DIAGNOSTIC CRITERIA FOR POST-OPERATIVE COGNITIVE DYSFUNCTION: LITERATURE REVIEW

Abstract

In 1955, for the first time, Betford described POCD in elderly persons [2] and this way, he started a new direction for research. POCD is defined as a decline of cognitive functions following surgery at several weeks or months distance [3]. Incidence of POCD in heart surgery varies between 30% and 80% during the first postoperative week, being 60% in the following several months [4, 5]. In major, non-cardiac surgery, POCD has an incidence of 26% at one week distance after the surgery, being 10% at 3 months after the surgery [6]. Patients that showed signs of POCD at discharge, had higher mortality risks in the first 3 months of the postoperative period. According to Steinmetz et al, patients that showed cognitive impairment during 3 postoperative months as well, had higher chances to die in the first postoperative year (2009) [7]. The mechanism of POCD is not yet known, but neuro-inflammation is blamed to be one of the causes [8]. There is a variety of other factors that may contribute to the development of POCD and can’t be ignored: age, educational level, strokes [6], major surgery or history of multiple surgeries [9], genetic factors (apoprotein E) etc [10]. POCD was evaluated using batteries of neuro-psychological tests that cover several areas of cognitive functions such as reading, memorizing, orientation etc. So, the multitude of tests used by different researches raise a lot of questions: is it possible to create a single test that would reflect all areas of cognitive function? Which would be the ideal combination between these tests in order to establish POCD? Unification of these questionnaires and an ideal template has not been created yet. Thus, the proposed questionnaires need to be validated as a screening method of POCD.