Cognitive dysfunction after surgery and anaesthesia: what can we tell the grandparents?

'Grandpa was never the same after his operation!'. This statement describes a myriad of possible clinical difficulties that can afflict older people after hospitalisation for major surgery. We summarise the evidence pertaining to the phenomenon of Postoperative Cognitive Dysfunction, a condition defined as an abnormality on neuropsychological testing, which is said to afflict up to 14% of over 70 years olds undergoing elective surgery. So far none of the expected surgical, anaesthetic and environmental risk factors have been convincingly demonstrated to be responsible for this observed deterioration. While recognising the high incidence of the condition as an neuropsychological entity we accept that it is difficult to translate this into a reliable estimate of clinical risk for the individual patient.