Hyperglycemia Cutoff for Term Neonates
For term neonates, hyperglycemia is defined as blood glucose >8 mmol/L (145 mg/dL), which should be avoided due to associations with increased morbidity and mortality, and treatment with insulin should be initiated when repetitive blood glucose levels exceed 10 mmol/L (180 mg/dL) after reasonable adjustment of glucose infusion rate has been insufficient. 1, 2
Diagnostic Thresholds
The ESPGHAN/ESPEN/ESPR/CSPEN guidelines establish a two-tiered approach to hyperglycemia in neonates:
- Avoidance threshold: Blood glucose >8 mmol/L (145 mg/dL) should be avoided in neonatal ICU patients as it is associated with increased morbidity and mortality 1, 2
- Treatment threshold: Repetitive blood glucose levels >10 mmol/L (180 mg/dL) warrant insulin therapy, but only after reasonable adaptation of glucose infusion rate has been insufficient 1, 2
The most common definition used in clinical practice is blood glucose exceeding 10 mmol/L (180 mg/dL), which has been consistently associated with increased morbidity in preterm infants 1
Measurement Considerations
Blood glucose measurements should be performed using blood gas analyzers with glucose modules rather than handheld glucometers for optimal accuracy in neonates. 1, 2, 3
Critical factors affecting measurement accuracy include:
- High hemoglobin levels can interfere with handheld meter readings 1, 2, 4
- High bilirubin levels can cause measurement errors 1, 2
- Handheld glucose meters are less accurate in critically ill neonates despite their convenience 1
- Standard laboratory testing may yield falsely low results due to ongoing glycolysis if pre-analytical guidelines are not followed 1
Management Algorithm
Step 1: Adjust Glucose Infusion Rate First
Before considering insulin therapy, optimize the glucose infusion rate:
- Term neonates Day 1: Target 2.5-5 mg/kg/min (3.6-7.2 g/kg/day) 1, 2, 3
- Term neonates Day 2 onwards: Target 5-10 mg/kg/min (7.2-14.4 g/kg/day) 1, 2, 3
- Maximum: Do not exceed 12 mg/kg/min (17.3 g/kg/day) 1, 3
- Minimum: Generally not lower than 2.5 mg/kg/min (3.6 g/kg/day) 1, 3
Step 2: Insulin Therapy (If Glucose Adjustment Fails)
Initiate insulin therapy only when repetitive blood glucose levels remain >10 mmol/L (180 mg/dL) despite reasonable glucose infusion rate adjustment. 1, 2
- Start with a low insulin dose to minimize hypoglycemia risk 1, 2
- Insulin therapy is effective but increases the incidence of hypoglycemia 1, 2
- There is no evidence supporting tight blood glucose management in the NICU 1
Special Circumstances
During acute illness (infection or sepsis), temporarily reduce glucose infusion to Day 1 rates and guide management by blood glucose levels. 1, 3
Hyperglycemia may also result from:
- Excessive glucose administration (iatrogenic) 5
- Inability to suppress hepatic glucose production 5
- Insulin resistance or glucose intolerance, particularly in preterm neonates 5
Critical Pitfalls to Avoid
- Avoid aggressive insulin therapy: Start with low doses as insulin therapy increases hypoglycemia risk 1, 2
- Do not rely solely on handheld glucometers: Use blood gas analyzers for accurate measurements 1, 2, 3
- Prevent hypoglycemia: Repetitive and/or prolonged hypoglycemia ≤2.5 mmol/L (45 mg/dL) must be avoided as it can lead to adverse outcomes 1, 2, 4
- Individualize carbohydrate intake: Especially in newborns with specific problems like severe perinatal asphyxia, where concomitant hypoglycemia may exacerbate brain damage 1