Correction Insulin Dosing for Blood Glucose 540 mg/dL
For an adult with blood glucose 540 mg/dL who is already on a scheduled basal-bolus insulin regimen, administer 4 units of rapid-acting insulin (Humalog/lispro) immediately as a correction dose. 1
Immediate Correction Dose Protocol
- Give 4 units of rapid-acting insulin for pre-meal glucose >350 mg/dL when using a simplified sliding-scale approach as an adjunct to scheduled insulin. 1
- This correction dose must supplement—not replace—scheduled basal and prandial insulin; correction insulin alone is never appropriate as monotherapy. 1
- Administer the correction dose in addition to any scheduled prandial insulin if the reading occurs before a meal. 1
Critical Assessment Before Dosing
- Check for diabetic ketoacidosis (DKA) if glucose >300 mg/dL with symptoms (nausea, vomiting, abdominal pain, altered mental status); obtain urine or blood ketones immediately. 1, 2
- Verify serum potassium ≥3.3 mEq/L before giving any insulin; if K+ <3.3 mEq/L, insulin is absolutely contraindicated and potassium must be repleted first. 1, 2
- If DKA is present, continuous IV insulin infusion is preferred over subcutaneous dosing (0.1 units/kg IV bolus followed by 0.1 units/kg/hour infusion). 1, 2
Underlying Regimen Inadequacy
- A glucose of 540 mg/dL signals complete failure of the current insulin regimen, not merely a need for correction dosing. 1
- For insulin-naive patients with glucose >300 mg/dL, start a basal-plus regimen with total daily dose 0.3-0.5 units/kg/day (50% basal, 50% prandial) rather than relying on correction insulin alone. 1
- Sliding-scale insulin as monotherapy is condemned by all major diabetes guidelines; only 38% of patients achieve mean glucose <140 mg/dL with sliding-scale alone versus 68% with scheduled basal-bolus therapy. 1
Monitoring After Correction
- Recheck glucose 1-2 hours after the correction dose to assess response. 1
- If glucose remains >300 mg/dL after 2 hours, give an additional correction dose and investigate underlying causes (infection, medication non-adherence, DKA). 1
- Never use rapid-acting insulin at bedtime as a sole correction dose because it markedly raises nocturnal hypoglycemia risk. 1
Transition to Scheduled Insulin Therapy
- Calculate total daily insulin needs as 0.4 units/kg (or 0.3 units/kg if high hypoglycemia risk), with 50% as basal insulin and 50% as prandial insulin across three meals. 1
- When basal insulin exceeds 0.5 units/kg/day without achieving targets, add or intensify prandial insulin rather than continuing basal escalation alone. 1
- Continue metformin at maximum tolerated dose (up to 2000-2550 mg/day) when adding insulin; metformin reduces total insulin requirements by 20-30%. 3
Common Pitfalls to Avoid
- Do not delay correction when glucose >250 mg/dL with symptoms; prolonged severe hyperglycemia increases acute complication risk. 1
- Do not rely solely on correction doses without establishing scheduled basal and prandial insulin; this reactive approach perpetuates dangerous glucose fluctuations. 1
- Do not give correction insulin if the patient cannot eat within 1-2 hours; rapid-acting insulin peaks at 1-3 hours and can cause severe hypoglycemia if food is delayed. 4, 5
- For patients already on home insulin doses ≥0.6 units/kg/day, reduce total daily dose by 20% during hospitalization to prevent hypoglycemia. 1