Definitions and criteria for postoperative cognitive dysfunction

Monday 5 June, 08h30-10h00, Room 3

Cognitive disorders are the focus of this 3-part session on the final day of Euroanaesthesia. In the first presentation, Associate Professor Lis Evered (St. Vincent’s Hospital, Melbourne; and Anaesthesia, Perioperative and Pain Medicine Unit, University of Melbourne, Australia) will discuss the nomenclature of these disorders.

“Cognitive change affecting elderly patients after anaesthesia and surgery has been recognised for over 100 years,” says Prof Evered. “Multiple publications have demonstrated cognitive change following cardiac and non-cardiac surgery 7 days and 3 months after surgery. There is evidence supporting cognitive changes, including increased prevalence of dementia, up to 7.5 years later.”

Research into these cognitive changes in the perioperative period has been undertaken in isolation from cognitive studies in the community making clinical relevance and interpretation of these changes difficult. In her talk, Prof Evered aims to encourage people to use language and diagnostic criteria which are consistent with the terminology used in the wider clinical community.

In order to align cognitive change associated with anaesthesia and surgery with cognitive change in other medical disciplines providing meaningful clinical interpretation, Prof Evered will use the Diagnostic and Statistical Manual for Mental Disorders 5th Edition (DSM-5), and the National Institute on Aging–Alzheimer’s Association guidelines (NIA-AA).

She says: “Furthermore, postoperative delirium should be specifically labelled as such to recognise it as a significant clinical event. This presentation will provide the history and background to this problem, detail the specific nomenclature proposed and how this aligns with that of other medical disciplines, provide examples of outcomes with clinical data and a summary of the impact on clinical practice and research and ultimately improved healthcare for the elderly.”

The second presentation, “postoperative delirium in the elderly: we need to improve perioperative care”, will be given by Professor Mark Coburn, Department of Anesthesiology, University Hospital RWTH Aachen, Germany.

Population demographics predict a dramatic growth in the number of elderly patients undergoing an increasing variety of surgical procedures. Yet the aetiology of postoperative delirium is complex, poorly understood, and multifactorial [1].

“The risk of postoperative delirium increases with age, pre-existing cognitive impairment, dementia, depression, comorbidity and vascular disease,” says Prof Coburn. “Delirium is a costly complication of medical and perioperative care in terms of subjective experience, financial implications, mortality, and long-term outcomes. Understanding of the predisposing risk factors, however, is still in its infancy. Especially in the elderly the occurrence of postoperative delirium has been identified as a risk factor for increased mortality and for posttraumatic stress disorder [2, 3].”

The recently published ESA evidence-based and consensus-based guideline on postoperative delirium provides the best available evidence.  This includes evaluating preoperative risk factors for postoperative delirium in the elderly surgical patient (cognitive impairment, functional status, malnutrition and sensory impairment). Furthermore, key elements regarding prevention and treatment of postoperative delirium are non-pharmacological measures such as orientation-, visual- and hearing aids, maintenance of a day/night rhythm, early mobilisation and early nutrition [4].

Prof Coburn concludes; “Although we may have improved but we must get better still in the perioperative management of all consecutive stages of preoperative, intraoperative and postoperative care to reduce the incidence, duration and severity of postoperative delirium in the elderly.”

Prof Evered then returns to discuss ‘long-term perioperative cognitive disorders’.  She says: “Many elderly patients suffer delirium and postoperative cognitive decline in the short and medium term. There is also evidence that cognitive function may be affected as far as 7.5 years following cardiac surgery.”

Delirium is known to increase the risk of subsequent dementia, but it is not known if short and medium term cognitive decline postoperatively impact long-term decline. It is known that subtle baseline impairment is common and is associated with postoperative cognitive decline, but the identification of true preoperative cognitive trajectories has been overlooked.

She will explain that frailty is associated with medium term cognitive decline, but may be a modifiable factor in some patients demonstrating improvement over 12 months. Cognitive decline in the elderly ultimately leads to a decline in function and independence, and associated healthcare and social costs. Postoperative cognitive decline is associated with preoperative vulnerabilities including baseline cognitive impairment, increasing age and poor education.

She concludes: “Much work is currently investigating the role of inflammation and methods to modify any effects. Animal models demonstrate an association between anaesthetic agents and Alzheimer’s disease (AD) pathology.  Preoperative cognitive assessment is essential to identify at-risk individuals, and offer the opportunity to intervene and prevent decline and poor postoperative outcomes.”


  1. Inouye SK, Westendorp RG, Saczynski JS. Delirium in elderly people. Lancet 2014; 383: 911-22
  2. Kavouspour C, Wang N, Mears SC, et al. Surgical procedure and postoperative delirium in geriatric hip fracture patients. Eur J Anaesthesiol 2016; 33:230–231.
  3. Sanders RD, Pandharipande PP, Davidson AJ, et al. Anticipating and managing postoperative delirium and cognitive decline in adults. BMJ 2011; 343:d4
  4. Aldecoa C et al. European Society of Anaesthesiology evidence-based and consensus-based guideline on postoperative delirium. Eur J Anaesthesiol 2017; 34: 192-214

For the ESA Guidelines on postoperative delirium, see: