A comparison of sustainable recording between cerebral state index (CSI) and bispectral index (BIS) monitors during total intravenous anesthesia using target-controlled infusion technique for elective supratentorial craniotomy

Background: This study aimed to compare the sustainability of recording between cerebral state index (CSI) and bispectral index (BIS) monitors during supratentorial craniotomy. Methodology: A total of 42 patients for elective supratentorial craniotomy, aged 18-60 y, ASA I-II, were randomized into two groups: Group CSI (n = 21) and Group BIS (n = 21). All patients underwent surgery under the target-controlled infusion technique for propofol and remifentanil. CSI and BIS sensors were applied accordingly over the forehead before induction, and the index was continuously recorded. Anesthesia was maintained between a range of 40 and 60 in the index. The percentage and time of sustainable recording, and association with causes of unsustainable recording were documented. Results: There were no significant differences in the percentage of sustainable monitoring (66.7% vs. 71.4%; P = 0.739) and mean duration of sustainable monitoring (437.2 +/- 221.8 vs. 407.3 +/- 174.6 min; P = 0.631) between CSI and BIS. The causes of recording interruption were comparable between the two groups. Within the BIS group, there was a significant association between sustained recording and surgical incision site (p = 0.012) with the most sustainable recording was a frontoparietal incision (73.3%). Conclusion: CSI and BIS monitors were comparable in their ability to sustain a recording of index during supratentorial craniotomy.