The impact of the peri‐operative period on cognition in older individuals

Abstract

This review aims to highlight the importance of peri-operative and longer-term postoperative cognitive changes and to put them in the context of other cognitive disorders. Cognitive decline is common among the elderly and is impacted by many factors, both known and unknown. Individuals aged 65 years and above comprise the most frequent users of the healthcare system; thus this group is at risk of both cognitive decline associated with ageing, such as mild cognitive impairment and Alzheimer's disease, and cognitive disorders associated with surgery and anaesthesia, including delirium and postoperative cognitive dysfunction. Until now research and management of geriatric cognitive disorders has occurred in isolation from peri-operative medicine and research, such that any overlap between the cognitive disorders has been largely overlooked. Factors contributing to this division include the classification of geriatric cognitive disorders according to Diagnostic and Statistical Manual of Mental Disorders (DSM) and International Classification of Diseases (ICD) criteria, while cognitive disorders associated with the peri-operative period are largely research diagnoses. Given the large overlap between individuals at risk of cognitive decline (those aged 65 or above) and individuals exposed to surgery and anaesthesia, consideration of the role of the peri-operative period in geriatric cognitive disorders is imperative. Recent work investigating postoperative cognitive dysfunction has identified baseline cognitive function as a more significant predictor of further decline than increasing age, suggesting that preoperative cognitive trajectory may be the most important factor in determining postoperative decline. Both animal and human data provide evidence of a role of inflammation in cognitive decline, although this area requires further research to definitively identify associations and possible therapeutic strategies. Given the ageing population and the associated healthcare costs of caring for an increasing number of individuals suffering cognitive decline, any insults that exacerbate this problem need to be avoided. Understanding the overlap between geriatric and postoperative cognitive disorders is essential to ensure appropriate healthcare management of the elderly.

Neuroprotective Effects against POCD by Photobiomodulation: Evidence from Assembly/Disassembly of the Cytoskeleton

“…Cognitive reserve and trajectory are perhaps the most important factors that influence the risk of POCD. 29 Additional factors include length and complexity of the surgery (with cardiac surgery possibly being more risky than noncardiac surgery), 20,28 a history of alcohol abuse, 30 previous stroke, 28 diabetes mellitus, hypertension, atherosclerosis, 31 and postoperative complications, especially respiratory complications and postoperative infections. 27 A recent study has also identified gender as a factor, with females being at greater risk than males, 32 as is the case with AD.…”

Hypertension and Risk of Post-Operative Cognitive Dysfunction (POCD): A Systematic Review and Meta-Analysis

“…Post-operative cognitive dysfunction (POCD) occurs frequently after major surgery [ 1 ]. It is broadly defined as an impairment of a patient’s cognitive functioning relative to their pre-surgery cognitive status [ 2 ].…”

Diabetes, but Not Hypertension and Obesity, Is Associated with Postoperative Cognitive Dysfunction

“…Large individual differences in POCD spanning cognitive recovery during the first few months to persistent cognitive impairment have been reported [1-5]. Although it has been the subject of extensive research during the past two decades, many questions remain unanswered, and a lack of uniform diagnostic criteria [6] and differences in length of follow-up period hamper comparability between studies. Little is currently known about potential risk factors, which help to identify at-risk patients and shed light on underlying pathophysiology.…”