Research has revealed elderly patients who get delirium after having surgery can triple their chances of developing dementia.
The disturbed mental state which causes confusion and disorganised thinking affects more than half of people who undergo surgery and are over 65.
Professor Hugh Hemmings from the British Journal of Anaesthesia where the research is published explains the affects.
"It's an acute confusional state that accompanies the associated with toxins, drugs but also the stress and impact of surgery and anesthesia," he said.