BRIEF SUMMARY : The Bispectral index (BIS) monitor based on the indication “to monitor the state of the brain by data acquisition of electroencephalogram (EEG) signals in the intensive care unit, operating room and for clinical research". The BIS module is a non-invasive device which consists of a sensor, a digital signal converter, and a monitor. The sensor is a single simplified strip composed of 4 electrodes placed on the patient’s forehead to pick up the electrical signals from the cerebral cortex and transfer them to the digital signal converter. The BIS device translates EEG data gathered from forehead electrodes and facilitates us with a BIS data value ranging from 0 to 100. A BIS value of 0 denotes suppressed EEG activity, and a value of 100 indicates the fully awake state. BIS values ranging between 40 and 60 is the proposed target in which the patients have minimal risk of experiencing intraoperative awareness with recall during general anaesthesia. A light plane of anesthesia can result in the recall of incidents or conversations that occurred while under anesthesia. Overly deep plane of anesthesia can also result in respiratory depression requiring respiratory assistance postoperatively. Hence, monitoring the depth of anesthesia has become increasingly necessary and remains an active area of research. BIS-guided anaesthesia in comparison to clinical signs may diminish the risk of intraoperative awareness, reduce requirement of anesthetic drugs and improve early recovery period in people undergoing surgery under general anaesthesia. The placement of electrodes in the fronto-temporal region is considered to be the gold standard for BIS monitoring. However, in some surgery cases the surgical incision site may hinder the placement of the electrodes.

HYPOTHESIS : Bispectral index values with sensor placement on the nasal dorsum site are comparable to values from standard frontal-temporal site for measuring depth of anesthesia.