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ID
Source
Brief title
Health condition
elective surgery under general anaesthesia with propofol and requiring an arterial line for invasive blood pressure monitoring as part of their clinical care
Target-Controlled Infusion,propofol,pk/pd
Sponsors and support
Intervention
Outcome measures
Primary outcome
We hypothesize that online adaptation or individualization of the population PKPD model of propofol will decrease the residual error between predicted and measured plasma-concentrations during maintenance of anaesthesia, when the adapted PKPD models are used to calculate propofol infusion rates required for the plasma concentrations set by the responsible anaesthetist
Secondary outcome
Secondly, we will compare the hypnotic and haemodynamic stability before and after the adaptation as measured by EEG and other vital signs clinical monitoring
Background summary
Population based pharmacokinetic-dynamic (PKPD) models of propofol are used in daily practice to titrate propofol towards a predicted plasmaand/
or effect-site concentration. 1-4 It has been accepted that the population based prediction of the propofol plasma concentration may have
an error of about 20% compared to the measured propofol concentrations in the individual patient. 5 This error is considered acceptable in the
clinically applied new generation target controlled infusion (TCI) systems for propofol administration 6-8.
Recently, new technology has been developed to measure propofol concentrations in plasma with minimal delay of about 10 minutes after
sampling. This technology opens opportunities to decrease the residual error between predicted (population) and measured (individual)
propofol plasma concentrations during maintenance of anaesthesia. A decrease of the prediction error has several potential advantages such
as less accumulation of drug, faster recovery from anaesthesia, less overshoot in propofol effect when adjusting the dose etc…
Our study tests whether online adaptation of the population PKPD model (being used to calculate the infusion rates during maintenance of
anaesthesia), based on differences measured and predicted concentrations, will decrease the residual errors between subsequent
measurements and predicted concentrations. Such an individualization of the population PKPD should be done in a Bayesian approach as it
has been shown to be a good method of updating pharmacokinetic models during infusion, when intermittent drug concentration measurements
are performed 9. This method adapts the starting (population) pharmacokinetic model, on the basis of the measured blood samples to generate
a patient-individualized model.
Study objective
We hypothesize that adaptation or tuning of the population PKPD model of propofol will decrease the residual error between predicted and measured plasma-concentrations during maintenance of anaesthesia. The adapted PKPD models can also be used online to calculate propofol infusion rates required for the target concentrations set by the responsible anaesthetist. Doses given to the patients remain within the control of the attending anaesthetist at all times and within clinically accepted dosing guidelines. We only test whether the error between prediction and measurement decreases when an individualized PKPD model is used to predict required propofol infusion rates compared to a non-adaptive population typical value PKPD model.
Study design
1 day = the day of the operation
Intervention
Patients receive propofol by means of a PKPD model. Initially a classical population based PKPD model is used. Based on results from intra-operative sampling an individualized PKPD model is used. Anesthesiologists will know when changes in regimen can occur. However, due to blinding, they will not know whether the patient is enrolled in the control group (nothing changes) or in the intervention group (regimen is individualized).
Inclusion criteria
-Age between : 18 years and 75 years
-Informed patient consent
-ASA Class (American Society of Anesthesiologists physical status) I- III
- Scheduled for elective surgery under general anaesthesia with propofol and requiring an arterial line for invasive blood pressure monitoring as part of their clinical care will be enrolled.
Exclusion criteria
•patient refusal
•CNS diseases (dementia, CVI, seizures, psychiatric diseases)
•Regular intake of CNS active drugs (benzodiazepines, antidepressants,
antipsychotics, anticonvulsants)
•Regular intake of opioids (morphine > 30 mg/day)
•Relevant hepatic disease (Child B or higher)
•Body mass index (BMI) <18 or >35 kg/m2
•Pregnancy, or currently nursing
•Overt signs of alcohol abuse
•Contraindications or allergies to the drugs used in the study
•Expected blood loss during surgery > 2000 ml
Design
Recruitment
Followed up by the following (possibly more current) registration
No registrations found.
Other (possibly less up-to-date) registrations in this register
No registrations found.
In other registers
| Register | ID |
|---|---|
| NTR-new | NL4387 |
| NTR-old | NTR4518 |
| Other | : METc 2013/374 |