Comparison of the Cortínez and the Schnider models with a targeted effect-site TCI of 3 mcg/ml in biophase in healthy volunteers.
OBJECTIVE
To compare the Cortínez and Schnider models in effect-site TCI mode (3 mcg/ml) in healthy volunteers.


METHODS
Ten healthy volunteers were prospectively studied on 2 occasions. Propofol was administered with the Cortínez or the Schnider models, as randomly assigned. Times and predicted concentrations at the time of loss and recovery of consciousness (LOC and ROC), mass of drug administered, BIS, and haemodynamic variables were compared. Statistical analysis was with paired Wilcoxon test. A P<.05 was considered significant.


RESULTS
The propofol bolo was higher (1.4 [1.3-1.6] versus 0.9 [0.7-1.3] mg/kg, P=.005) and the LOC occurred earlier (1.33 [0.67-6.83] versus 3.87 [1.66-11.08] minutes, P=.02) with the Cortínez model compared to the Schnider model. With the Cortínez model, LOC occurred at an effect site concentrations of 2.6 (1.65-3.0) mcg/ml. With the Schnider model, LOC occurred at 3.87 min (1.66-11.8) after reaching the target of 3 mcg/ml. (P=.001). BIS values, infusion rates, and haemodynamic variables were similar between models after 20minutes of infusion (P>.5). Recovery (ROC) was longer with the Cortínez model (11.6 [8.1-16.2] vs. 8.5 [4.7-15.5] min, P=.003).


CONCLUSIONS
The Cortínez model is a good alternative to the Schnider model for use in effect-site TCI mode in normal weight subjects. With the target used in this study (3 mcg/ml), the slower Ke0 incorporated into the Cortínez model better discriminated the LOC time.
Departamento de Anestesiología, Clínica Santiago de León, Caracas, Venezuela. Electronic address: carolinafrederico@gmail.com.
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Frederico Avendaño
Departamento de Anestesiología, Escuela de Medicina, Pontificia Universidad Católica de Chile, Santiago, Chile.
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Cortínez
Departamento de Anestesiología Clínica Ávila, Caracas, Venezuela.
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Ramírez-Paesano
D018686:Anesthetics, Intravenous / Q000627:therapeutic use*; D003243:Consciousness; D064368:Healthy Volunteers; D006801:Humans; D007262:Infusions, Intravenous; D008962:Models, Theoretical; D015742:Propofol / Q000627:therapeutic use*
D018686:Anesthetics, Intravenous; D015742:Propofol
Farmacocinética; Ke0; Perfusión controlada por objetivo; Pharmacokinetics; Propofol; Target controlled infusion