Hyperglycemia is common in very low birth weight (VLBW) infants during the first postnatal week and is associated with important neonatal complications.
Goals:
GIR reduction is considered for glucose persistently >150 mg/dL. Insulin is considered for glucose persistently >180 mg/dL despite low GIR. Target during insulin therapy: 130–180 mg/dL.
Additional complications associated with neonatal hyperglycemia:
| Mechanism | Explanation |
|---|---|
| Limited insulin secretion | Preterm pancreatic beta-cell immaturity; may not produce enough insulin for the glucose load |
| Stress catecholamines | Growth-restricted infants and hypoxia-exposed infants secrete more catecholamines → glycogenolysis and gluconeogenesis |
| Increased hepatic glucose production | Cortisol, glucagon, and growth hormone increase hepatic glucose output |
| Medications | Catecholamine infusions and glucocorticoids (e.g., dexamethasone) worsen hyperglycemia |
| Slow feeding advancement | Delayed or slow enteral feeds remove the glucose-regulatory benefits of gut hormones and incretin effect |
| Prevention Step | Practical Meaning |
|---|---|
| Start enteral feeding early when clinically appropriate | Early feeds activate gut hormones and incretin effects that promote glucose regulation |
| Advance enteral feeds as tolerated | Better enteral nutrition supports glucose homeostasis and reduces reliance on IV glucose |
| Optimize protein intake | Baylor protein goal: 3.5–4 g/kg/day — adequate protein is anabolic and insulin-sensitizing |
| Advance glucose infusion slowly | Avoid abrupt high-GIR exposure; start conservatively and increase stepwise |
Two main treatment strategies exist:
In the short term, reducing GIR is preferred before insulin because insulin increases the risk of hypoglycemia. Use insulin only after GIR has already been appropriately reduced.
Prolonged glucose restriction is harmful to growth. Short-term GIR reduction (to a minimum of 3.5 mg/kg/min) is preferred before starting insulin, but do not sacrifice caloric intake beyond this threshold just to lower glucose.
| Item | Recommendation |
|---|---|
| Medication | Regular insulin |
| Bolus dose | 0.05–0.1 units/kg |
| Administration | Infuse over 15 minutes without IV extension tubing |
| Follow-up | Start continuous infusion if acceptable glucose values are not achieved |
| Monitoring | Check glucose every 30–60 minutes after insulin doses until stable |
| Subcutaneous insulin | Avoid — absorption is unpredictable in neonates |
Insulin adsorbs to IV tubing — flush the line per unit protocol before starting to saturate binding sites. Insulin onset can be highly variable depending on tubing dead space between the insulin line joining the primary IV line.
Close glucose monitoring must continue even after target glucose is achieved.
| Situation | Action |
|---|---|
| Glucose is rapidly falling | Decrease insulin infusion rate |
| Blood glucose <100 mg/dL | Stop insulin infusion and monitor glucose closely until stable |
| During insulin infusion | Monitor serum potassium frequently (insulin drives K⁺ intracellularly → hypokalemia) |
| Initial dose vs. maintenance | The initial insulin dose to reach target may be higher than the dose needed to maintain target — watch for overshooting |
Once effective enteral feeding is established, insulin secretion and glucose regulation typically improve. Plan to wean insulin as enteral feeding advances.
| Mistake | Better Action |
|---|---|
| Treating one high glucose value aggressively | Confirm persistence; review GIR, stress, medications, and feeds before acting |
| Reducing glucose too far (below D5 or GIR <3.5) | Do not reduce below D5 or GIR <3.5 mg/kg/min solely to correct hyperglycemia — growth suffers |
| Using insulin before reducing an excessive GIR | Reduce GIR first — insulin carries hypoglycemia risk; reserve it for persistent hyperglycemia at low GIR |
| Giving subcutaneous insulin | Avoid — neonatal subcutaneous absorption is unpredictable; use IV only |
| Not accounting for IV tubing delay | Flush tubing per protocol; insulin onset can be delayed by tubing dead space |
| Continuing insulin during rapid glucose fall | Decrease insulin rate if glucose is falling rapidly; stop if <100 mg/dL |
| Forgetting potassium monitoring | Monitor serum potassium frequently during insulin therapy — insulin causes hypokalemia |
"High blood sugar is common in very small premature babies because their bodies may not yet make or use insulin normally."
"We usually first adjust the amount of sugar in the IV fluid to a lower level while continuing to support growth and nutrition."
"If the blood sugar stays very high despite lowering the IV sugar, we may carefully use small amounts of insulin with very close monitoring every 30 minutes."
"Once feeding improves, high blood sugar usually gets better on its own."