Recommended Insulin Sliding Scale Protocol for Managing Hyperglycemia
For managing hyperglycemia in hospitalized patients, a basal-bolus insulin regimen is strongly recommended over traditional sliding scale insulin alone, as it provides better glycemic control and reduces complications. 1
General Principles
- Target blood glucose range: 140-180 mg/dL (7.8-11.1 mmol/L) for most hospitalized patients 2
- Avoid strict glycemic control (<140 mg/dL) as it increases hypoglycemia risk without mortality benefit 2
- Sliding scale insulin (correctional insulin) alone is ineffective and should not be used as the sole therapy 1, 3
Recommended Insulin Protocol
1. For Non-Critically Ill Patients
Initial Dosing:
- Total Daily Dose (TDD): 0.3-0.5 units/kg/day for insulin-naïve patients 1, 2
- Lower doses (0.2-0.3 units/kg/day) for patients at higher risk of hypoglycemia:
- Elderly patients (>65 years)
- Renal failure
- Poor oral intake 1
- For patients already on insulin at home (≥0.6 units/kg/day), reduce TDD by 20% during hospitalization 1
Distribution:
- 50% as basal insulin: Once or twice daily long-acting insulin (glargine, detemir, or degludec)
- 50% as prandial insulin: Divided into three doses before meals using rapid-acting insulin (aspart, lispro, or glulisine) 2
Correction Scale (to be added to prandial doses):
| Blood Glucose (mg/dL) | Low-Dose Scale | Moderate-Dose Scale | High-Dose Scale |
|---|---|---|---|
| 140-180 | 1 unit | 2 units | 3 units |
| 181-220 | 2 units | 4 units | 6 units |
| 221-260 | 3 units | 6 units | 9 units |
| 261-300 | 4 units | 8 units | 12 units |
| >300 | 5 units | 10 units | 15 units |
- Low-dose: Insulin-sensitive, elderly, renal failure
- Moderate-dose: Most patients
- High-dose: Insulin-resistant patients (requiring >80 units/day) 2
2. For Patients with NPO Status
- Continue basal insulin at 100% of usual dose
- Omit prandial insulin
- Add correction insulin every 4-6 hours 1, 2
- Monitor blood glucose every 4-6 hours 1, 2
3. For Critically Ill Patients
- Continuous intravenous insulin infusion is preferred 4
- Target blood glucose: 140-180 mg/dL 2
- Monitor glucose every 30 minutes to 2 hours until stable 2
- When transitioning to subcutaneous insulin:
- Calculate TDD based on average hourly insulin infusion rate over previous 12 hours
- Multiply by 24 to get estimated daily requirement
- Administer first dose of basal insulin 1-2 hours before stopping IV insulin 1
Daily Insulin Adjustment
- If fasting glucose consistently >140 mg/dL: Increase basal insulin by 10-20% 2
- If pre-meal glucose consistently >180 mg/dL: Increase previous meal's prandial insulin by 10-20% 2
- After hypoglycemia event (<70 mg/dL): Reduce corresponding insulin dose by 20-40% 2
Special Considerations
- For enteral/parenteral nutrition: Use NPH insulin every 12 hours or glargine/degludec daily, plus regular insulin every 6 hours or rapid-acting insulin every 4 hours (starting with 1 unit per 10-15g carbohydrate) 1
- For perioperative management:
- Withhold metformin on day of surgery
- Withhold oral hypoglycemic agents morning of surgery
- Give 60-80% of long-acting insulin dose 1
Common Pitfalls to Avoid
- Using sliding scale insulin alone - This reactive approach leads to poor glycemic control and higher complication rates 1, 3
- Premixed insulin formulations - Associated with unacceptably high rates of hypoglycemia in hospital settings 1
- Targeting strict glycemic control (<140 mg/dL) - Increases hypoglycemia risk without clear benefit 2
- Failing to adjust insulin doses daily - Regular assessment and adjustment is essential for optimal control 2
- Neglecting basal insulin - Even when NPO, patients require basal insulin to prevent hyperglycemia 1
The evidence clearly demonstrates that a physiologic basal-bolus approach with appropriate correction doses is superior to traditional sliding scale regimens, with studies showing improved glycemic control and reduced complications 1, 4, 3.