Glucose Infusion Rate Calculation in Neonates

Glucose Infusion Rate (GIR) Calculator

Calculated GIR

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mg/kg/min

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Understanding Glucose Infusion Rate (GIR) in Neonates

The Glucose Infusion Rate (GIR) is a critical metric used in neonatal intensive care units (NICUs) to manage the metabolic needs of newborn infants, particularly those who are premature, small for gestational age, or born to diabetic mothers. GIR measures how many milligrams of glucose an infant receives per kilogram of body weight per minute.

The GIR Formula

To calculate the GIR, the following formula is used:

GIR (mg/kg/min) = (IV Rate (mL/hr) × Dextrose % × 0.166) / Weight (kg)

Alternatively, the math is derived from: (mL/hr × % Dextrose × 1000) / (Weight in kg × 60 × 100).

Why is GIR Monitoring Important?

Neonates have limited glycogen stores and a high brain-to-body mass ratio, making them highly susceptible to hypoglycemia (low blood sugar). Conversely, excessive glucose infusion can lead to hyperglycemia, osmotic diuresis, and hepatic steatosis. Monitoring GIR ensures that the infant receives a steady supply of energy while maintaining blood glucose levels within the target range (typically 45–120 mg/dL).

Normal Ranges for Neonates

• Starting Rate: Most term neonates start at a GIR of 4–6 mg/kg/min.
• Maintenance Range: Preterm infants often require higher rates, ranging from 6–8 mg/kg/min.
• Maximal Oxidation: The maximum glucose oxidation rate is generally around 12–13 mg/kg/min. Exceeding this may cause fat deposition and increased CO2 production.

Practical Example

Suppose you have a neonate with the following profile:

• Weight: 2.5 kg
• Fluid: D10W (10% Dextrose)
• Rate: 15 mL/hr

Step-by-Step Calculation:

1. Multiply Rate by Dextrose Concentration: 15 × 10 = 150
2. Multiply by conversion factor: 150 × 0.166 = 24.9
3. Divide by Weight: 24.9 / 2.5 = 9.96 mg/kg/min