 mEq/L) before giving insulin, as insulin will further lower potassium 2
• Patient's eating status: NPO vs. eating determines whether you need basal insulin coverage 1
• Hemodynamic stability: Determines IV vs. subcutaneous route 2

Dosing Algorithm Based on Clinical Scenario

If DKA is Present (pH <7.3, ketones positive, bicarbonate <15 mEq/L):

Moderate to Severe DKA:

• Give IV bolus of regular insulin 0.15 units/kg (approximately 10-12 units for a 70 kg patient) 2, 1
• Follow immediately with continuous IV infusion at 0.1 units/kg/hour (approximately 5-7 units/hour) 2, 1
• This is the preferred approach and should be used in an ICU setting 2

Mild DKA (if subcutaneous route chosen):

• Give initial "priming" dose of 0.4-0.6 units/kg (half IV bolus, half subcutaneous) 2, 1
• Follow with 0.1 units/kg/hour subcutaneously or intramuscularly 2, 1

If No DKA (Simple Hyperglycemia in Hospitalized Patient):

For NPO patients:

• Administer 5 units of regular insulin subcutaneously for every 50 mg/dL above 150 mg/dL 1
• For blood glucose of 577 mg/dL: (577-150)/50 = 8.5, round to 15 units maximum (as protocol caps at 20 units for glucose ≥300 mg/dL) 1
• Repeat every 6 hours as needed 1

For eating patients:

• Use the same correction dose calculation (15 units for this glucose level) 1
• Consider initiating basal-bolus insulin regimen with basal insulin at 0.1-0.2 units/kg/day plus correction doses 2
• Rapid-acting insulin analogs (lispro, aspart, glulisine) can be given every 4 hours as an alternative to regular insulin every 6 hours 1

Critical Monitoring Requirements

• Check blood glucose every 1-2 hours initially until stable, then every 4 hours 2
• Monitor potassium every 2-4 hours during active treatment, as hypokalemia occurs in approximately 50% of cases and severe hypokalemia (<2.5 mEq/L) increases mortality 2
• Check electrolytes, BUN, creatinine every 2-4 hours if treating DKA 2, 1
• Expected glucose reduction: 50-75 mg/dL per hour with appropriate insulin dosing 2, 1

Common Pitfalls to Avoid

• Never give insulin if potassium is <3.3 mEq/L without first repleting potassium, as insulin will drive potassium intracellularly and can cause life-threatening arrhythmias 2
• Do not use sliding scale insulin alone as monotherapy; it is ineffective and should always be combined with basal insulin for eating patients 2, 3
• Do not stop checking glucose frequently once initial correction is achieved; rebound hyperglycemia is common 2
• If glucose doesn't fall by 50 mg/dL in the first hour, verify hydration status and consider doubling the insulin dose 2, 1

When to Add Dextrose

• Once blood glucose falls to 250 mg/dL (or 300 mg/dL in HHS), add dextrose 5-10% to IV fluids while continuing insulin infusion 2, 1
• This prevents hypoglycemia while allowing continued correction of ketosis or metabolic abnormalities 2

Transition Planning

• For patients requiring ongoing insulin after acute correction, calculate total daily dose as 0.5-1 unit/kg/day for maintenance 4
• Split as 50% basal insulin and 50% divided among meals as bolus insulin 2