Evaluation of endovenous sedation using BIS monitoring in dentistry. A systematic review

Correlating the Depth of Sedation Between the Ramsay Sedation Scale and Bispectral Index Using Either Intravenous Midazolam or Intravenous Propofol in Elderly Patients Under Spinal Anaesthesia

BACKGROUND

Supplementation of spinal anaesthesia with sedatives or anxiolytics has emerged as a standard protocol to alleviate patients' anxiety and to produce amnesia during the surgical procedure. Thus, judicious use of sedation can make surgeries under spinal anaesthesia more comfortable and acceptable for the elderly patient, the surgeon, and the anaesthesiologist. However, over-sedation may jeopardise the safety of the patient. Appropriate sedation helps reduce physiological stress, which leads to a better result. Therefore, monitoring the depth of sedation becomes essential. The Ramsay sedation scale (RSS) and bispectral index (BIS) both are used widely to assess the depth of sedation.

OBJECTIVES

The primary objective of the study was to assess and correlate the depth of sedation between the BIS and RSS in elderly patients using midazolam and propofol under spinal anaesthesia. The secondary objectives were to observe any difference in the commencement of sedation between the two groups and to observe haemodynamic changes between the two groups.

METHODS

A total of 60 elderly patients undergoing urological procedures under spinal anaesthesia were randomly assigned to receive either midazolam (Group A, n=30) or propofol (Group B, n=30) for sedation. In Group A, patients were given an initial bolus of midazolam 0.03 mg/kg and a maintenance incremental bolus of 0.01 mg/kg up to a maximum of 2.5 mg in 10-minute intervals. Group B used propofol with an initial bolus dose of 0.5 mg/kg over two minutes and a maintenance bolus of 10-20 mg as required for the maintenance of sedation depth. Sedation was titrated to achieve a BIS score of 70-80 and an RSS score of 3-4. Heart rate, non-invasive systolic, diastolic, mean arterial blood pressure, oxygen saturation (SPO2), and the correlation coefficient between the BIS and RSS were measured at 0 (baseline), 5, 10, 20, 30, 40, 50, and 60 minutes of interval.

RESULTS

The correlation coefficient between the BIS and RSS scores in Group A at various time intervals indicate a strong correlation coefficient of -0.76 at five minutes, -0.64 at 20 minutes, -0.78 at 30 minutes, -0.56 at 40 minutes, and -0.39 at 50 minutes. In Group B, the correlation coefficient between the BIS and RSS scores at various time intervals indicate a strong correlation coefficient of -0.75 at five minutes, -0.76 at 20 minutes,-0.64 at 30 minutes, -0.89 at 40 minutes, and -0.46 at 50 minutes of interval. We also observed that the BIS drops to a lower level in patients receiving propofol (Group B) with a significant difference depicting early onset of sedation with propofol. In Group B, HR and MAP were significantly less than those of Group A. There was no significant difference in terms of mean age, sex, and body weight in the patients of both groups.

CONCLUSION

The BIS and RSS scores indicate a strong correlation with a magnitude of 70%-80%, but more in Group B (propofol) than Group A (midazolam). Therefore, the characteristics of each sedative drug can influence the level of sedation during spinal anaesthesia. Clinicians should use a combination of BIS values and other objective sedative methods to determine the degree of sedation, rather than relying exclusively on BIS values.

Efficacy and safety of remimazolam besilate for sedation in outpatients undergoing impacted third molar extraction: a prospective exploratory study

BACKGROUND

Dental treatments often cause anxiety, fear, and stress in patients. Intravenous sedation is widely used to alleviate these concerns, and various agents are employed for sedation. However, it is important to find safer and more effective sedation agents, considering the adverse effects associated with current agents. This study aimed to investigate the efficacy and safety of remimazolam besilate (hereinafter called "remimazolam") and to determine the optimal dosages for sedation in outpatients undergoing dental procedures.

