How do you determine the increase in insulin units based on capillary blood glucose levels?

Insulin Dose Adjustment Based on Capillary Blood Glucose

Insulin dose adjustments should follow a structured algorithm based on capillary blood glucose readings, with basal insulin increased by 2 units every 3 days until fasting glucose targets are reached, and prandial insulin adjusted by 1-2 units or 10-15% based on post-meal readings.

Basal Insulin Titration Algorithm

According to the most recent American Diabetes Association (ADA) guidelines, basal insulin should be titrated using the following approach 1:

• Initial dosing: Start with 10 units per day OR 0.1-0.2 units/kg per day
• Target: Set a fasting plasma glucose (FPG) goal based on individualized glycemic targets
• Adjustment frequency: Increase dose by 2 units every 3 days until FPG goal is reached without hypoglycemia
• Hypoglycemia management: If hypoglycemia occurs, determine the cause; if no clear reason is identified, reduce the dose by 10-20%

Prandial Insulin Titration

For prandial (mealtime) insulin adjustments 1:

• Initial dosing: Start with 4 units per meal or 10% of the basal insulin dose
• Adjustment: Increase by 1-2 units or 10-15% of the dose if post-meal glucose remains elevated
• Monitoring: Evaluate post-meal glucose levels 2 hours after meals
• Hypoglycemia management: If hypoglycemia occurs, reduce the corresponding dose by 10-20%

Practical Implementation

1. Record keeping: Maintain a detailed log of:

   • Pre-meal glucose readings
   • 2-hour post-meal glucose readings
   • Insulin doses administered
   • Carbohydrate intake (if using carbohydrate counting)

2. Pattern recognition: Review 3-7 days of glucose readings to identify patterns before making adjustments

3. Basal-bolus balance: Assess the distribution between basal and prandial insulin

   • Typically, basal insulin should comprise 40-60% of total daily insulin dose
   • Prandial insulin should make up the remaining 40-60% 1

Special Considerations

Accuracy of Capillary Blood Glucose Measurements

• Capillary blood glucose readings may differ from venous plasma glucose values
• When using point-of-care glucometers, capillary samples correlate most closely with laboratory plasma glucose levels 2
• Interpret capillary blood glucose with caution in patients with poor peripheral circulation, dehydration, or shock 1

Common Pitfalls to Avoid

1. Overcorrection: Avoid large insulin dose changes that can lead to glucose fluctuations
2. Fear of hypoglycemia: This often prevents appropriate insulin adjustments 3
3. Ignoring patterns: Making adjustments based on single readings rather than established patterns
4. Delayed adjustments: Waiting too long between dose adjustments when glucose remains consistently elevated
5. Failing to adjust for activity: Not accounting for exercise or physical activity that may require insulin reduction

Algorithm for Specific Situations

For Persistent Hyperglycemia

If glucose readings remain consistently elevated despite basal insulin adjustments:

• Consider adding or increasing prandial insulin coverage
• Evaluate for insulin resistance or inadequate total daily dose
• Assess for concurrent illness or medications affecting glucose levels

For Nocturnal Hypoglycemia

If overnight low glucose readings occur:

• Reduce evening/bedtime basal insulin by 10-20%
• Consider changing the timing of basal insulin administration
• Evaluate for delayed hypoglycemic effect of daytime insulin

For Post-Meal Hyperglycemia

If post-meal glucose excursions are significant:

• Adjust prandial insulin timing (administer 15-20 minutes before meals)
• Adjust insulin-to-carbohydrate ratios if using carbohydrate counting
• Consider using rapid-acting insulin analogs for better post-meal coverage

By following these structured algorithms and regularly reviewing glucose patterns, insulin doses can be systematically adjusted to achieve optimal glycemic control while minimizing the risk of hypoglycemia.