The influence of target concentration, equilibration rate constant (k_e0) and pharmacokinetic model on the initial propofol dose delivered in effect-site target-controlled infusion

Abstract

SummaryOne advantage of effect-site target-controlled infusion is the administration of a larger initial dose of propofol to speed up the induction of anaesthesia. This dose is determined by the combination of the pharmacokinetic model parameters, the target setting and the blood-effect time-constant, k e0 . With the help of computer simulation, we determined the k e0 values required to deliver a range of initial doses with three pharmacokinetic models for propofol. With an effect site target of 4 lg.ml , respectively. These k e0 values have the attractive feature that, when used to simulate the administration schemes used in two previous studies, predicted effect site concentrations at loss of consciousness were close to those required for maintenance of anaesthesia.

Comparison of the Effects of Dexmedetomidine on the Induction of Anaesthesia Using Marsh and Schnider Pharmacokinetic Models of Propofol Target-Controlled Infusion

“…To the best of our knowledge, there have been no studies of the effects of dexmedetomidine on different TCI pharmacokinetic models. In the present study, the loading dose of dexmedetomidine resulted in a lower target concentration requirement for successful induction and a shorter induction All numerical data were expressed in mean (SD); all categorical data were expressed in n (%) , respectively (10). Thus, in terms of the Cet, the Schnider model had a faster ke0, even without the dexmedetomidine effect (10).…”

Management of hypotension with vasopressors at caesarean section under spinal anaesthesia – have we found the Holy Grail of obstetric anaesthesia?

“…There is no drug licence for these other models and, therefore, no separate prescribing information. Clearances of the models are largely similar but, for this study, other components of the pharmacokinetic model are extremely important such as the ke0 [10][11][12][13]. As Sep ulveda V et al indicate, their results could be explained by a selection of a too large (or fast) ke0.…”

“…© 2017 The Association of Anaesthetists of Great Britain and Ireland Anaesthesia 2018, 73,[3][4][5][6][7][8][9][10][11][12][13][14] Editorial…”

Model-based drug administration

“…However, Seo and coworkers [12] studied various extended Marsh models using various k e0 values and found different effect-site concentrations at loss and return of consciousness, dependent on the applied model. Glen and Engbers [13] used a more pragmatic approach to KEY POINTS TCI is a mature technology used in many countries nowadays.…”