Comparative Study of Bispectral Index (BIS) Values Obtained From Standard Frontal Position and Alternative Infra-orbital Position During Total Intravenous Anaesthesia (TIVA).

The inclusion criteria were consented adults between the age of 18 and 60 years old, BMI \> 18 and \<30 kg/m2 and ASA physical status I or II underwent general elective surgery under general anaesthesia. We excluded patients who were going for neurosurgery, maxillofacial or facial surgical procedures because the operation site may interfere with the BIS sensors placement. Patients with a history of disabling central nervous or cerebrovascular disease, those on psychiatric medication or central nervous system active drugs, and those who had undergone neurosurgical procedure were also excluded. The patient who had interruption of BIS monitoring of any BIS sensor location at any time frame will be withdrawn from the study.