Four steps to confident target-controlled infusion. Progress is saved on this device.
Before you start: how confident are you programming and interpreting a TCI pump?
Each model describes propofol moving between a central compartment (V1), a fast peripheral (V2) and a slow peripheral (V3), cleared by Cl1–Cl3.
The effect site is a tiny virtual compartment linked by ke0. Its concentration (Ce) lags plasma (Cp) and drives the clinical effect.
Marsh scales everything to the weight you enter. Schnider fixes V1 and uses age, height and James LBM. Eleveld uses fat-free mass, age, sex and opioid status across the lifespan.
A model is only as good as the population it was built on. Outside that range, predictions are extrapolation.
In Cp mode the pump holds plasma at target; the brain catches up later.
In Ce mode the pump overshoots plasma to bring the effect site to target faster. The size of that overshoot depends on ke0.
The same Ce can mean different depths. Older brains are more sensitive (lower Ce50) and opioids add effect.
Use the frontal EEG and spectrogram to check what the model cannot see: alpha–delta patterns, burst suppression, or arousal.