What is the appropriate sliding scale insulin regimen for a patient with hyperglycemia?

Sliding Scale Insulin Protocol for Hyperglycemia Management

For a patient with blood glucose >150 mg/dL, a sliding scale insulin ratio of 1:20 is appropriate, meaning 1 unit of rapid-acting insulin should be administered for every 20 mg/dL above the target blood glucose level. 1

Target Blood Glucose Ranges

The appropriate target blood glucose range depends on the patient's clinical status:

• Critically ill patients: 140-180 mg/dL (7.8-10.0 mmol/L) 1
• Non-critically ill patients: 140-180 mg/dL (7.8-10.0 mmol/L) 1
• Selected patients (e.g., cardiac surgery patients): 110-140 mg/dL (6.1-7.8 mmol/L) if achievable without significant hypoglycemia 1

Implementation of 1:20 Sliding Scale

For a patient with blood glucose >150 mg/dL using a 1:20 ratio:

Blood Glucose (mg/dL)	Insulin Dose (units)
150-170	1 unit
171-190	2 units
191-210	3 units
211-230	4 units
231-250	5 units
251-270	6 units
271-290	7 units
291-310	8 units
>310	Call provider for further instructions

Important Considerations

Limitations of Sliding Scale Alone

• Sliding scale insulin alone is not recommended as the sole insulin regimen for most hospitalized patients with diabetes 1
• It treats hyperglycemia after it occurs rather than preventing it 1
• Should never be used alone in patients with Type 1 diabetes 2

Recommended Comprehensive Approach

For optimal glycemic management:

1. Basal-bolus regimen: Combine sliding scale with basal insulin for better glycemic control 1

   • Basal insulin: 0.1-0.2 units/kg/day for insulin-naive patients 3, 4
   • Prandial insulin: Typically 50-60% of total daily insulin dose divided before meals 5
   • Correction insulin: Using the sliding scale as described above

2. Monitoring frequency:

   • Check blood glucose before meals and at bedtime
   • More frequent monitoring for patients with unstable glucose levels 5

3. Dose adjustments:

   • If 50% of blood glucose readings are above target: Increase basal insulin by 2 units 1
   • If >2 readings/week <80 mg/dL: Decrease basal insulin by 2 units 1

Special Populations

Critically Ill Patients

• Continuous intravenous insulin infusion is preferred over sliding scale for critically ill patients 1, 6
• Target blood glucose 140-180 mg/dL 1
• Transition to subcutaneous insulin when stable with:
  • Stable glucose for 4-6 hours
  • Normal anion gap
  • Hemodynamic stability
  • Stable nutrition plan 1

Older Adults

For older adults, consider a simplified approach:

• May use a more conservative sliding scale: 2 units for glucose >250 mg/dL, 4 units for glucose >350 mg/dL 1
• Higher target ranges may be acceptable (up to 200 mg/dL) in terminally ill patients or those with severe comorbidities 1

Pitfalls to Avoid

1. Relying solely on sliding scale: This reactive approach leads to poor glycemic control and should be combined with basal insulin 1

2. Hypoglycemia risk: Monitor closely for blood glucose <70 mg/dL, especially in older adults and those with renal impairment 1

3. Overbasalization: Continuing to escalate basal insulin without improvement in fasting glucose; consider adding prandial insulin instead 4

4. Inadequate monitoring: Ensure regular glucose monitoring to guide insulin adjustments 5

5. Abrupt discontinuation: Never abruptly stop oral medications when starting insulin due to risk of rebound hyperglycemia 2

The sliding scale approach of 1:20 for glucose >150 mg/dL provides a framework for correction insulin, but should be incorporated into a comprehensive insulin regimen that includes basal insulin for optimal glycemic control and reduced complications.