How to adjust the insulin regimen for a patient with type 1 diabetes mellitus (T1DM) undergoing Open Reduction Internal Fixation (ORIF) for hip fracture under general anesthesia, who is currently on glargine (insulin glargine) and insulin lispro (lispro), with a low-dose sliding scale?

From the Guidelines

For a patient with type 1 diabetes mellitus undergoing ORIF for hip fracture under general anesthesia who is on glargine and lispro with a low-dose sliding scale, I recommend continuing the basal insulin (glargine) at 75% of the usual dose the night before and morning of surgery, which is approximately 18.75 units for this patient, while holding the bolus insulin (lispro) on the day of surgery. This approach is based on the most recent evidence from 1, which suggests that a reduction of 25% of basal insulin given the evening before surgery is more likely to achieve perioperative blood glucose goals with a lower risk for hypoglycemia.

Key Considerations:

• Intraoperatively, blood glucose should be monitored hourly, aiming for levels between 100-180 mg/dL, as recommended by 1.
• If glucose exceeds 180 mg/dL, start an insulin infusion at 1-2 units/hour, titrating as needed, to prevent severe hyperglycemia.
• Postoperatively, resume the patient's usual insulin regimen once they begin eating, with potential adjustments based on nutritional intake and activity level, as suggested by 1.
• If the patient remains NPO, continue with 75% of the basal insulin dose and implement a hospital glucose management protocol, maintaining IV fluids with dextrose if needed to prevent hypoglycemia.

Rationale:

The reduction in basal insulin accounts for decreased caloric intake and increased insulin sensitivity due to fasting, while the temporary suspension of bolus insulin prevents hypoglycemia when the patient isn't eating. Close monitoring is essential as surgical stress can increase glucose levels through stress hormone release, while anesthesia and reduced activity may increase insulin sensitivity, as noted in 1. By following this approach, we can balance the need to prevent severe hyperglycemia while minimizing hypoglycemia risk during the perioperative period, ultimately prioritizing the patient's morbidity, mortality, and quality of life. Some key points to consider include:

• The A1C goal for elective surgeries should be <8% (<64.0 mmol/L) whenever possible, as recommended by 1.
• Stricter perioperative glycemic goals are not advised, as they may not improve outcomes and are associated with increased hypoglycemia, as noted in 1.
• Basal insulin plus pre-meal short- or rapid-acting insulin (basal-bolus) coverage has been associated with improved glycemic outcomes and lower rates of perioperative complications, as suggested by 1.

From the FDA Drug Label

Dosage adjustments may be needed with changes in physical activity, changes in meal patterns (i.e., macronutrient content or timing of food intake), during acute illness, or changes in renal or hepatic function. Dosage adjustments should only be made under medical supervision with appropriate glucose monitoring [see Warnings and Precautions (5.2)].

The patient's insulin regimen may need to be adjusted due to the upcoming surgery and general anesthesia. Key considerations include:

• Physical activity: The patient's physical activity level will likely decrease after surgery, which may affect insulin needs.
• Meal patterns: The patient's meal schedule and content may change during hospitalization, impacting insulin requirements.
• Acute illness: The patient's surgical procedure and potential post-operative complications may influence insulin needs.
• Glucose monitoring: Close monitoring of blood glucose levels is crucial to guide insulin dosage adjustments.

Recommendations:

• Closely monitor the patient's blood glucose levels during the perioperative period.
• Adjust the insulin regimen as needed to maintain adequate glycemic control, considering the patient's individual needs and the potential impact of surgery and anesthesia on glucose metabolism.
• Consider consulting with an endocrinologist or a diabetes specialist for guidance on managing the patient's diabetes during the hospital stay 2.

From the Research

Adjusting Insulin Regimen for Type 1 Diabetes Mellitus Patient Undergoing ORIF

To adjust the insulin regimen for a patient with type 1 diabetes mellitus (T1DM) undergoing Open Reduction Internal Fixation (ORIF) for hip fracture under general anesthesia, consider the following:

• The patient's current insulin regimen consists of 25 units of glargine daily, insulin lispro based on carbohydrate intake, and a low-dose sliding scale three times daily.
• According to 3, good postoperative glucose control reduces the risk of in-hospital death and shortens length of stay, and insulin is the mainstay of perioperative glucose management.
• A basal-bolus insulin regimen, as studied in 4, improved glycemic control and reduced hospital complications compared to a sliding scale regimen in general surgery patients with type 2 diabetes.

Considerations for Insulin Adjustment

When adjusting the insulin regimen, consider the following:

• The use of glargine insulin, as studied in 5, effectively managed blood glucose levels and reduced postoperative morbidity in patients with diabetes undergoing off-pump coronary artery bypass grafting.
• The estimation formulas for once-nightly insulin glargine and premeal insulin lispro, as described in 6, can be used to guide dosing adjustments.
• Intraoperative glucose monitoring, as emphasized in 7, is crucial for diabetic patients receiving insulin, and a perioperative systems design can improve intraoperative glucose monitoring and reduce surgical site infections.

Key Points for Insulin Regimen Adjustment

Key points to consider when adjusting the insulin regimen include:

• Maintaining good postoperative glucose control to reduce the risk of in-hospital death and shorten length of stay 3.
• Using a basal-bolus insulin regimen to improve glycemic control and reduce hospital complications 4.
• Adjusting insulin doses based on estimation formulas and individual patient needs 6.
• Ensuring regular intraoperative glucose monitoring to guide insulin adjustments and reduce the risk of surgical site infections 7.