What it is
Glucose infusion rate (GIR) is the amount of dextrose a neonate receives per kilogram per minute, expressed in mg/kg/min. It is the single most useful number when managing neonatal glucose homeostasis: it lets you titrate against hypoglycemia, plan parenteral nutrition, and recognise hyperinsulinism (which often demands a GIR well above the physiologic ceiling).
The method
The core relationship is:
$$ GIR\ (mg/kg/min) = \frac{dextrose\ %\ \times\ rate\ (mL/hr) \times 10}{60 \times weight\ (kg)} $$
Equivalently, total daily glucose load (mg/day) = GIR × weight × 1440. The Doctaverse calculator works the problem in reverse: you give it weight, day of life and a target GIR, and it returns the daily glucose mass, the day-of-life fluid allowance (mL/kg/day), standard electrolyte additive volumes, and the feasible dextrose-strength blends (e.g. D25 + D10) that hit your target inside that fluid budget. If a blend can’t be made within the available volume it is flagged “not feasible”.
When to use it
- Hypoglycemia: a healthy term neonate’s endogenous hepatic glucose output is roughly 4–8 mg/kg/min; start IV dextrose in that range and titrate up.
- Parenteral nutrition: setting and advancing the glucose component day by day.
- Suspected hyperinsulinism: a GIR requirement >8–10 mg/kg/min to maintain euglycemia is a red flag.
Worked example
A 2 kg neonate on day 3 with a target GIR of 6 mg/kg/min:
- Daily glucose = 6 × 2 × 1440 = 17,280 mg/day ≈ 17.3 g/day
- Day-3 fluid (>1.5 kg) ≈ 90 mL/kg/day × 2 = 180 mL/day
- After subtracting standard NaCl/KCl/Ca additive volumes, the remaining volume is partitioned between two dextrose strengths to deliver that glucose mass — the calculator prints the exact mL of each.
Pitfalls
- Peripheral ceiling. Dextrose >12.5% (D12.5W) is hyperosmolar and must run through a central line; peripheral extravasation of concentrated dextrose causes tissue necrosis.
- Additive concentrations vary. The electrolyte volumes assume your unit’s standard stock strengths — confirm mEq/mL before adding.
- A high GIR is a diagnosis, not just a number. If you keep climbing past ~10 mg/kg/min, investigate hyperinsulinism rather than simply chasing the glucose.
- Day-of-life fluids climb. The mL/kg/day allowance rises over the first week, so the same target GIR needs a different dextrose strength on day 1 versus day 5 — recompute rather than reusing yesterday’s bag.
- GIR titrates glucose delivery; it does not replace bedside glucose monitoring. Recheck glucose after any change and treat the infant, not the infusion.
Run it: Glucose Infusion Rate (GIR) & TPN
Decision support for qualified clinicians only — verify against current primary guidelines and your clinical judgement.