Correction of target-controlled infusion following wrong selection of emulsion concentrations of propofol

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 (C(eff)) of propofol, and the emulsion concentrations were selected for 2.0% instead of 1.0% (FALSE(1-2), n = 24), or 1.0% instead of 2.0% (FALSE(2-1), 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 FALSE(2-1), the overdose was evacuated while targeting C(eff) (n = 12) or targeting plasma concentration (C(p)) (n = 12). The gravimetrical measurements of TCI reproduced the C(p) and C(eff) using simulations. The reproduced C(eff) at 3 min (C(eff-3min)) and the time to be normalized within ± 5% of target C(eff) (T(±5%)), were compared between the correction methods. RESULTS: During the wrong TCI, C(eff-3min) was 1.98 ± 0.01 µg/ml in FALSE(1-2), and 7.99 ± 0.05 µg/ml in FALSE(2-1). In FALSE(1-2), 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 FALSE(2-1), T(±5%) was significantly shorter during targeting C(p) (3.6 ± 0.04 min) than targeting C(eff) (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.