METHODS

Thirty-one outpatients aged 18-65 years scheduled for impacted third molar extraction were included in the study. Remimazolam was administered as a single dose of 0.05 mg/kg followed by a continuous infusion at a rate of 0.35 mg/kg/h, with the infusion rate adjusted to maintain a sedation level at a Modified Observer's Assessment of Alertness/Sedation (MOAA/S) score of 2-4. The primary endpoint was the sedation success rate with remimazolam monotherapy, and the secondary endpoints included induction time, recovery time, time until discharge, remimazolam dose, respiratory and circulatory dynamics, and frequency of adverse events.

RESULTS

The sedation success rate with remimazolam monotherapy was 100%. The remimazolam induction dose was 0.08 (0.07-0.09) mg/kg, and the anesthesia induction time was 3.2 (2.6-3.9) min. The mean infusion rate of remimazolam during the procedure was 0.40 (0.38-0.42) mg/kg/h. The time from the end of remimazolam administration to awakening was 8.0 (6.7-9.3) min, and the time from the end of remimazolam administration to discharge was 14.0 (12.5-15.5) min. There were no significant respiratory or circulatory effects requiring intervention during sedation.

CONCLUSIONS

Continuous intravenous administration of remimazolam can achieve optimal sedation levels without significantly affecting respiratory or circulatory dynamics. The study also provided guidance on the appropriate dosage of remimazolam for achieving moderate sedation during dental procedures. Additionally, the study findings suggest that electroencephalogram monitoring can be a reliable indicator of the level of sedation during dental procedural sedation with remimazolam.

TRIAL REGISTRATION

The study was registered in the Japan Registry of Clinical Trials (No. jRCTs061220052) on 30/08/2022.

Comparison of bispectral index and patient state index as measures of sedation depth during surgeries using remimazolam tosilate

BACKGROUND

The Bispectral Index (BIS) and the Patient State Index (PSI) are commonly used measures to assess intraoperative sedation depth. However, model differences lead to different results, which in turn interferes with clinicians' judgment on the depth of anesthesia. Remimazolam tosilate (RT) for injection is a new benzodiazepine used in sedation. In its clinical application, there are few effective indicators for sedation depth monitoring. To close this gap, this study aims to compare BIS and PSI in measuring the sensitivity and specificity of intraoperative RT and to explore the safety of RT for intraspinal anesthesia in elderly patients.

METHODS

This study included 40 patients undergoing elective electro-prostatectomy with intraspinal anesthesia, who were monitored by BIS and PSI simultaneously during operation. Remimazolam tosylate 0.1 mg/kg was intravenously administered after the intraspinal anesthesia when patients were in a completely painless status. Then BIS, PSI, the Modified Observer's Assessment of Alertness and Sedation (MOAA/S) scores and vital signs were observed and recorded per minute for 10 min. Pearson's correlation analysis and linear regression model were used to compare BIS and PSI sedation scores, and to test their associations with the MOAA/S score, respectively. ROC curves were drawn to compare the sensitivity and specificity of BIS and PSI. Changes of vital signs were presented as mean ± standard deviation. Perioperative liver and kidney function indicators were analyzed using a paired t-test to evaluate the safety of RT for intraspinal anesthesia in the elderly patients.

RESULTS

According to Pearson's correlation analysis, a significant (P < 0.01) correlation between BIS and PSI was found when used to monitor intraoperative sedation of RT (r = 0.796). Significant associations between BIS and MOAA/S (r = 0.568, P < 0.01), and between PSI and MOAA/S (r = 0.390, P < 0.01) were also found. The areas under the ROC curves of BIS and PSI were 0.801 ± 0.022 and 0.734 ± 0.026, respectively, suggesting that both measures may predict patients' state of consciousness and BIS was more accurate than PSI. Vital signs remained stable throughout the study. No abnormal changes of clinical significance were found based on laboratory test results of liver and kidney function.

CONCLUSION

BIS and PSI are strongly associated for monitoring the sedation of RT intraoperatively. Both methods can accurately reflect sedation depth. According to correlation analyses with MOAA/S scale and ROC curves, BIS is more accurate than PSI during such intraoperative monitoring. In addition, RT can be safely used in elderly patients under intraspinal anesthesia for supportive sedation, with stable vital signs and sound kidney and liver safety profiles.

TRIAL REGISTRATION

http://www.chictr.org.cn (ChiCTR2100051912).