Effects of Combined and General Anesthesia on Cognitive Functions for Patients Undergoing Cardiac Surgery Under CPB

Abstract

Background: Patients may experience a variety of neurological complications after heart surgery. The most common complication observed in clinical practice is delayed neurocognitive recovery (dNCR). The role of the anesthesiologist is very important, as the risk of dNCR may be reduced, depending on the anesthesia tactic chosen. Although the possibility that neuropsychological complications are less common in patients undergoing combined anesthesia (general + epidural) than in patients undergoing general anesthesia is not yet confirmed, the results are being discussed. The aim of this study was to determine impact of combined anesthesia (general + epidural) on cognitive functions of patients after cardiac surgery. Methods: The prospective, case-controlled study included 80 patients undergoing cardiac surgery from 2015 to 2017 at the Department of Cardiothoracic and Vascular Surgery in the Hospital of Lithuanian University of Health Sciences Kauno Klinikos. After approval from the local bioethics center, informed consent was obtained from all study participants. Inclusion criteria were age 51 to 80 years, elective cardiac surgery, left ventricular ejection fraction > 35%, anamnesis of not using agents affecting the central nervous system, absence of neuropathology, and sufficient renal function. Exclusion criteria were patients suffering from diseases causing cognitive function or using agents affecting the central nervous system, emergency or re-surgery, carotid artery atherosclerosis with artery diameter 50 or more percent reduction, and a patient’s disagreement. MMSE test and 6-CIT test were used for a cognitive function assessment, Trail making test and WAIS Digital Symbol Substitution test were used for psychomotor function assessment. All tests were used a day before surgery and seven days after surgery. According to the planned anesthesia, patients were assigned into two groups: 1 – combined general + epidural anesthesia and 2 – general anesthesia. Standardized protocol of anesthesia was followed for all patients. Preoperative patients and surgery factors, preoperative and postoperative neuropsychological test results were recorded. Results: Eighty patients were enrolled in the study. Both groups did not differ in demographic, perioperative values, and baseline (preoperative) test results. Postoperative (7th day) WAIS (P = .042) and 6-item cognitive impairment (P = .016) test results were statistically different when comparing the GA and CA groups. Comparing preoperative and postoperative test results, there was a significant decline in the WAIS test score in the GA group (P = .013).