Long-Term Cognitive Decline in the Elderly is not Attributable to Surgery/Anesthesia

Postoperative cognitive dysfunction (POCD) is a topic of special importance for elderly patients. Based upon the results of a combination of retrospective human studies, experiments in animals, and a number of prospective human studies, the anesthesia research community has advanced the notion that surgery/anesthesia might precipitate permanent incident dementia. A careful analysis of the data, however, reveals numerous methodological problems with the clinical trials that have examined long-term POCD, including the vague definition of POCD, poorly matched controls (or lack of controls in some investigations), arbitrary diagnostic criteria, etc. More recent evidence suggests that the vast majority of patients without pre-existing disease recover cognition in the long term. In fact, there are studies that suggest that in some cases surgery improves cognitive functioning (e.g. carotid endarterectomy, weight reduction surgery, etc.). This report critically analyzes the methodological concerns of the older studies and presents current evidence rejecting the long-term POCD hypothesis. In addition, it reviews the pre-existing conditions that may result in long term POCD.