What should be the morning and evening NPH (Novolin N (NPH insulin)) insulin doses and correction scale for a patient with type 2 diabetes mellitus (T2DM) on a norepinephrine (Levophed (norepinephrine)) drip and hydrocortisone (Cortef (hydrocortisone)) 25 mg every 8 hours, with impaired renal function (creatinine 1.14, glomerular filtration rate (GFR) 70), who received continuous renal replacement therapy (CRRT) until yesterday and is scheduled for dialysis today, and has been experiencing hyperglycemia (blood glucose 320-350 mg/dL) despite receiving 30 units of NPH insulin overnight and an additional 17 units of short-acting insulin?

NPH Insulin Dosing for Critically Ill Patient with Steroid-Induced Hyperglycemia

Given this patient's severe hyperglycemia (320-350 mg/dL) despite 30 units NPH plus 17 units short-acting insulin overnight, combined with high-dose glucocorticoids (hydrocortisone 75 mg/day) and vasopressor support, I recommend: AM NPH 40 units, PM NPH 25 units, with an aggressive correction scale of 2 units for every 50 mg/dL above 150 mg/dL.

Rationale for Dose Escalation

• Current insulin requirements are clearly inadequate: The patient received 47 total units overnight yet remained severely hyperglycemic, indicating significant insulin resistance from multiple factors 1, 2

• Glucocorticoid effect is substantial: Hydrocortisone 25 mg every 8 hours (75 mg/day total) creates a hyperglycemic pattern peaking in afternoon/evening, requiring 40-60% higher insulin doses than baseline 1, 2

• Vasopressor-induced insulin resistance: Norepinephrine drips significantly increase insulin requirements through counter-regulatory hormone effects 1

• Continuous tube feeding with 198g carbohydrate: Using the guideline calculation of 1 unit per 10-15g carbohydrate, this alone requires approximately 13-20 units of nutritional coverage 1, 3

Morning NPH: 40 Units

• Morning dosing matches steroid pharmacokinetics: Hydrocortisone administered every 8 hours creates peak hyperglycemia during daytime hours, making morning NPH the preferred approach 2, 1

• Calculation basis: Patient required 47 units overnight with poor control. For steroid-induced hyperglycemia, the morning dose should be higher (approximately 60% of total daily dose) to match the afternoon/evening hyperglycemic peak 2, 3

• Safety consideration with dialysis: Morning administration allows monitoring during dialysis and reduces risk of undetected hypoglycemia during the procedure 4

Evening NPH: 25 Units

• Lower evening dose rationale: Overnight insulin sensitivity typically increases, and the steroid effect wanes by late evening 2, 3

• Renal function consideration: With GFR 70 and recent CRRT discontinuation, insulin clearance may be impaired, increasing hypoglycemia risk overnight 4

• Approximately 40% of total daily dose: This 40:60 evening-to-morning ratio aligns with steroid-induced hyperglycemia patterns 2

Correction Scale (Aggressive)

Blood glucose 150-200 mg/dL: 2 units
Blood glucose 201-250 mg/dL: 4 units
Blood glucose 251-300 mg/dL: 6 units
Blood glucose 301-350 mg/dL: 8 units
Blood glucose >350 mg/dL: 10 units and notify physician 3, 1

• Rationale for aggressive scale: Standard correction scales (1 unit per 50 mg/dL) are insufficient given this patient's demonstrated insulin resistance 3

• Frequency: Administer corrections every 4 hours with rapid-acting insulin (preferred) or every 6 hours with regular insulin 1, 3

Critical Monitoring Protocol

• Check blood glucose every 2-4 hours during the first 24-48 hours after dose adjustment to identify patterns 2, 3

• Target range: 140-180 mg/dL for critically ill patients (less stringent than outpatient targets) 1

• Hypoglycemia protocol: If glucose <70 mg/dL occurs, reduce the corresponding NPH dose by 10-20% immediately 2, 4

• Dialysis day precautions: Monitor glucose hourly during dialysis, as glucose removal during treatment may precipitate hypoglycemia 4

Adjustment Algorithm for Next 48-72 Hours

• If fasting glucose remains >180 mg/dL after 3 days: Increase morning NPH by 4 units (given severity of hyperglycemia, use 4-unit increments rather than standard 2-unit increments) 2, 3

• If afternoon/evening glucose >180 mg/dL: Increase morning NPH by 4 units (as morning NPH peaks 4-6 hours post-administration) 2

• If overnight glucose >180 mg/dL: Increase evening NPH by 2-4 units 2, 3

• If requiring >10 units correction insulin daily: Add 50% of total daily correction insulin to scheduled NPH doses 1, 3

Special Considerations for This Patient

• Tube feeding interruption risk: If tube feeding stops, immediately start 10% dextrose infusion to prevent hypoglycemia, as NPH continues working 12-18 hours 3, 1

• Steroid taper planning: When hydrocortisone is reduced, decrease NPH doses by 20% per steroid dose reduction to prevent hypoglycemia 2

• Vasopressor weaning: As norepinephrine is weaned, insulin requirements will decrease by 20-30%; monitor for improving glucose control 2

• Renal function fluctuation: With GFR 70 and intermittent dialysis, insulin clearance is unpredictable—err on the side of more frequent monitoring rather than aggressive dosing if uncertainty exists 4

Common Pitfalls to Avoid

• Do NOT use bedtime NPH in this patient: With impaired renal function and dialysis, bedtime dosing creates unacceptable nocturnal hypoglycemia risk 4, 5

• Do NOT reduce insulin doses prematurely on dialysis days: Dialysis removes glucose but also creates stress response; maintain scheduled doses unless hypoglycemia occurs 4

• Do NOT use sliding scale alone: Correction insulin without adequate basal coverage perpetuates hyperglycemia 1, 3

• Watch for the "rebound" pattern: 84% of patients with severe hypoglycemia had preceding mild hypoglycemia—any glucose <70 mg/dL requires immediate dose reduction 3, 1