1. Formulas commonly used in the Pediatric/Neonatal Population
By Fiona Campbell BS, RRT-NPS

2. Total Cycle Time (TCT) and Rate
Purpose: To determine a given rate with a given Ti
Order “Rate 30, PIP 26, PEEP 4, Ti 0.3, FiO2 32%”
Many neonatal ventilators will not have a “rate” and must be determined
First find TCT: where TCT=60 (sec/min)÷ desired rate
TCT = 60/30 = 2 sec, by subtracting the Ti, what remains is Te.
Te = TCT – Ti = = 1.7 sec

3. Mean Airway Pressure (Paw)
Average pressure above baseline pressure, determinate of oxygenation
Paw = (PIP – PEEP) x Ti + PEEP
Ti + Te or TCT

4. Mean Airway Pressure (MAP) X FiO2
Oxygen Index (OI)
Determines the mortality of the infant; a more sensitive indicator of severity of pulmonary illness
An OI of 25 indicates HFOV and/or iNO, an OI of > 40 is an indication for ECMO.
OI =
Mean Airway Pressure (MAP) X FiO2
X 100
PaO2