Investigation of the effect of anesthesia implementation with bispectral index on postoperative neurocognitive functions and delirium in open heart surgery

Abstract

Background: Neurological complications of coronary artery bypass surgery are still the major causes of mortality and morbidity despite all advances in this field.

Aims and Objectives: We investigated the effect of bispectral index (BIS) monitoring of the patient consciousness on the postoperative neurocognitive functions in our study.

Materials and Methods: A total of 40 patients in the age range from 25 to 75 years were included in our study, who were electively operated for isolated coronary artery bypass grafting (CABG) surgery in the period from January 2014 to June 2014. The patients were assigned to two groups based on whether BIS monitoring was performed or not. The patients were consecutively allocated to either group when they were found eligible to be included based on the exclusion criteria. Administration of the anesthesia was monitored with BIS in the respective group (Group 1). All patient follow-up parameters were compared in both groups. Neurocognitive function tests (the clock drawing test and standardized mini mental test) were administered to the patients in the preoperative and postoperative period(1 st day and day before discharge). The results were compared.

Results: There were no significant findings in the demographic features and the routine follow-up parameters between the two groups. The time of extubation, intensive care unit (ICU) follow-up parameters, and the length of stay in the ICU were not significantly different between the groups; however, the length of stay at the hospital was significantly longer in the group of patients, who were not monitored with BIS (p<0.05). The mean arterial blood pressure was statistically significantly higher in group 1 (BIS monitoring) at all phases of the operation and during the postoperative follow-ups. A significant acidosis was present in the arterial blood pressure tests of the patients in group 1 during their stay at the ICU. The Po2 values following cross-clamping and extubation were significantly higher in group 1. In the group monitored with BIS, the results of the neurocognitive tests, which were the clock drawing test and the standardized mini mental test, were both clinically and statistically superior (p<0.05).

Conclusıons: BIS monitoring provides favorable contributions for the follow-up of the patients undergoing CABG surgery and it is helpful in estimating the consciousness state of the patients after the surgery.