| Abstract |
Postoperative disturbances of mental function are a very common complication of elderly patients undergoing major surgery, with a prevalence of 5-50%. The predisposing factors of this phenomenon are not well investigated. The aim of this study was to examine a) whether the type of anaesthesia (regional or general) affects the incidence of delirium and the recovery of gross mental function with the use of DSM IV criteria for delirium and the Mini Mental State Examination respectively, during the immediate postoperative period and b) the effects of the type of anaesthesia on the incidence of early (at one week) and late (at three months after surgery) Postoperative Cognitive Dysfunction (POCD) with the use of four psychometric tests: Visual Verbal Learning Test - VLT, Concept Shifting Task - CST, Stroop Color Word Test - STR and Letter-Digit Coding Test - LDC. Forty seven patients aged over 60 undergoing surgery that could be performed under regional or general anaesthesia were included in the study. The patients that entered the study were randomized into two groups to receive either regional or general anaesthesia. Times of psychometric assessment: All patients were subjected to the aforementioned tests on the preoperative day. The incidence of delirium and the gross mental status of the patients, as assessed with the MMSE, during the first three postoperative days were recorded. Concerning the incidence of POCD, the patients were subjected to VLT, CST, STR and LDC tests at the end of the first week and at three months after the operation. Postoperative Cognitive Dysfunction was defined as the significant decline on at least two postoperative psychometric tests. The incidence of delirium during the first three postoperative days was 19% (14-24%). The factors that were found to be significant for the development of delirium were pre-existing cardiovascular disease (P = 0.025) and a high level of education (P = 0.02). Overall, during the first three postoperative days, the mean Mini Mental State Examination score decreased significantly (p £ 0.0008). However, this decline was very significant only in patients assigned to receive general anaesthesia (p < 0.00001) compared to regional. The incidence of early POCD was 21.3% (13.3-29.3%). The incidence of early POCD was significantly greater after general anaesthesia (32% [15 - 49%]) compared to regional anaesthesia (5,3% [0,3-10,3%]) (p =0.034). Also, the duration of anaesthesia of more than two hours and a significant decline on at least one postoperative MMSE were related to early POCD (p = 0.0032 and P =0.02 respectively). Three patients that underwent general anaesthesia developed late POCD (7% [2 -12%]). In conclusion, patients with a history of pre-existing cardiovascular disease developed postoperative delirium more frequently. Delirium in the postoperative period in most cases was a mild disturbance of behavior that recovered without any special intervention. The mental function of patients undergoing major non-cardiothoracic surgery recovered earlier after regional anaesthesia. The incidence of early Postoperative Cognitive Dysfunction was lower after regional anaesthesia and the same trend was seen for late POCD.
|
Επίδραση του είδους της αναισθησίας στην εμφάνιση μετεγχειρητικής νοητικής δυσλειτουργίας στους ηλικιωμένους
