Overnight Hypoglycemia Management on t:slim Insulin Pump
You need to reduce BOTH your basal rate AND increase your ISF (insulin sensitivity factor) number to make corrections less aggressive. Dropping to 30 mg/dL overnight represents severe hypoglycemia requiring immediate intervention to prevent life-threatening complications 1.
Immediate Basal Rate Adjustment
Reduce your basal rate by 20% immediately 2. With your current basal of 1.0 units/hour, decrease to 0.8 units/hour for the overnight period when hypoglycemia is occurring 2.
- If hypoglycemia occurs without clear cause (such as unusual exercise or missed meals), the standard recommendation is a 10-20% dose reduction 2
- Given the severity of dropping to 30 mg/dL, use the more aggressive 20% reduction 2
- Adjust the basal rate specifically for the time blocks when hypoglycemia occurs, not necessarily the entire 24-hour period 2
ISF (Insulin Sensitivity Factor) Adjustment
Increase your ISF from 50 to approximately 60-65 to make correction doses less potent 3. This means each unit of correction insulin will lower your glucose by less, reducing the risk of overcorrection leading to hypoglycemia 2.
- The ISF determines how much one unit of insulin lowers blood glucose 2
- When correction doses cause hypoglycemia, increase the ISF number by 10-20% 3
- A higher ISF number = less aggressive corrections = lower hypoglycemia risk 3
Critical Monitoring Requirements
- Check blood glucose at 2-3 AM for several nights after making adjustments to verify the changes are adequate 4
- Continue monitoring fasting glucose values to ensure basal insulin adequacy 2
- If hypoglycemia recurs, make additional 10-20% reductions in basal rate 2
Understanding the Distinction
Basal insulin controls overnight and between-meal glucose levels, while ISF controls how aggressively corrections are made 2. Your overnight hypoglycemia suggests both excessive basal delivery AND overly aggressive correction doses if you're using auto-corrections 2.
- Basal rates should be adjusted based on overnight and fasting glucose patterns 2
- ISF should be adjusted when correction doses consistently cause hypoglycemia or fail to bring glucose into target range 3
- These parameters can and should be adjusted independently 2
Common Pitfall to Avoid
Do not wait more than 3 days between adjustments if hypoglycemia persists 3. Severe hypoglycemia at 30 mg/dL requires urgent intervention, and conservative adjustments should be made every 2-3 days until the pattern resolves 2, 4.
- Scrupulous avoidance of hypoglycemia for 2-3 weeks can reverse hypoglycemia unawareness if present 3
- Always carry at least 15 grams of fast-acting carbohydrate for hypoglycemia treatment 3
- Treat hypoglycemia at blood glucose ≤70 mg/dL with 15 grams of fast-acting carbohydrate 3
Advanced Pump Features
If using Control-IQ or Basal-IQ technology on your t:slim X2, these systems should help prevent hypoglycemia through predictive algorithms 5, 6. However, manual basal rate and ISF settings still require optimization as the foundation for these automated features to work effectively 5.