Special Issue on Postoperative Cognitive Dysfunction

Selected Reports from the Journal-sponsored Symposium ALTHOUGH described more than 50 yr ago, postoperative cognitive dysfunction (POCD) remains an enigma. The subject of a Rovenstine Lecture in 2003 and numerous panels at international meetings, POCD was again featured prominently at the American Society of Anesthesiologists Annual Meeting in October 2006 as the topic for the Journal’s sponsored symposium. Each of the keynote speakers graciously agreed to be recorded and to provide their slides, and we are pleased to offer their presentations as a Web Enhancement to this month’s issue of ANESTHESIOLOGY. Also in this issue of the Journal are POCD-related review articles, as well as articles that have evolved from posters presented at the symposium. Opening up proceedings at the Journal’s sponsored symposium was Lars S. Rasmussen, M.D., Ph.D., Associate Professor, Department of Anesthesia, Centre of Head and Orthopaedics, Copenhagen University Hospital, Copenhagen, Denmark. Also the highly regarded leader of the International Study of Postoperative Cognitive Dysfunction (ISPOCD) group, he was tasked with addressing four questions: (1) Does POCD exist after noncardiac surgery? (2) If so, what is the incidence? (3) Which risk factors have been identified? and (4) Is the incidence affected by the choice of the anesthetic technique (general vs. regional)? The existence of POCD has been challenged; the hypothesis that the care associated with a surgical intervention produces a greater decline in cognitive performance than could have been expected to occur had these surgically scheduled patients not undergone surgery has never been formally tested. Absent a control group of surgical patients randomized to nonsurgical care, investigators have sought a variety of less appropriate alternatives, including age-matched healthy controls, or disease-matched patients who do not undergo the surgical procedure because of the choice of the patient or the surgeon. At the poster session that accompanied the Journal-sponsored symposium, Saager et al. reported their preliminary findings obtained from the Alzheimer’s Disease Research Centre’s database. The annual rate of cognitive decline was accelerated in an aged population after a major noncardiac surgical intervention when compared with a similar cohort, prospectively followed for at least 3 yr, who did not require a surgical intervention. Epidemiologic studies of this type are likely to shed light on the question of whether cognitive decline in surgical settings differs from the apparent decline experienced by aged patients receiving care for major medical illnesses. Stanton Newman, D.Phil., Professor and Director, Center for Behavioral and Social Science in Medicine, Royal Free and University College of London Medical School, London, England, addressed methodologic aspects in the diagnosis of POCD. Coming from the doyen of behavioral psychologists in this field, Dr. Newman identified problems in the realm of testing and analysis of the neurocognitive data sets. These are further elaborated in a review article by Newman et al. in this issue of the Journal. Mark Newman, M.D., Merel H. Harmel Professor of Anesthesiology, Chief, Division of Anesthesiology Cardiac Service, Chair, Department of Anesthesiology, Duke University Medical Center, Durham, North Carolina, is a pioneer in the field of POCD after cardiac surgery. He suggested that the distinction between cardiac and noncardiac POCD may be more apparent than real and raised the likelihood that these two artificially separated conditions may be governed by similar etiologic factors and pathogenic mechanisms. Previously, Newman et al. had provided data that demonstrate the independent adverse effect that POCD has on long-term morbidity and mortality. More recently, Newman’s group has reported on the deterioration in quality-of-life indices that occurs in patients with POCD. The panelists agreed that POCD does indeed exist as an often subtle persistent deterioration in cognitive performance (including one or more of memory, attention, and speed of information processing) after a surgical intervention; its assessment requires neuropsychological testing, and it is diagnosed by applying firm criteria to yield a dichotomous result. Thereafter, there was lively debate regarding when the change in cognitive performance between two time points separated by a surgical intervention constitutes POCD. Specific issues addressing the degree of change, together with the timing, type, and analysis of the neurocognitive battery of tests, were explored in depth without reaching a consensus view. In a fascinating mechanistic study, Wan et al. subjected anesthetized rats to splenectomies and demonstrated that there was a brief period of cognitive dysAdditional material related to this article can be found on the ANESTHESIOLOGY Web site. Go to http://www.anesthesiology. org, click on Enhancements Index, and then scroll down to find the appropriate article and link. Supplementary material can also be accessed on the Web by clicking on the “ArticlePlus” link either in the Table of