Perioperative Lantus Dosing for Liver Transplant
Give 13-14 units of Lantus (approximately 75% of her usual 18-unit dose) on the evening before surgery.
Rationale Based on Current Guidelines
The most recent ADA Standards of Care in Diabetes (2025) provide clear guidance for perioperative basal insulin management 1. For long-acting basal insulin analogs like Lantus (insulin glargine), the recommendation is to administer 75-80% of the usual dose when patients are NPO for surgery 2, 1.
Specific Dosing Calculation
- Current dose: 18 units daily
- Recommended perioperative dose: 75-80% of 18 units = 13.5-14.4 units
- Practical dose: 13-14 units (round to nearest whole unit)
This dose reduction is supported by evidence showing that a 25% reduction in basal insulin given the evening before surgery achieves better perioperative glucose control (target 100-180 mg/dL) with significantly lower hypoglycemia risk compared to usual dosing 2, 1, 3.
Critical Perioperative Management Points
Timing and Administration
- Administer the reduced Lantus dose at her usual time the evening before surgery
- Continue NPO status after midnight as ordered
- Do NOT hold the basal insulin completely—this is a common error that leads to perioperative hyperglycemia
Monitoring Requirements
- Check blood glucose every 2-4 hours while NPO 2, 1
- Target glucose range: 100-180 mg/dL perioperatively 2, 1, 3
- Tighter targets (80-180 mg/dL) do not improve outcomes and increase hypoglycemia risk 2
Correctional Insulin Coverage
- Use short- or rapid-acting insulin for hyperglycemia while NPO 2, 1
- Basal insulin alone (without correctional coverage) is inadequate for perioperative management 2, 1
- The basal-plus approach (basal insulin + correctional doses) is superior to sliding scale alone for surgical patients 2, 1
Special Considerations for Liver Transplant
High-Risk Surgery Context
Liver transplantation is major surgery with significant metabolic stress. The surgical stress response and counterregulatory hormones will increase insulin resistance and glucose levels 1, 3. This patient will likely require:
- Transition to intravenous insulin infusion intraoperatively and immediately postoperatively
- Higher insulin requirements than baseline due to surgical stress
- Close monitoring for both hyperglycemia and hypoglycemia
Type 2 Diabetes Specificity
Since this is a type 2 diabetes patient (not type 1), she has some endogenous insulin production, which provides a safety margin. However, maintaining basal insulin coverage is still essential to prevent perioperative hyperglycemia, which increases infection risk, mortality, and length of stay 1, 3.
Common Pitfalls to Avoid
- Do NOT completely hold basal insulin - This outdated practice leads to uncontrolled hyperglycemia
- Do NOT give the full 18-unit dose - This increases hypoglycemia risk when NPO
- Do NOT rely on sliding scale insulin alone - Basal insulin is required for adequate glycemic control 2, 1
- Do NOT use NPH insulin dosing guidelines - NPH requires 50% dose reduction; long-acting analogs like Lantus require only 20-25% reduction 4, 2
Postoperative Transition
After surgery, expect transition to IV insulin during the critical postoperative period, then back to subcutaneous insulin once stable and tolerating oral intake. The basal insulin dose will need reassessment based on postoperative glucose patterns and changing clinical status.