A very good way of predicting how an individual responds to our anaesthetic was the state of their brain network activity at the start of the procedure.
- Srivas Chennu
Currently, patients due to undergo surgery are given a dose of anaesthetic based on the so-called ‘Marsh model’, which uses factors such as an individual’s body weight to predict the amount of drug needed. As patients ‘go under’, their levels of awareness are monitored in a relatively crude way. If they are still deemed awake, they are simply given more anaesthetic. However, general anaesthetics can carry risks, particularly if an individual has an underlying health condition such as a heart disorder.
As areas of the brain communicate with each other, they give off tell-tale signals that can give an indication of how conscious an individual is. These ‘networks’ of brain activity can be measured using an EEG (electroencephalogram), which measures electric signals as brain cells talk to each other. Cambridge researchers have previously shown that these network signatures can even be seen in some people in a vegetative state and may help doctors identify patients who are aware despite being unable to communicate. These findings build upon advances in the science of networks to tackle the challenge of understanding and measuring human consciousness.
In a study published in the open access journal PLOS Computational Biology, funded by the Wellcome Trust, the researchers studied how these signals changed in healthy volunteers as they received an infusion of propofol, a commonly used anaesthetic.
Image: Brain networks during the transition to unconsciousness during propofol sedation
Credit: Srivas Chennu
- Srivas Chennu will be speaking at the Cambridge Science Festival on Wednesday 16 March. During the event, ‘Brain, body and mind: new directions in the neuroscience and philosophy of consciousness’, he will be examining what it means to be conscious.
Reproduced courtesy of the University of Cambridge
______________________________________________________________