Background: Bispectral index (BIS) assesses depth of anesthesia. There are controversial reports about opioids, like remifentanil, effect on BIS. At this study, the effect of different doses of remifentanil, 0.1mg/kg/min (LD) and 0.2mg/kg/min (HD) on BIS were evaluated.Materials and Method: 54 patients, ASA Class 1 or 2, age 20-60 years old who were admitted for cataract surgery under general anesthesia were selected. Induction of anesthesia: sodium thiopental 5mg/kg, succinylcholin 2 mg/kg, lidocaine 1 mg/kg and fentanil 2mg/ kg. After tracheal intubations, cisatracuriom 0.15 mg/ kg, propofol 200mg/kg/min and remifentanil HD or LD, each for 10 minutes, with randomized sequences. 4 patients were excluded because they got hypertension or tachycardia more than %20 of baseline or physical movement under general anesthesia.BIS was recorded every one minute. Comparison of mean BIS values of the two groups was made by intra group t-test.Results: Mean BIS in LD group was 51.73±5.87 and in HD group was 45.22±5.2. P-value was <0.001, so the difference was significant.Conclusion: Remifentanil combined with propofol can change BIS, so we can use BIS as an monitoring of depth of anesthesia during general anesthesia with opioids base.

Context: Bispectral Index (BIS) was introduced in 1960 to monitor the depth of anesthesia in the operating rooms. It has been recently used to monitor the sedation in the critically ill patients hospitalized in intensive care and neurocritical care units (NCCU). Evidence Acquisition: Patients in the NCCU, particularly those with prolonged mechanical ventilation require appropriate adjustments in the administration of sedative drugs. Similarly, those who require neuro protection with barbiturates need to be closely monitored in the depth of their coma. Results: BISmaybe a useful tool in this situation, andit can also help shorten the duration of mechanical ventilation by determining the appropriate time to eliminate patients from mechanical ventilation. We conducted a literature search to evaluate the utility of BIS monitoring in the NCCU patients with subarachnoid hemorrhage, intracranial hemorrhage, coma, cerebral hypoxia, status epilepticus and traumatic brain injury. Conclusions: BIS monitoring may be a useful adjunct to take care of the patients. However, further studies with a larger population and better design are required to substantiate the role of BIS monitoring in the care of NCCU patients.

BACKGROUND: Because the effects of cricoid pressure (CP) on BIS values have not been evaluated, this prospective study was designed to assess the BIS values after application of CP in adult patients during the routine induction of general anesthesia.METHODS: We randomly allocated 70 patients (ASA-I) aged 18-64 years, listed for elective surgery into two groups of cricoid (CP) and non-cricoid (nCP). In the cricoid group, bimanual cricoid pressure was performed after the induction of anesthesia and in the nCP group, simple placement of hands without exerting pressure was performed. Arterial blood pressure, heart rate and BIS were measured and recorded immediately before and after application of cricoid pressure, before laryngoscopy and intubation and then every one minute after intubation until 4 minutes. The data were compared between and within groups using the mixed-design analysis of variance.RESULTS: One minute after application of cricoid pressure and before laryngoscopy, BIS showed significantly higher value compared with the nCP group. Furthermore, one min after intubation, BIS values and arterial blood pressure increased significantly in both groups compared with the baseline values, but the increase in BIS value was more significant in CP group than nCP group. Moreover, BIS values increased significantly 2 minutes after intubation in CP group compared with nCP group.CONCLUSIONS: It was concluded that the application of CP in combination with laryngoscopy and intubation increases the BIS values, which show the inadequacy of anesthesia and hypnosis during the routine induction of anesthesia.