Background: We investigated the correction methods following wrong-settings of emulsion
concentrations of propofol as a countermeasure against erroneous target-controlled infusions
(TCI).
Methods: TCIs were started with targeting 4.0 μg/ml of effect-site concentration (Ceff) of
propofol, and the emulsion concentrations were selected for 2.0% instead of 1.0% (FALSE1-
2, n = 24), or 1.0% instead of 2.0% (FALSE2-1, n = 24). These wrong TCIs were corrected at
3 min after infusion start. During FALSE1-2, the deficit was filled up while injecting after
equilibrium (n = 12), or while overriding (n = 12). During FALSE2-1, the overdose was
evacuated while targeting Ceff (n = 12) or targeting plasma concentration (Cp) (n = 12). The
gravimetrical measurements of TCI reproduced the Cp and Ceff using simulations. The
reproduced Ceff at 3 min (Ceff-3min) and the time to be normalized within ± 5% of target Ceff
(T±5%), were compared between the correction methods.
Results: During the wrong TCI, Ceff-3min was 1.98 ± 0.01 μg/ml in FALSE1-2, and 7.99 ± 0.05
μg/ml in FALSE2-1. In FALSE1-2, T±5% was significantly shorter when corrected while
overriding (3.9 ± 0.25 min), than corrected after equilibrium (6.9 ± 0.05 min) (P < 0.001). In
FALSE2-1, T±5% was significantly shorter during targeting Cp (3.6 ± 0.04 min) than targeting
Ceff (6.7 ± 0.15 min) (P < 0.001).
Conclusions: The correction methods, based on the pharmacokinetic and pharmacodynamic
characteristics, could effectively and rapidly normalize the wrong TCI following erroneously
selections of the emulsion concentration of propofol.
