1. Insulin Infusion Weaning Strategies

Once glycemic control and the patient’s underlying inflammatory status stabilize, a stepwise taper of the intravenous (IV) insulin infusion is critical. This methodical approach reduces the risk of rebound hyperglycemia and iatrogenic hypoglycemia, facilitating a smooth transition to the next phase of care.

Criteria for Initiation of Weaning

A readiness assessment should be performed before starting the taper. Key criteria include:

• Glycemic Stability: Blood glucose (BG) maintained within the target range (e.g., 140–180 mg/dL) for at least 6 to 12 hours, with no readings below 140 mg/dL or above 180 mg/dL.
• Inflammatory Markers: A clear downward trend in C-reactive protein (CRP) or procalcitonin suggests resolving inflammation and improving insulin sensitivity.
• Clinical Factors: Decreasing vasopressor requirements, improving renal and hepatic function, stable nutrition orders, and the absence of new infections or initiation of high-dose steroids.
• Monitoring Capacity: Ensure point-of-care (POC) BG testing can be performed every 1 to 2 hours during the weaning phase.

Stepwise Dose Reduction Algorithms

The goal is to find the lowest effective infusion rate before transitioning. A common approach involves:

• Decrease the infusion rate by 10–20% every 1–2 hours if BG remains within target.
• If two consecutive readings are <140 mg/dL, reduce the rate by 50%.
• If BG is consistently in the lower end of the target range (e.g., 140–160 mg/dL), reduce the rate by 33%.
• Coordinate with the nutrition team to maintain consistent enteral or parenteral nutrition rates during the initial taper to isolate the effects of insulin changes.
• The endpoint for cessation is typically when the infusion rate is less than 1 unit/hour and the patient is on a stable nutrition plan.

2. Conversion to Enteral and Subcutaneous Insulin

A successful transition from IV to subcutaneous (SQ) insulin requires careful calculation and timing. The primary strategy involves overlapping the administration of long-acting (basal) insulin with the IV infusion and calculating the initial SQ dose based on the patient’s recent 24-hour IV insulin requirement.

Calculating Transition Doses

The most common method uses a percentage of the total IV insulin infused over the last stable 24-hour period. A reduction factor of 50–70% is applied to account for improved insulin sensitivity as the critical illness resolves.

• Total Daily IV Dose (TDD): Sum the total units of IV insulin infused over the preceding 24 hours.
• Basal Insulin Dose: Calculate 50–70% of the TDD. This is given as a single daily injection of a long-acting insulin analog (e.g., glargine, detemir).
• Prandial (Nutritional) Insulin: Approximately 50% of the calculated *basal* dose, divided evenly among meals and administered as a rapid-acting analog (e.g., lispro, aspart).
• Correctional Insulin: Use the “1800-Rule” for a sensitivity factor: 1800 ÷ TDD = the expected mg/dL drop in BG per 1 unit of rapid-acting insulin.

Timing of Overlap and Monitoring

Proper timing is essential to prevent gaps in insulin coverage. Administer the first dose of basal SQ insulin 2 to 4 hours before discontinuing the IV infusion. This overlap accounts for the pharmacokinetic lag of long-acting insulins. During this transition, monitor BG hourly, then every 2–4 hours for the first 24 hours post-transition.

Managing Enteral Nutrition Changes

Interruptions in enteral nutrition are common and require proactive insulin adjustments:

• Short Pause (<1 hour): No change to basal insulin. Consider reducing the next prandial dose by 50% if the feed is expected to resume shortly.
• Prolonged Pause (>4 hours): Hold all prandial doses. Maintain the basal insulin dose to cover basal metabolic needs and prevent fasting hyperglycemia.
• Electrolyte Management: Maintain serum potassium (K⁺) > 4.0 mEq/L. Hypokalemia can impair insulin secretion, while its correction can enhance insulin sensitivity, increasing hypoglycemia risk.

3. Mitigation of Post-ICU Dysglycemia Sequelae

Dysglycemia (both hyperglycemia and hypoglycemia) is a significant contributor to Post-Intensive Care Syndrome (PICS), which encompasses long-term cognitive, psychological, and physical impairments. Proactive identification of high-risk patients and implementation of bundled care can mitigate these sequelae.

Identifying High-Risk Phenotypes and the ABCDEF Bundle

Patients at high risk for post-ICU complications often exhibit significant glycemic variability. Key features include prolonged periods of hyperglycemia (BG > 145 mg/dL), any history of severe hypoglycemia, and a high BG coefficient of variation (>20%). The ABCDEF bundle provides a framework for holistic care that indirectly and directly improves glycemic homeostasis.

Early Mobilization, Nutrition, and Psychosocial Support

• Mobilization: Progressing from passive range of motion to active sitting and ambulation within 48 hours of stability is crucial. Early mobility enhances peripheral glucose uptake by muscles, directly improving insulin sensitivity. Insulin doses may need adjustment to account for exercise-induced hypoglycemia.
• Nutrition: High-protein enteral formulas (1.2–2.0 g/kg/day) help preserve lean body mass, which is essential for maintaining glycemic homeostasis.
• Psychosocial Support: Engaging family and implementing delirium prevention strategies can stabilize the neuroendocrine stress axis, reducing the release of counter-regulatory hormones like cortisol that drive hyperglycemia.

4. Medication Reconciliation and Discharge Counseling

A meticulous medication reconciliation and structured patient education process are the final, vital steps to ensure a safe transition from hospital to home and minimize the risk of readmission due to glycemic excursions.

Comprehensive Review of All Antihyperglycemic Agents

A thorough review must identify and resolve potential discrepancies. Pay close attention to:

• Insulin Formulations: Confirm the exact name, dose, timing, and delivery device (pen vs. vial/syringe) for all basal, prandial, and correctional insulins.
• Oral Agents:
  • Metformin: Should remain held if eGFR < 30 mL/min/1.73m² or if hemodynamic instability persists.
  • Sulfonylureas: Pose a high risk of prolonged hypoglycemia; strongly reconsider their use, especially in the elderly or those with renal impairment.
  • DPP-4 Inhibitors / GLP-1 RAs: Can be safely resumed once oral intake is stable and consistent.
  • SGLT2 Inhibitors: Avoid in patients who are hypotensive or volume-depleted. Counsel extensively on the risk of euglycemic diabetic ketoacidosis (DKA), especially during illness.
• Common Pitfalls: Watch for unintentional omissions of home medications, therapeutic duplications, and failure to restart agents that were appropriately held during the acute ICU stay.

Patient/Caregiver Education

Education should be interactive and confirm understanding. Key topics include:

• Injection Technique: Demonstrate proper use of an insulin pen or vial/syringe, site rotation, and correct storage of insulin.
• Self-Monitoring of Blood Glucose (SMBG): Teach the frequency (e.g., pre-meal and bedtime), proper technique, and how to log results.
• Hypo/Hyperglycemia Management: Review the specific signs and symptoms, “sick day” rules, and clear protocols for when to self-treat versus when to seek emergency medical care.
• Teach-Back Method: Use the teach-back method to ensure comprehension and provide a written action plan and glucose logs for the patient to take home.