Impact of combined anaesthesia on cognitive functions of patients after cardiac surgery

Abstract

The incidence of postoperative cognitive dysfunction (POCD) occurs in 30-65% of patients after cardiac surgery. The aim of our study was to investigate the impact of general anaesthesia with thoracic epidural anaesthesia on cognitive functions after cardiac anaesthesia with CPB.\nThis prospective case control study study took place at the Department of Cardiothoracic and Vascular Surgery (Medical Academy Hospital of Lithuanian University of Health Sciences) in 2014 - 2015. \n80 patients were enrolled into two groups: general anaesthesia (GA, n = 42) and general anaesthesia with thoracic epidural anaesthesia (TEA, n = 38). Neurocognitive tests were accomplished 1 day before surgery and 7 days postoperatively: MMSE, Six item cognitive impairment test, WAIS Digit symbol substitution test. \nAll preoperative (baseline) test results did not differ significantly between TEA and GA groups. 7th-day WAIS test results did not differ comparing TEA (20.03; SD 5.97) and GA (17.14; SD 6.48) groups. Comparing preoperative and postoperative WAIS test results there was a relevant decline in GA (preoperatively: 19 (SD 7.11); postoperatively 17.14 (SD 5.97) group. WAIS score change was significantly higher in GA groups, compared to TEA. There was no significant difference in 7th-day MMSE test results comparing TEA (median 28, min 23, max 30) and GA (median 28, min 18, max 30) groups. Patients in TEA group demonstrated better Six-item test results than in GA group at the 7th day after surgery (p= 0,16). Less points demonstrate better cognitive function, more points - cognitive dysfunction: GA median 2 (min 0, max 16) vs TEA median 2 (min 0, max 16) before surgery and GA median 4 (min 0, max 18) vs TEA median 2 (min 0, max 18) after surgery.