Peri‑operative Glycemic Management for Valve Surgery

Target Glucose Levels

Maintain blood glucose between 100 – 180 mg/dL (5.6 – 10.0 mmol/L) from induction through the first 4 hours after valve surgery. This range balances hyperglycemia‑related complications with hypoglycemia risk and is endorsed by the American Diabetes Association (ADA) 2024‑2025 guidelines. 1, 3, 2
Avoid tighter targets (e.g., 80 – 110 mg/dL). Evidence shows no mortality benefit and a higher incidence of hypoglycemia when stricter goals are pursued. 1, 4, 3
A broader consensus among multiple diabetes societies supports a 140 – 180 mg/dL target for most surgical patients, reinforcing the ADA range as the optimal window. 5

Aim for a pre‑operative HbA1c < 8 % (<64 mmol/mol) for elective valve procedures; values ≥ 7 % are linked to increased composite morbidity and mortality in cardiac surgery. 1, 3, 2
An HbA1c of 8 % (upper acceptable limit) is associated with higher rates of postoperative infection, wound complications, cardiovascular events, and renal dysfunction. 2
Institutions may implement pre‑operative optimization programs to lower HbA1c before elective surgery, improving outcomes when surgery can be safely delayed. 1, 6, 2

Hold metformin on the day of surgery to reduce the risk of lactic acidosis. 1, 3, 2
Discontinue SGLT2 inhibitors 3‑4 days prior to surgery to prevent euglycemic ketoacidosis. 1, 3, 2
Suspend all other oral glucose‑lowering agents on the morning of surgery. 1, 3, 2
Adjust basal insulin: give 75‑80 % of the usual long‑acting basal insulin dose (or 50 % of NPH) the evening before surgery to avoid hypoglycemia while maintaining target glucose. 1, 3, 2

Glucose monitoring frequency: check capillary or plasma glucose at least every 2‑4 hours while the patient is NPO (nil per os). This applies to all valve surgery patients and those with chronic liver disease. 1, 3, 2
Insulin corrections: use short‑acting or rapid‑acting insulin for any glucose values outside the 100‑180 mg/dL window. 1, 3
Continuous glucose monitoring (CGM) devices should not be used alone for intra‑operative glucose assessment; confirm values with standard point‑of‑care testing. 1, 3, 2

Implement a basal‑bolus insulin regimen (basal insulin plus scheduled prandial/bolus doses) rather than a correction‑only sliding‑scale. This strategy yields superior glycemic control and lowers peri‑operative complication rates. 1, 3, 6
Reactive sliding‑scale insulin alone is associated with poorer glycemic outcomes and higher complication rates compared with basal‑bolus therapy. 1, 3, 6

Impaired hepatic glucose production in chronic liver disease increases the risk of intra‑operative hypoglycemia; therefore, more frequent glucose checks are warranted. 3
Altered insulin clearance may necessitate dose adjustments; consider a 25 % reduction of basal insulin the night before surgery. 2
Continue the 2‑4 hour monitoring interval while NPO and apply the basal‑insulin reduction strategy to mitigate hypoglycemia risk. 1, 3