TCI: Target Controlled Infusion, or Totally Confused Infusion? Call for an Optimised Population Based Pharmacokinetic Model for Propofol.
2008 (English)In: Upsala Journal of Medical Sciences, ISSN 0300-9734, E-ISSN 2000-1967, Vol. 113, no 2, 161-169 p.Article in journal (Refereed) Published
Different pharmacokinetic models for target controlled infusion (TCI) of propofol are available in the recently launched open TCI systems. There is also a compelling choice to work with either plasma-or effect-site targets. Knowledge about the clinical consequences of different alternatives is of importance. We aimed to illustrate the potential differences in the actual drug delivery/output between three present commercially available and clinically used pharmacokinetic models: the original Marsh model, which is also implemented in the Diprifusor (R), the "modified Marsh-" and the Schnider models. Simulations were made in the TivaTrainer program (eurosiva.com). Firstly, our standard plasma target regimen was simulated, and secondly an effect-site target of 3.5 mu g/mL was chosen. Thirdly, real infusors were used for measuring the time to reach defined predicted effect-site concentrations when aiming at a plasma target of 6 mu g/mL. Identical patient characteristics were used in all simulations: male, 170 cm, 70 kg, 40 years of age. Resulting predicted effect- site peak concentrations, and used bolus doses were recorded, as were the resulting plasma over-shoot, and time frames. The plasma target regimen gave predicted effect- site peaks in the different models ranging from 3.6 to 7.2 mu g/mL, reached after 2(3)/(4) to 4 minutes. To reach the same effect- site target, the three models used bolus doses ranging from 68 to 150 mg given during 22 to 46 seconds. The predicted plasma concentration over-shoots varied from 5.0 to 13.4 mu g/mL. There were obvious differences between the models in the time taken to reach defined effect- site concentrations. We observed clinically significant different results between the models. The choice of model will make a difference for the patient. To eliminate confusion-not necessarily to improve precision-we call for an optimised population based pharmacokinetic model for propofol-a consensus model!
Place, publisher, year, edition, pages
2008. Vol. 113, no 2, 161-169 p.
Medical and Health Sciences
IdentifiersURN: urn:nbn:se:uu:diva-149287ISI: 000263415200004PubMedID: 18509810OAI: oai:DiVA.org:uu-149287DiVA: diva2:404534