Study of the time course of the clinical effect of propofol compared with the time course of the predicted effect-site concentration: Performance of three pharmacokinetic-dynamic models.
Br J Anaesth
; 104(4): 452-8, 2010 Apr.
Article
em En
| MEDLINE
| ID: mdl-20190259
ABSTRACT
BACKGROUND:
In the ideal pharmacokinetic-dynamic (PK-PD) model for calculating the predicted effect-site concentration of propofol (Ce(PROP)), for any Ce(PROP), the corresponding hypnotic effect should be constant. We compared three PK-PD models (Marsh PK with Shüttler PD, Schnider PK with fixed ke0, and Schnider PK with Minto PD) in their ability to maintain a constant bispectral index (BIS), while using the respective effect-site-controlled target-controlled infusion (TCI) algorithms.METHODS:
We randomized 60 patients to Group M (Marsh's model with k(e0)=0.26 min(-1)), Group S1 or Group S2 (Schnider's model with a fixed k(e0)=0.456 min(-1) or a k(e0) adapted to a fixed time-to-peak effect=1.6 min, respectively). All patients received propofol at a constant rate until loss of consciousness. The corresponding Ce(PROP), as calculated by the respective models, was set as a target for effect-site-controlled TCI. We observed BIS for 20 min. We hypothesized that BIS remains constant, if Ce(PROP) remains constant over time.RESULTS:
All patients in Group M woke up, one in Group S1 and none in Group S2. In Groups S1 and S2, BIS remained constant after 11 min of constant Ce(PROP), at a more pronounced level of hypnotic drug effect than intended.CONCLUSIONS:
Targeting Ce(PROP) at which patients lose consciousness with effect-site-controlled TCI does not translate into an immediate constant effect.
Texto completo:
1
Base de dados:
MEDLINE
Assunto principal:
Propofol
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Anestésicos Intravenosos
Tipo de estudo:
Clinical_trials
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Prognostic_studies
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Risk_factors_studies
Limite:
Adult
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Female
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Humans
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Male
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Middle aged
Idioma:
En
Ano de publicação:
2010
Tipo de documento:
Article