What is the NPO deficit for a patient who weighs 50 kg
who has been NPO for 10 hours prior to surgery? The
answer is 1 liter (500 mL 1st hour, 250 mL 2nd hour, and
250 mL 3rd hour). See how the numbers were used on
the calculator below.
Formula
IV fluid replacement for NPO deficit
= 2mL/kg for each hour NPO prior to surgery.
50% of this deficit is replaced 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.
In the example above:
2 mL/kg/hr = 2 x 50 x 10 = 1000
@1st hr, 500 mL will be replaced
2nd hr, 250 mL will be replaced
3rd hr, 2hr 250 mL will be replaced
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.
