A 58-year-old man with a 10-year history of type 2 diabetes mellitus (HbA1c 8.2%) and hypertension (on amlodipine 5 mg daily) presents for elective laparoscopic cholecystectomy. His fasting blood glucose is 156 mg/dL. On examination, BP is 138/88 mmHg, HR 82/min, and BMI 28 kg/m². ECG shows normal sinus rhythm with no ST changes. He denies chest pain, dyspnea, or orthopnea. What is the most appropriate perioperative glucose management strategy for this patient?

Explanation

## Perioperative Glucose Management in Diabetic Patients **Key Point:** Perioperative hyperglycemia increases surgical site infection risk, impairs wound healing, and worsens outcomes. Tight glycemic control (target 140–180 mg/dL) is the evidence-based goal during surgery and immediate postoperative period. ### Rationale for Correct Answer Intravenous insulin infusion with glucose monitoring is the gold standard for perioperative glycemic control because: 1. **Rapid titration:** IV insulin allows minute-to-minute adjustment based on frequent glucose checks (every 1–2 hours intraoperatively). 2. **Avoids hypoglycemia:** Unlike subcutaneous insulin, IV infusion can be stopped immediately if glucose drops. 3. **Predictable pharmacokinetics:** No absorption variability; onset within minutes. 4. **NPO status:** Patient cannot take oral medications; IV route bypasses this constraint. 5. **Stress hyperglycemia:** Surgery triggers catecholamine and cortisol release, raising glucose; IV insulin addresses this dynamically. **Target range 140–180 mg/dL** balances infection prevention (glucose <180 mg/dL) with hypoglycemia avoidance (glucose >140 mg/dL) [cite:American College of Surgeons ACS NSQIP Guidelines]. ### Perioperative Insulin Infusion Protocol | Step | Action | |------|--------| | **Pre-op** | Hold long-acting insulin; hold metformin (renal risk); hold sulfonylureas (hypoglycemia risk) | | **Induction** | Start IV insulin 0.5–1 unit/kg/hr; establish IV dextrose 5% at 100 mL/hr | | **Intra-op** | Check glucose every 1–2 hours; adjust insulin infusion by 0.5–1 unit/hr increments | | **Post-op** | Continue IV insulin until patient tolerates oral intake; resume home regimen when eating | **Clinical Pearl:** Dextrose-containing fluids are essential during IV insulin infusion to prevent hypoglycemia, especially in prolonged procedures. **High-Yield:** Perioperative glucose >250 mg/dL increases infection risk 3-fold; maintain <180 mg/dL intraoperatively. --- ## Why Other Options Are Suboptimal ### Option 0: Continue Home Medications - **Problem:** Patient is NPO; cannot swallow tablets. Metformin increases lactic acidosis risk if renal perfusion drops. No glucose monitoring is inadequate for a diabetic undergoing surgery. ### Option 2: Half-Dose Metformin with Dextrose Fluids - **Problem:** Metformin is contraindicated perioperatively (risk of lactic acidosis with hypoxia/hypotension). Dextrose fluids alone do not provide insulin coverage; glucose will rise uncontrolled. ### Option 3: Subcutaneous Insulin Without Monitoring - **Problem:** Subcutaneous insulin has a 15–30 minute onset and peak effect at 1–2 hours—too slow for rapid intraoperative adjustments. No glucose monitoring violates safe perioperative practice. Risk of both hypo- and hyperglycemia.