What is the role of sliding scale insulin (SSI) in the management of hyperglycemia?

Sliding Scale Insulin in the Management of Hyperglycemia

The sole use of sliding scale insulin (SSI) in the management of hyperglycemia is strongly discouraged and should be avoided as it leads to poor glycemic control and higher complication rates. 1, 2

Limitations of Sliding Scale Insulin

• SSI alone is reactive rather than preventive, treating hyperglycemia after it occurs
• Associated with greater glycemic variability and higher mean blood glucose levels 3
• Leads to increased incidence of hyperglycemic events compared to other insulin regimens 3
• Does not provide basal insulin coverage, which is essential even when patients are not eating
• Meta-analysis of randomized controlled trials showed that SSI provided no benefits in blood glucose control 3

Recommended Insulin Regimens

For Critically Ill Patients:

• Intravenous insulin infusion is the preferred method 1, 2
• Target glucose range: 140-180 mg/dL (7.8-10 mmol/L) 1
• More stringent goals (110-140 mg/dL) may be appropriate for selected patients if achievable without significant hypoglycemia 1

For Non-Critically Ill Patients:

1. Patients with adequate oral intake:

   • Basal-bolus insulin regimen is preferred 1, 2
   • Total daily dose (TDD): 0.3-0.5 units/kg/day 2
   • 50% as basal insulin (once daily long-acting insulin)
   • 50% as prandial insulin (divided into three doses before meals)

2. Patients with poor oral intake or NPO status:

   • Basal plus correction insulin regimen 1
   • Reduced TDD: 0.1-0.15 units/kg/day, primarily as basal insulin 1
   • Supplemental rapid-acting insulin for correction of hyperglycemia >180 mg/dL

Special Considerations for Elderly Patients

• Lower starting insulin doses (0.2-0.3 units/kg/day) are recommended 1, 2
• Higher risk of hypoglycemia with premixed insulin formulations (3x higher rate compared to basal-bolus regimen) 1
• NPH insulin has a peak action 8-12 hours after injection, increasing hypoglycemia risk in patients with poor oral intake 1

Blood Glucose Targets

• Premeal targets: <140 mg/dL (7.8 mmol/L) 1
• Random blood glucose: <180 mg/dL (10.0 mmol/L) 1
• More stringent targets may be appropriate for stable patients with previous tight glycemic control 1
• Less stringent targets may be appropriate for those with severe comorbidities 1

Implementation Strategies

• Use standardized protocols and preprinted order forms to reduce medication errors 4
• One study showed reduction in prescribing errors from 10.3 to 1.2 per 100 SSI patient-days after implementing a standardized protocol 4
• Hyperglycemic episodes decreased from 55.9 to 16.3 per 100 SSI patient-days 4
• Establish a hypoglycemia management protocol for each patient 1

Monitoring Recommendations

• Monitor blood glucose every 4-6 hours when patient is NPO 2
• Monitor before meals and at bedtime for patients who are eating 2
• For IV insulin, monitor every 30 minutes to 2 hours until stable 2
• Adjust insulin doses based on patterns of glycemic control 2

Comparative Outcomes

• Basal-bolus regimens achieve lower fasting blood glucose (10.8 ± 2.3 vs 11.6 ± 3.5 mmol/L) and mean glucose levels (12.3 ± 1.9 vs 12.8 ± 2.2 mmol/L) compared to sliding-scale regimens 5
• No significant difference in the incidence of severe hypoglycemia or length of hospitalization between basal-bolus and sliding-scale regimens 3

In summary, sliding scale insulin should not be used as the sole regimen for managing hyperglycemia. Instead, structured insulin regimens with basal, nutritional, and correction components should be implemented based on the patient's clinical status and nutritional intake to improve glycemic control and reduce complications.