Warmth, glucose and fluid are one physiological system: a cold newborn burns glucose and oxygen to make heat. Every number on this bench is per kilogram, per hour or per week of gestation, and every calculation is written out, because in this population a decimal point is a diagnosis. Five benches: the hour-specific glucose thresholds, the glucose infusion rate, maintenance fluid, the weight-based dose against the adult ceiling, and the feeds that precede necrotising enterocolitis.
Choose the calculation
Why is this newborn being screened at all? Screening is targeted, not universal.
Glucose infusion rate in mg/kg/min equals the dextrose percentage multiplied by the rate in mL/hr, divided by the weight in kilograms multiplied by 6. Start an infusion at 5 to 8 mg/kg/min.
The 4–2–1 rule gives an hourly maintenance volume. The Holliday-Segar 100/50/20 mL/kg/day rule gives the same answer expressed per day. Neither applies to the first days of life.
Then perform the step that is skipped most often: compare the calculated dose against the maximum adult dose. A formula that is correct for a 12 kg toddler becomes an overdose in a 70 kg adolescent.
Which of these have you found? The early signs of necrotising enterocolitis are quiet.