Abstract: Objective To explore the differences between various monitoring methods of anesthetic depth during total knee arthroplasty under general anesthesia combined with ultrasound-guided femoral nerve block.Methods From January 2021 to March 2021,60 patients undergoing total knee arthroplasty under ultrasound-guided femoral nerve block combined with general anesthesia were randomly divided into IoC group and BIS group,30 cases in each group.IoC group awareness index (Index of Consciousness,IoC) monitoring;bIS group was monitored by bispectral index (BIS) to guide the use of sedative and analgesic drugs during operation.The primary outcome measure was the time of first eye opening,and the secondary outcome measures included the average target concentration of sedative and analgesic drugs during operation,the number of perioperative adverse events and the quality of recovery.ResultsThe average difference in the first eye opening time between the two groups was 1.57 min (95% confidence interval:-0.61~2.63).The upper limit of the 95 % confidence interval was 2.63 min,which was less than the non-inferiority boundary value (δ=2.8 min),suggesting that the non-inferiority hypothesis of the main efficacy indicators was established.There was no significant difference in the dosage of propofol and sufentanil and the quality of recovery between the two groups (P>0.05).The target-controlled concentration of remifentanil in IoC group (8.55±1.45)ng/ml was significantly higher than that in BIS group (4.62±0.96) ng/ml,and the difference was statistically significant (P<0.05).At the same time,compared with BIS group,the number of stress hypertension (10 vs 32) in IoC group was significantly reduced and the number of bradycardia (17 vs 6) was significantly increased,the difference was statistically significant (P<0.05).At the same time,no intraoperative awareness and body movement were found in both groups.Conclusion During total knee arthroplasty surgery under general anesthesia combined with ultrasound-guided femoral nerve block:1.IoC monitoring is not inferior to BIS monitoring in terms of awakening speed and quality.2.The increased use of remifentanil in the IoC group and the reduced incidence of hypertension may indicate that IoC monitoring is more sensitive to intraoperative nociceptive stimuli.

Key words: anesthesia depth monitoring, electroencephalography, bispectral index monitoring