From the Guidelines
Postoperative hyperglycemia should be managed promptly with insulin therapy to maintain blood glucose levels between 140-180 mg/dL in most surgical patients. This approach is supported by the most recent evidence from the Diabetes Care in the Hospital standards of care in diabetes-2023 1. For mild elevations (180-250 mg/dL), subcutaneous insulin using a basal-bolus approach is appropriate, typically starting with 0.2-0.5 units/kg/day divided into basal insulin (glargine or detemir) and prandial insulin (lispro, aspart, or regular insulin).
Key Considerations
- For severe hyperglycemia (>250 mg/dL) or in critically ill patients, continuous intravenous insulin infusion starting at 1-2 units/hour with hourly glucose monitoring is recommended 1.
- Blood glucose should be checked every 4-6 hours for subcutaneous regimens and more frequently when initiating therapy.
- Hyperglycemia after surgery is common due to surgical stress triggering cortisol and catecholamine release, which increase insulin resistance and hepatic glucose production.
- Uncontrolled postoperative hyperglycemia is associated with increased risk of surgical site infections, delayed wound healing, longer hospital stays, and higher mortality rates.
Perioperative Care
According to the standards of care in diabetes-2023 2, a preoperative risk assessment should be performed for people with diabetes who are at high risk for ischemic heart disease and those with autonomic neuropathy or renal failure. The A1C target for elective surgeries should be <8% (63.9 mmol/L) whenever possible. The target range for blood glucose in the perioperative period should be 100–180 mg/dL (5.6–10.0 mmol/L) within 4 h of the surgery.
Management Strategies
- Metformin should be held on the day of surgery.
- SGLT2 inhibitors must be discontinued 3–4 days before surgery.
- Hold any other oral glucose-lowering agents the morning of surgery or procedure and give half of NPH dose or 75–80% doses of long-acting analog or insulin pump basal insulin based on the type of diabetes and clinical judgment.
- Monitor blood glucose at least every 2–4 h while the individual takes nothing by mouth and dose with short- or rapid-acting insulin as needed.
From the FDA Drug Label
Hyperglycemia (too much glucose in the blood) may develop if your body has too little insulin Hyperglycemia can be brought about by any of the following: Omitting your insulin or taking less than your doctor has prescribed. Eating significantly more than your meal plan suggests. Developing a fever, infection, or other significant stressful situation. In patients with type 1 or insulin-dependent diabetes, prolonged hyperglycemia can result in DKA (a life-threatening emergency)
Postoperative hyperglycemia can occur due to various factors such as:
- Omitting or taking less insulin than prescribed
- Eating more than the meal plan suggests
- Developing a fever, infection, or other stressful situation It is essential to monitor blood glucose levels frequently, especially in postoperative patients, to avoid hyperglycemia and its complications, such as diabetic ketoacidosis (DKA) 3.
From the Research
Postoperative Hyperglycemia
- Postoperative hyperglycemia has been associated with poor surgical outcomes 4
- Intraoperative glucose management can affect postoperative glucose levels, with higher intraoperative glucose levels associated with higher postoperative glucose levels 4
- The optimal glycemic threshold for initiating insulin therapy is currently unknown, but initiating insulin infusion when glucose level exceeds 140 mg/dL may be associated with lower postoperative glucose levels and fewer incidences of postoperative hyperglycemia 4
Risk Factors for Postoperative Hyperglycemia
- Diabetes status and intraoperative steroid use have a positive effect on elevated postoperative glucose levels 4
- Body mass index and procedure duration can interact with intraoperative glucose management to affect postoperative glucose levels 4
- Hemoglobin A1C level is associated with elevated risk of hyperglycemia and adverse outcomes 5
Management of Postoperative Hyperglycemia
- Screening at-risk patients, using preoperative oral hypoglycemics and home insulin, and selecting appropriate anesthetic type and medication can aid in optimal perioperative care 5
- Blood glucose testing and treatment for hyperglycemia in the operating room are recommended 5
- Insulin therapy should be administered to treat hyperglycemia at ≥140 mg/dL when fasting and ≥180 mg/dL postprandially 6
- Continuous subcutaneous insulin pump therapy and continuous glucose monitoring may be useful in detecting and correcting aberrations in blood glucose levels 6
Insulin Formulations and Postprandial Hyperglycemia
- Faster-acting insulin formulations may provide better postprandial glucose control than traditional insulin formulations, regardless of the glycemic index of the meal 7
- Fiasp provides noninferior postprandial glucose control in hospitalized patients with type 2 diabetes when compared to Novolog, with no increase in rates of hypoglycemia 8