Intraoperative Awareness and Post Operative Recall and Cognitive Dysfunction in Patients Undergoing Off Pump Coronary Artery by Pass Grafting with Intravenous Propofol v/s Dexmedetomidine - A Randomised Control Study

Background: Awareness during general anesthesia is unanticipated patient wakefulness during surgery or recall of intraoperative events. Incidence of awareness in patients undergoing cardiac surgery is significantly higher than the overall incidence of 1% during general surgery. Awareness during cardiac surgery can be prevented by supplemental, intraoperative use of sedative agents. Propofol has been shown to reduce the incidence of awareness. Dexmedetomidine is also being considered for maintaining intraoperative depth of anesthesia. Postoperative cognitive dysfunction (POCD) is a regular and well known complication after prolonged surgeries that can prolong recovery from surgery and impair quality of life in the longer term. The purpose of this study was to evaluate the effect of dexmedetomidine on depth of anesthesia and to compare it with the effect of propofol in cardiac surgery. Methodology: This was a prospective, randomized, double - blind study conducted in a tertiary - care hospital.69 patients with ASA - PS I - III planned for elective open heart surgery were randomized into three groups of 23 patients each. Each patient of the dexmedetomidine group received an initial bolus dose of dexmedetomidine at 1 mcg kg - 1 over 10 minutes followed by infusion at the rate of 0.2?0.6 mcg kg - 1 hr - 1. Patients of the propofol group received infusion at the rate of 0.25 - 1 mg kg - 1 hr - 1 and the control group were administered only isoflurane. An identical technique?of standard general anesthesia and routine physiological monitoring?was used in the three groups. Bispectralscores were recorded at predetermined intervals during surgery. The patients were assessed for awareness and recall 24 hours after tracheal extubation. Results: Intraoperative BIS scores remained within the target range; however, the BIS scores showed variable trends between the groups and were significantly lower in the dexmedetomidine group (p less than 0.001). None of the patients in the three groups had recall of intraoperative events. MMSE scores on POD 1 were found to be significantly higher in the dexmedetomidine group, suggesting lesser incidence of POCD. Conclusion: Administration of dexmedetomidine was as effective in reducing awareness and recall in cardiac surgery compared to propofol. Thus, dexmedetomidine can be used as an alternative agent to prevent awareness and recall in cardiac surgery. It was found that dexmedetomidine administration will also reduce the incidence of POCD when compared to propofol.