Brain waves could help predict anaesthetic response
Those who had greater brain activity required more anaesthetic to keep them under than those with less activity.
Brain waves are helping scientists at the University of Cambridge predict how individuals respond to general anaesthetic.
A study, published in the journal PLOS Computational Biology, shows how brain signals changed in healthy volunteers as they received an infusion of propofol - a commonly used anaesthetic.
The researchers found that those who had greater brain activity required more anaesthetic to keep them under than those with less activity.
The finding could help doctors predict the amount of anaesthetic individuals need to receive to become unconscious without increasing their risk of complications.
At present, patients who undergo surgery are given a dose of anaesthetic based in the 'Marsh Model'. This 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. 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.
In the study, individuals were asked to carry out a short task while they were administered with a steadily increasing does of propofol. At the same time, scientists measured the brain waves of these patients using an EEG (electroencephalogram).
By the time the patients had reached the maximum dose, some individuals were still awake and able to carry out the task, while others were unconscious. As the researchers analysed the EEG reading, they observed a clear difference between those who responded to the anaesthetic and those who remained able to carry out the task.
Dr Srivas Chennu from the Department of Clinical Neurosciences, University of Cambridge explains: “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. The greater the network activity at the start, the more anaesthetic they are likely to need to put them under.”
Dr Tristan Bekinschtein, senior author from the Department of Psychology, adds: “EEG machines are commonplace in hospitals and relatively inexpensive. With some engineering and further testing, we expect they could be adapted to help doctors optimise the amount of drug an individual needs to receive to become unconscious without increasing their risk of complications."
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