The clinical Effectiveness of the Bispectral Index (BIS) to Reduce the Risk of Awareness for Elective Surgical Patients Undergoing General Anesthesia. A prospective, Randomized, Double-Blind, Controlled trial
Aidah Alkaissi*¹, PhD Tasneem Tarayra²MSN, Abdelbaset Nazzal, MD³
¹* Faculty of Medicine and Health Sciences, Nursing and Midwifery Department, An-Najah National University, Nablus-Palestine
²Faculty of Graduate Studies, An-Najah National University, Nablus- Palestine
³ An-Najah National University Hospital, Nablus-Palestine
Background: intra-operative awareness is a serious complication of general anesthesia. Bispectral Index (BIS) monitoring has been shown to decrease awareness. Aims of the study to evaluate the clinical impact of BIS monitoring to reduce the incidence of awareness and its impact on hemodynamic parameters, drug consumption, the recovery time and the end-tidal concentration of volatile anesthetics in adult patients undergoing various types of surgery under general anesthesia.
Materials & Methods: a prospective, randomized, double-blind trial. Patients were randomized for BIS-anesthesia group (n = 30), or routine care (RC) (n = 29). Statistical measures: Frequencies and percentages, mean and standard deviation. Mann-Whitney Test of differences in all quantitative variables and Chi Square Test of Association between each categorical variable and the group type.
Results: No case of awareness was reported in the BIS-guided group but 4 reports (13.8%) in the control group (P = 0.035), BIS-guided anesthesia decreased awareness by 13.8% (95% CI (1.3% - 26.4%).
There was a significant difference in the used dose of Fentanyl® for the BIS group (115.56 ±94.18 mcg and the RC group (77.76 ±40.52 mcg), P= 0.035. There is a statistically significant difference between the two groups in the time to discharge from the PACU at 12.38 ±4.989 minutes for the RC group and 9.23 ±3.819 minutes for the BIS group, P= 0.007.
Conclusions: BIS-guided anesthesia reduced the risk of awareness compared to routine care. The main reason for the occurrence of awareness in the RC group could be due to a light general anesthetic.
Key words: Awareness, general anesthesia, BIS, monitorin