Formula: IV fluid replacement for NPO deficit
2 mL × W × H
- W = Weight in kilograms (kg)
- H = Hours
IV fluid replacement for NPO deficit = 2 milliliter/kilogram (2mL/kg) for each hour NPO prior to surgery. Replace 50% of deficit within the first hour of surgery with the remaining 50% being replaced over the next 2 hours. If the patient stayed in the hospital overnight with an IV infusing while NPO, subtract this amount from the NPO deficit.
Replace the NPO deficit for a patient who weighs 50 kg who has been NPO for 10 hours prior to surgery?
- NPO deficit = 2mL × 50 kg × 10 Hrs
- NPO deficit = 1,000 mL
- ½ NPO deficit = 500 mL
Answer: Give 500 mL the first hour then 250 mL the second hour and another 250 mL the 3rd hour. If in this example, the patient stayed in the hospital overnight with an IV infusion at 100 mL/hr while NPO, all their NPO deficit (1 liter) would already be replaced.