Anaesthesia
-
Randomized Controlled Trial Multicenter Study Comparative Study Clinical Trial
TCI compared with manually controlled infusion of propofol: a multicentre study.
This prospective, randomised multicentre study was designed to determine the clinical profile of 'Diprifusor' target controlled infusion compared with manually controlled infusion of propofol in 562 patients, aged 18-85 years, in a range of surgical procedures in 29 centres. The dose of propofol required for loss of consciousness was statistically significantly lower in the target controlled infusion group [1.69 (0.50) vs. 2.31 (0.75) mg.kg-1, p < 0.001] but the overall rate of propofol administration was slightly, but significantly, higher [12.1 (5.1) vs. 11.0 (6.0) mg.kg-1.h-1, p < 0.05]. The target concentration (CT) required for induction decreased with increasing age and ASA class, with premedication and with the administration of an opioid before induction. ⋯ Despite the lack of experience of most investigators in using target controlled infusion, the clinical profiles of both propofol administrations were similar. Data suggest that the clinical profile of target controlled infusion may be improved with experience, for example by more active titration of CT to effect. Target controlled infusion may well become the preferred choice for anaesthetists.
-
Total intravenous anaesthesia may be most beneficial for day-case surgery with regard to quality of recovery, lack of complications and the ability to sustain an efficient throughput of patients. However, the technique can be applied to all forms of surgery and, with a little practice, consistent results will be achieved. ⋯ The commercially available 'Diprifusor', a target controlled infusion system for propofol, can facilitate the more widespread use of total intravenous techniques and allow their potential benefits to be applied and appreciated more widely. This review outlines some practical considerations that should enable a more confident approach to total intravenous techniques by anaesthetists who are unfamiliar with them.
-
The development of new short-acting anaesthetic drugs, improved drug assay techniques and the availability of reliable infusion systems opened the field of clinical pharmacokinetics and pharmacodynamics. The tri-exponential drug concentration decay complicates the definition of therapeutic dosage regiments and prevents straightforward prediction of recovery from drug effects. The context-sensitive half-time, the time required for drug blood concentration to decrease to half its value, provides a useful comparative predictor of drug concentration decline after infusion. ⋯ The rationale for drug infusion is reduction of fluctuating drug concentrations and drug effects. A variability similar to that observed with the use of inhalation agents, must be achieved by the choice of an appropriate pharmacokinetic model. The use of a target controlled infusion device, delivering proportional changes based on pharmacokinetic principles, allows titration of the concentration against clinical effect in individual patients.
-
Review Comparative Study
Intravenous anaesthesia: manual infusion schemes versus TCI systems.
Propofol was first used to induce and maintain anaesthesia in the early 1980s. Several infusion regimens were described, some based on pharmacokinetic predictions. Advances in computing technology subsequently have allowed the development of portable target controlled infusion devices, with drugs delivered to achieve specific predicted target blood propofol concentrations. Assessments of propofol target controlled infusion systems in clinical practice and comparisons of 'Diprifusor' target controlled infusion systems with manual infusion are reviewed here.