Subjects who meet the study criteria and has signed the inform consent will be randomized in a 1:1 ratio into 2 groups, namely Group A undergoing general anesthesia with additional BIS monitoring. When the patient arrives in the preparation room approximately 1 hour before surgery, MMSE evaluation is conducted to obtain preoperative MMSE data. Before anesthesia induction, monitoring and BIS sensor placement are performed

Subjects who meet the study criteria and has signed the inform consent will be randomized in a 1:1 ratio into 2 groups, Group B undergoing general anesthesia with standard monitoring according to ASA. When the patient arrives in the preparation room approximately 1 hour before surgery, MMSE evaluation is conducted to obtain preoperative MMSE data. The BIS monitor for patients in Group B is then covered (hidden BIS), so that the data cannot be viewed by the anesthesia team performing the anesthesia

Bispectral Index (BIS), that was introduced in 1992, is a tool that monitors the depth level of hypnosis through data processing of an electroencephalogram using computer algorithm and presented in the form of processed EEG. Utilizing BIS as a monitoring tool has shown effectiveness in reducing recovery time, prevent awareness, and bring down the amount of anesthesia agent however, as of now, it has not been incorporated into the 2020 American Society of Anesthesiologists (ASA) standard procedure on anesthesia monitoring. aims to comparing the deep hypnotic time duration on two group of geriatric patients which undergoes general anesthesia with BIS monitoring compared to standard monitoring.

Deep Hypnotic Time is the period during the Bispectral Index (BIS) are extensively less than 40 (a scale of 0 - 100). The BIS value that is believed to prevent 50% of the population from responding to verbal instructions placed on an index value of 67 - 79. Targeted BIS value to prevent awareness under general anesthesia are at a range of 40 - 60. A study conducted using BIS, shows that under a standard care, BIS value during operative maintenance period tends to be lower which sat around 36 (31 - 49). Duration is the lower the DHT duration the better the outcome of the patient, duration is measured in minutes

patients mental state is examined by using MMSE test to find an objective screening method of cognitive function (lost score = 0, maximum score = 40), scoring category : 0 - 10 MMSE Score = Severe Cognitive Impairment 10 - 20 MMSE Score = Moderate Cognitive Impairment 20 - 25 MMSE Score = Mild Cognitive Impairment 25 - 30 MMSE Score = Questionably Significant / Maybe Normal Cognitive