Some anaesthetics used during surgery could increase the risk of Alzheimer's disease and dementia in elderly patients, according to new research carried out by scientists in the US.
Pravat Mandal from the University of Pittsburgh Medical School in Pennsylvania says that some general anaesthetics could reduce the rate at which cells develop in the brain.
Recent test tube and animal experiments have also revealed that certain anaesthetics can encourage the clumping together of beta amyloid proteins, which can kill brain cells and hasten the onset of Alzheimer's and other memory related conditions.
Mr Mandal revealed that the inhaled anaesthetics halothane and isoflurane are particularly problematic in this respect, as is the intravenous anaesthetic propofol when used in higher concentrations.
The research, as reported by New Scientist magazine, suggests that elderly people are more at risk because they have more beta amyloid in their brains and they are more likely to go through lengthy operations such as hip replacements and heart bypass surgery.
Mr Mandal said he hopes the findings will lead to an urgent investigation into the dangers and benefits of individual anaesthetics. "The main focus should now be using an anaesthetic that does not have any undesirable and deadly effects," he said.