Blood Glucose Just Above 70 mg/dL During Surgery: Not Acceptable
No, a blood glucose level just above 70 mg/dL is not acceptable during surgery—the recommended perioperative target range is 100–180 mg/dL (5.6–10.0 mmol/L). 1
The Evidence-Based Target Range
The most recent 2024 American Diabetes Association guidelines explicitly state that blood glucose goals in the perioperative period should be 100–180 mg/dL within 4 hours of surgery 1. This represents a deliberate shift away from tighter glycemic control that includes values in the 70s.
Why Not Lower Than 100 mg/dL?
The guidelines specifically warn that stricter perioperative glycemic goals (such as 80–180 mg/dL) are not advised, as they do not improve outcomes and are associated with more hypoglycemia 1. The 2023 ADA guidelines similarly concluded that targets tighter than 80–180 mg/dL increase hypoglycemia risk without benefit 2.
A blood glucose "just above 70 mg/dL" (say, 75-85 mg/dL) falls below the recommended 100 mg/dL lower threshold and creates several problems:
- Hypoglycemia risk: Values in the 70s provide minimal buffer before true hypoglycemia (<70 mg/dL), which is particularly dangerous during surgery when patients cannot report symptoms
- Surgical stress response: Counterregulatory hormone release during surgery can cause rapid glucose fluctuations, making borderline-low values precarious
- No outcome benefit: Research shows that achieving near-normoglycemia during surgery doesn't improve morbidity or mortality compared to the 100-180 mg/dL range
Practical Intraoperative Management
During surgery, you should:
- Monitor blood glucose every 1-2 hours during the procedure 3
- Treat if glucose drops below 100 mg/dL by reducing insulin infusion or providing additional glucose
- Avoid aggressive correction of values between 100-180 mg/dL, as this increases hypoglycemia risk
- Use continuous IV insulin protocols for major surgery, adjusting based on the 100-180 mg/dL target 1
Common Pitfall to Avoid
The most critical error is applying ICU-style tight glycemic control (targeting 80-110 mg/dL) to the operating room. This approach, popularized by early van den Berghe studies, has been definitively shown to increase hypoglycemia without improving surgical outcomes 3, 4. The NICE-SUGAR trial demonstrated increased mortality with intensive glucose control in critically ill patients 4.
The Bottom Line
A glucose level just above 70 mg/dL during surgery is too low and should prompt intervention. Aim for 100-180 mg/dL throughout the perioperative period. This moderate target reduces surgical complications from hyperglycemia while maintaining a safe margin above hypoglycemia—a balance that improves both morbidity and mortality outcomes 1, 5.