|The aim of the BRACCIA project is to reduce
the incidence of awareness during anaesthesia. This rare but distressing
occurence is hard to prevent because there is no 100% reliable measure
of depth of anaesthesia.
| BRACCIA stands for Brain, Respiration And Cardiac
In Anaesthesia. Unlike current depth-of-anaesthesia monitors, which quantify
either brain or cardiovascular activity, BRACCIA is evaluating the dynamics
of both systems. In this
we are investigating
their interactions using modern nonlinear and stochastic techniques.
|BRACCIA exploits the model of the cardiovascular and
brain systems as a set of coupled oscillators. The best known periodic
cardiovascular processes are the cardiac and
cycles. They are mutually coupled, and also coupled to other physiological
oscillations, including brain waves. Determination of the strength and
direction of the coupling between any two
of these oscillators can be highly illuminating, because they define the
overall state of the subject.
|In particular, both the direction and degree of coupling
between the cardiac and respiratory oscillators are known to change when
is in an anaesthetized state, as already demonstrated by the synchronization
of the cardiac and respiratory cycles during anaesthesia.
|By building on earlier results BRACCIA is constructing
a model of the human cardiovascular system and the brain. It can be dynamically
from physiological data, as the subject's depth of anaesthesia varies over
time. Our vision is a new kind of depth-of-anaesthesia
monitor, to help the hospital anaesthetist assess a surgical patient's
level of awareness.
|BRACCIA is an interdisciplinary project involving anaesthetists, physiologists, neuroscientists, biomedical and electrical engineers, information theorists and physicists.