What is the appropriate dosing strategy for basal-bolus insulin therapy in a critically ill adult male patient with significant hyperglycemia, sepsis, and potential renal or hepatic impairment?

Basal-Bolus Insulin Dosing in Critically Ill Patients with Sepsis

Immediate Recommendation: Transition to IV Insulin Infusion

For a critically ill adult male with significant hyperglycemia, sepsis, and potential organ impairment, continuous intravenous insulin infusion is the mandatory approach, NOT subcutaneous basal-bolus therapy. 1, 2

Why IV Insulin is Required in This Context

• Continuous IV insulin infusion is mandatory for hemodynamically unstable patients with hyperglycemia, particularly those on vasopressors 1
• IV insulin is the preferred and guideline-recommended approach for critically ill patients in the ICU setting 1, 2
• Subcutaneous insulin absorption is unpredictable in septic patients due to altered tissue perfusion and edema 2

Target Glucose Range

• Target glucose of 140-180 mg/dL for critically ill patients with sepsis 3, 1
• Initiate insulin therapy when two consecutive blood glucose levels are >180 mg/dL 3
• Avoid targeting euglycemia (80-110 mg/dL) as this substantially increases iatrogenic hypoglycemia risk without mortality benefit 1, 4

IV Insulin Protocol

• Prepare continuous insulin infusion at 1 unit/mL concentration 1
• Prime new tubing with 20 mL waste volume before initiating therapy to prevent insulin adsorption 1
• Monitor point-of-care glucose every 1-2 hours initially, then every 4 hours once stable 3, 1
• Use arterial blood rather than capillary blood for glucose testing if arterial catheters are present 3

---

If Subcutaneous Insulin is Considered (Only After Stabilization)

Only transition to subcutaneous basal-bolus therapy once the patient is hemodynamically stable, off vasopressors, and tolerating oral intake. 1

Initial Dosing Calculation

• For hospitalized patients who are insulin-naive or on low-dose insulin: start with 0.3-0.5 units/kg/day as total daily dose 5, 2
• For patients on high-dose home insulin (≥0.6 units/kg/day): reduce total daily dose by 20% upon hospitalization to prevent hypoglycemia 5
• For high-risk patients (elderly >65 years, renal failure, poor oral intake): use lower doses of 0.1-0.25 units/kg/day 5, 1

Basal-Bolus Split

• Divide total daily dose as 50% basal insulin (glargine once daily) and 50% bolus insulin (rapid-acting before meals, divided equally among three meals) 5, 2
• This 50:50 split is specifically recommended for hospitalized patients requiring basal-bolus therapy 5

Dose Adjustments for Renal/Hepatic Impairment

• For CKD Stage 5 with type 2 diabetes: reduce total daily insulin dose by 50% 5
• For CKD Stage 5 with type 1 diabetes: reduce total daily insulin dose by 35-40% 5
• Insulin clearance decreases with declining kidney function, requiring closer monitoring for hypoglycemia 5
• Titrate conservatively in patients with eGFR <45 mL/min/1.73 m² 5

Titration Protocol

• Adjust basal insulin every 3 days based on fasting glucose patterns, targeting 80-130 mg/dL 5
• Increase by 4 units every 3 days if fasting glucose ≥180 mg/dL 5
• Increase by 2 units every 3 days if fasting glucose 140-179 mg/dL 5
• Adjust bolus insulin by 1-2 units every 3 days based on 2-hour postprandial glucose, targeting <180 mg/dL 5
• If hypoglycemia occurs, reduce the responsible insulin component by 10-20% immediately 5, 6

Monitoring Requirements

• Check point-of-care glucose before each meal and at bedtime for patients eating regular meals 5
• For patients with poor oral intake, check glucose every 4-6 hours 5
• Monitor more frequently (every 1-2 hours) if glucose >250 mg/dL or <70 mg/dL 1

---

Critical Pitfalls to Avoid

• Never use sliding-scale insulin alone as the sole regimen in critically ill patients—it is associated with poor glycemic control and increased complications 1, 2, 7
• Never use premixed insulin (70/30) in the hospital setting—it has unacceptably high rates of hypoglycemia 1
• Never give rapid-acting insulin at bedtime—this significantly increases nocturnal hypoglycemia risk 5
• Never continue subcutaneous insulin in hemodynamically unstable patients—transition to IV insulin immediately 1, 2
• Do not target glucose <140 mg/dL in critically ill septic patients—this increases hypoglycemia risk without benefit 3, 1

---

Special Considerations for Sepsis

• Hyperglycemia in sepsis is driven by counter-regulatory hormones, increased hepatic glucose production, and insulin resistance 8, 9
• Insulin therapy in sepsis may provide anti-inflammatory effects beyond glucose control 8, 9
• Septic patients are particularly susceptible to hypoglycemia due to impaired counter-regulatory responses 8
• The metabolic derangements of sepsis (high glucose, amino acids, free fatty acids) enhance inflammatory signaling, which insulin can modulate 9

---

Transition from IV to Subcutaneous Insulin

• Calculate total daily dose based on average hourly IV insulin rate over the previous 24 hours × 24 1
• Give 50% as basal insulin once daily (evening) and 50% divided equally among three meals as rapid-acting insulin 1
• Administer first subcutaneous dose 2-4 hours before discontinuing IV insulin to prevent rebound hyperglycemia 1
• Reduce calculated total daily dose by 20-50% in high-risk populations (elderly, renal failure, poor intake) 1