Korean J Anesthesiol.  2013 Oct;65(4):299-305. 10.4097/kjae.2013.65.4.299.

The comparison of predictive performance in bispectral index prediction during target effect-site controlled infusion of propofol using different blood effect-site equilibration rate constants in the same pharmacokinetic model

• Choi BM
• Bang JY
• Jung KW
• Lee JH
• Bae HY
• Noh GJ

• KMID: 2164864
• DOI: http://doi.org/10.4097/kjae.2013.65.4.299

Abstract

BACKGROUND
Blood-brain equilibration rate constant (k(e0)) is derived from either pharmacokinetic and pharmacodynamic modeling (k(e0_model)) or a model-independent observed time to peak effect (k(e0_tpeak)). Performance in bispectral index (BIS) prediction was compared between k(e0_model) and k(e0_tpeak) for microemulsion or long chain triglyceride (LCT) propofol.
METHODS
Time to peak effect (t(peak), time to a maximally reduced BIS value) of microemulsion propofol after an intravenous bolus (1 mg/kg) was measured in 100 patients (group A(micro)). An observed t(peak) of 1.6 min for LCT propofol was obtained from an earlier study. Another 40 patients received a target controlled infusions of microemulsion propofol (k(e0_model) = 0.187/min, group B(micro) = 20) or LCT propofol (k(e0_model) = 0.26/min, group B(LCT) = 20) and remifentanil. The k(e0_tpeak)'s in group B(micro) and B(LCT) were calculated using the observed t(peak) value obtained from group A(micro) and 1.6 min, respectively. Effect-site concentrations of propofol were recalculated using the amounts of propofol infused over time and k(e0_tpeak)'s. Predicted BIS values calculated by sigmoid Emax equations with k(e0_model) and k(e0_tpeak) were compared with observed BIS values during induction and emergence for both formulations of propofol.
RESULTS
Observed t(peak) of microemulsion propofol was 1.68 min. The median performance errors of BIS in group B(micro) were -1.83% (-24.8 to 18.9, k(e0_model)) and -2.42% (-26.1 to 36.2, k(e0_tpeak)), while 8.01% (-20.5 to 30.1, k(e0_model)) and 7.37% (-27.0 to 49.1, k(e0_tpeak)) in group B(LCT). The median absolute performance errors of BIS in group B(micro) were 11.87% (2.2-31.1k(e0_model)) and 14.38% (-0.6 to 44.6, k(e0_tpeak)), while 17.31% (5.54-36.0, k(e0_model)) and 18.28% (-0.1 to 56.0, k(e0_tpeak)) in group B(LCT).
CONCLUSIONS
The k(e0_model) showed better performance in BIS prediction than the k(e0_tpeak).

Keyword

Bispectral index; Pharmacokinetic; Propofol

MeSH Terms

Colon, Sigmoid
Humans
Pharmacokinetic*
Piperidines
Propofol*
Piperidines
Propofol