GIR calculator (Glucose Infusion Rate)

The calculation evaluates the rate of intravenous fluid administration against the dextrose concentration and the patient's total body weight. The foundational formula computes the milligrams of glucose delivered per kilogram per minute (mg/kg/min): GIR = (Infusion Rate in mL/hr * Dextrose Concentration percentage * 1000 mg/g) / (Weight in kg * 60 minutes * 100). When multiple dextrose infusions run concurrently, the individual GIR values are summed together to determine the total glucose load delivered to the patient.

Consider a newborn infant weighing 2.5 kg receiving a peripheral intravenous fluid infusion of 10% Dextrose (D10W) at a rate of 8 mL/hr. To find the GIR, we substitute these values into the formula: GIR = (8 mL/hr * 10% * 1000) / (2.5 kg * 60 min * 100). First, calculate the numerator: 8 * 10 * 1000 = 80,000. Next, calculate the denominator: 2.5 * 60 * 100 = 15,000. Dividing 80,000 by 15,000 yields a Glucose Infusion Rate of 5.33 mg/kg/min, which falls within standard physiological starting ranges for neonates.

Always double-check patient weight measurements, as even minor discrepancies in neonatal weights can drastically alter the calculated GIR. Ensure that dextrose concentrations are entered as percentages (e.g., enter 10 for D10W, not 0.10). Finally, monitor blood glucose levels frequently when adjusting parenteral nutrition parameters to avoid sudden metabolic shifts.