G
Bejjani #, O. Caelen*, G. Bontempi*, L. Perrin #, L. Barvais#, * Machine
Learning Group, Computer Science, Université Libre de Bruxelles, Belgium; #
Erasmus Hospital Anaesthesia Departments, Université Libre de Bruxelles,
Belgium
Introduction:
Target
Controlled Infusion (TCI) of Propofol and Remifentanil using the population
Pharmacokinetic sets of Schnider and Minto, respectively becomes more and more a
popular anaesthesia technique due to the commercialisation of the BasePrimeA of
Fresenius and the Alaris Pharmacokinetic pumps. The BIS (Aspect USA) and the Entropy module of GE (Maddison
USA) are EEG monitoring which are useful to titrate the hypnotic and analgesic
components (ref). Even if EEG
monitoring is routinely used, the opioid administration is often still based
during the clinical practice on the individual sympathetic patient’s answer to
the intensity of the noxious stimulus. The
aim of the study was to compare retrospectively if the use of predefined
algorithms of the effect site concentration (Ce) of
propofol titration according to the patient’s EEG answer combined with
the use of predefined algorithms of remifentanil Ce titration based on a range
of heart rate and systolic blood pressure values could help the anesthetist.
Material
and Methods:
Eighteen
patients were anaesthetised using the TOOLBOX System with the automated propofol
and remifentanil TCI titration according to a predefined range of BIS and
hemodynamic values. The TCI
induction phase was manually titrated by the anaesthesiologist in charge of the
patient and the semi-automated control was started after the tracheal intubation
phase until the end of surgery. During
the surgery, the anaesthesiologist could adapt the BIS and haemodynamic range.
Moreover, at any time, the anaesthesiologist could adapt the proposal of
the semi-automated pilot and he was always the final decider.
All the haemodynamic data and the Ce target concentrations were saved
every 5 seconds. A group of 23
patients undergoing the same type of digestive surgery lasting more than 2 hours
but anaesthetised by the same TCI TOOLBOX system with a manual control of the
most appropriate remifentanil and propofol Ce was used as a control group
Results:
|
|
Semi-Automated
Control |
Manual
Control |
|
Mean
Propofol Ce |
2.4±0.9 |
2.7
±0.8 |
|
N
= Ce Propofol
adaptations/hour |
30.9 |
2.3 |
|
Mean
Remifentanil Ce |
5.2±2.4 |
6.1
±2.4 |
|
N
= Ce Remifentanil adaptations/hour |
18.5 |
4.4 |
|
%
Time BIS in the 40-60 Range |
64.5 |
50.8 |
|
%
Time BIS less than 40 |
27.9 |
43.4 |
|
%
Time BIS more than 70 |
3.6 |
7.5 |
Discussion:
The
number of actions of an automatic controller is much higher than the
anaesthesiologist TCI responsiveness. The
use of such a system decreases the number of episodes of BIS values out of the
proposed Range 40-60. The
semi-automated system allows also decreasing the likelihood of BIS values
greater than 70 which could be associated with awareness. In conclusion the use
of a semi-automated pilot to help the effect site TCI titration of propofol and
remifentanil seems interesting to be tested in the future in a prospective and
randomised study
References: