The use of bispectral analysis in patients undergoing intravenous sedation for third molar extractions

doi:10.1016/S0278-2391(00)90911-X

Journal of Oral and Maxillofacial Surgery

Volume 58, Issue 4, April 2000, Pages 364-368

https://doi.org/10.1016/S0278-2391(00)90911-X Get rights and content

Abstract

Purpose:The bispectral (BIS) index has been used to interpret electroencephalogram (EEG) recordings to predict the level of sedation and loss of consciousness in patients undergoing general anesthesia. It was the purpose of this project to assess the usefulness of BIS technology in determining the level of sedation in patients undergoing third molar extraction under conscious sedation.

Patients and Methods: Twenty-five subjects undergoing third molar extraction in an outpatient setting were analyzed. The EEG activity was recorded continually during surgery using a microcomputer (Aspect-1050 Monitor; Aspect Co, Natick, MA) with real-time bispectral data obtained by EEG skin electrodes through a frontotemporal montage. The Observer's Assessment of Alertness and Sedation (OAA/S) scale was used to subjectively assess the level of sedation observed by the anesthetist before initiating the sedation procedure and then at 5-minute intervals until the end of the procedure. The BIS level was simultaneously recorded. The initial sedation was accomplished using a standard dose of midazolam (0.05 mg/kg) and fentanyl (1. 5 μg/kg) followed by a 10- to 30-mg bolus of propofol until a level of sedation at which the patient's eyes were closed and he or she was responsive only to vigorous stimulation or repeated loud calling of their name (OAA/S level of 1 to 2). Local anesthesia was then administered. Additional doses of sedative medication (midazolam or propofol) were given during the procedure to maintain the desired level of sedation (an OAA/S level of 2 to 3). The time and dose of the drug given were recorded. The level of sedation based on a single anesthetist's interpretation (OAA/S) and the BIS readings were then compared.

Results:A strong positive relationship between the BIS index and OAA/S readings was found (P < .0001). Pairwise comparisons of mean BIS index and its corresponding OAA/S level were significantly different from each other (P < .003) except for OAA/S levels 2 and 3 (P = .367). Conclusion:BIS technology offers an objective, ordinal means of assessing the depth of sedation. There was a strong relationship between the objective BIS values and subjective assessment (OAA/S scale) of the depth of anesthesia. This can be invaluable in providing an objective assessment of sedation in oral and maxillofacial surgery where it may be difficult to determine the level of sedation clinically.

References (10)

M.N. Avramov et al.
Methods for monitoring the level of sedation
Crit Care Clin
(1995)
D.Y. Wang et al.
Respiraton sinus arryth-mia: A new, objective sedation score
Br J Anaesth
(1993)
D.A. Chernik et al.
Validity and reliability of the observers assessment of alertness/sedation scale: Study with intravenous midazolam
J Clin Psychopharmacol
(1990)
P.S. Glass et al.
Bispectral analysis measures sedation and memory effects of propofol, midazolam, isoflurane, and alfentanil in healthy, volunteers
Anesthesia
(1997)
J.C. Sigl et al.
An introduction to bispectral analysis for the encephalogram
J Clin Monit
(1994)

There are more references available in the full text version of this article.

Cited by (57)

Loading dose of Dexdor<sup>®</sup> and optimal sedation during oral and maxillofacial ambulatory surgery procedures: An observational study
2017, Revista Espanola de Anestesiologia y Reanimacion
El objetivo de este estudio fue evaluar el efecto de diferentes dosis de carga de dexmedetomidina (formulación Dexdor^®) en el tiempo para lograr y mantener un nivel óptimo de sedación, y su repercusión hemodinámica.
Estudio observacional aprobado por el CEIC-Navarra en pacientes programados para cirugía oral y maxilofacial ambulatoria con dexmedetomidina en la Clínica Universidad de Navarra entre febrero de 2013 y noviembre de 2014. En función de la dosis de carga los pacientes fueron agrupados en 3 categorías: < 0,5; 0,5; y > 0,5 μg/kg. El nivel óptimo de sedación se definió como un índice biespectral < 85. Los datos se analizaron utilizando técnicas de análisis de supervivencia. Los requerimientos de fármacos vasoactivos fueron evaluados mediante regresión logística exacta.
Ochenta y un pacientes fueron evaluados. La hazard ratio de alcanzar un índice biespectral < 85 para los pacientes de los grupos de 0,5 y > 0,5 μg/kg fue de 1,5 (IC 95% 0,9; 2,6) y 1,8 (IC 95% 0,8; 3,9), respectivamente, en comparación con el grupo inferior. Cinco pacientes (6,2%) precisaron de atropina. Los pacientes en el grupo de > 0,5 μg/kg mostraron mayor riesgo de requerir atropina respecto al grupo de < 0,5 μg/kg (odds ratio 2,2; IC 95% 0,03; 183).
Una dosis de carga de Dexdor^® > 0,5 μg/kg parece reducir el tiempo necesario para alcanzar y mantener un nivel óptimo de sedación durante los primeros 60 min de procedimiento. La posible relación entre la dosis de carga y los requerimientos de atropina precisa una investigación más exhaustiva.
Dexdor^® do not include the possibility of loading dose, which could increase time to achieve adequate sedation for ambulatory procedures. The objective of this study was to evaluate the effect of several loading dose of dexmedetomidine in the time to achieve and maintain an optimal level of sedation and its clinical hemodynamic repercussion.
The IRB approved this observational study for patients that underwent oral and maxillofacial ambulatory surgery under dexmedetomidine at the University of Navarra Clinic from February 2013 to November 2014. According to the loading dose the patients were grouped into 3 categories: < 0.5, 0.5, and > 0.5 μg/kg. Optimal level of sedation was defined as bispectral index < 85. Data were analyzed using survival analysis techniques. Vasoactive drugs requirements was evaluated using exact logistic regression.
Eighty-one patients were evaluated. Hazard ratios for patients in 0.5 and > 0.5 μg/kg loading dose categories for achieving a bispectral index < 85 were 1.5 (95% CI 0.9, 2.6) and 1.8 (95% CI 0.8, 3.9), respectively, compared with the lowest category. Five patients (6.2%) required atropine for bradycardia. Patients in the group > 0.5 μg/kg showed greater risk of requiring atropine compared with the group < 0.5 μg/kg (odds ratio 2.2; 95% CI 0.03, 183).
Loading dose of dexmedetomidine > 0.5 μg/kg appears minimize the time to achieve and maintain an optimal level of sedation during the first 60 min of procedure. Further investigation to elucidate the association between loading dose of dexmedetomidine and subsequent atropine requirements may be warranted.
Asleep-awake-asleep regimen for epilepsy surgery: A prospective study of target-controlled infusion versus manually controlled infusion technique
2016, Journal of Clinical Anesthesia
Asleep-awake-asleep (AAA) protocol for epilepsy surgery is a unique opportunity to accurately map epilepsy foci involved in motor and eloquent areas, allowing the operator to optimize the resection. Two different application modes of intravenous anesthesia for AAA craniotomies are widely used: infusion by means of target-controlled infusion (TCI) and traditional manually-controlled infusion (MCI). We conducted this study to examine whether intravenous anesthesia using the TCI system with propofol and remifentanil would be a more effective method than MCI in AAA epilepsy surgery.
This prospective and single center study compared patients undergoing either TCI or MCI techniques for functional AAA epilepsy surgery. 35 cases used TCI including TCI-E (resection of epileptogenic foci in an eloquent area, n = 18) and TCI-M (resection of epileptogenic foci in a motor area, n = 17). Thirty-six cases used MCI including MCI-E (epileptogenic foci in an eloquent area, n = 16) and MCI-M (epileptogenic foci in a motor area, n = 20). Bispectral index value and hemodynamic profiles at different time points during the awake phase were recorded along with time for awakening and the occurrences of adverse events.
The TCI technique significantly shortened intraoperative awakening times during the third phase, TCI-E vs MCI-E 12.82 min ± 6.93 vs 29.9 min ± 9.04 (P = .000) and TCI-M vs MCI-M 16.8 min ± 5.19 vs 30.91 min ± 15.32 (P = .010). During the awake phase, the highest bispectral index score values appeared in the TCI-E group at all-time points. Mean arterial pressure and heart rate were more stable in the TCI-E group compared with the MCI-E group during the awake phase. Tachycardia and hypertension were most common in the MCI-E group (52.9% and 29.4%, P = .001 and P = .064).
We found the superiority of TCI, which is faster intraoperative awakening and better hemodynamics along with secure airway management conditions. It is suggested that the TCI technique may be a feasible and effective technique and it might be a viable replacement of the MCI technique for AAA epilepsy surgery.
Monitoring and delivery of sedation
2014, British Journal of Anaesthesia
Citation Excerpt :
Processed EEG monitors, such as the bispectral index monitor (BIS™, Covidien, Inc., Boulder, CO, USA), have been evaluated to determine their efficacy in monitoring the depth of sedation. Multiple observational studies have correlated processed EEG indices with the MOASS, RSS, or the ASA Continuum of Sedation during sedation in volunteers15 16 and in patients undergoing sedation in a variety of clinical settings, such as endoscopy suites,17 18 dental offices,19 the emergency department,13 20 and the operating theatre.21 22 Uniformly, these studies find a significant correlation between the processed EEG index and the sedation scale.
Sedation for medical procedures is provided in a variety of clinical settings by medical personnel with differing levels of education and training. Although generally a safe practice, there is a degree of morbidity and mortality associated with sedation practice. Monitoring standards continue to be refined by professional societies with the goal of improving care. The depth of sedation should be monitored with clinical criteria. Processed electroencephalographic monitors currently do not contribute significantly to sedation care. Monitoring ventilation using pulse oximetry should be abandoned for more direct methods, such as capnography-transcutaneous carbon dioxide, respiratory acoustical and thoracic impedance monitoring could also play a role. Propofol has become widely utilized for sedation, although there are concerns about its margin of safety and synergistic interactions with other agents. Dexmedetomidine and propofol/ketamine also have utility. Patient-controlled sedation pumps and target-controlled infusion devices have been developed to improve patient care and satisfaction. A computer-assisted propofol sedation device to be used by non-anaesthesiologists has been approved in the USA by the Food and Drug Administration. More computer-assisted sedation delivery devices are likely to be developed, but their clinical utility is unclear.
The effect of nitrous oxide inhalation on the hypotensive response to propofol: A randomized controlled trial
2014, Oral Surgery, Oral Medicine, Oral Pathology and Oral Radiology
Decrease in arterial blood pressure is a prominent adverse reaction during propofol (Disoprivan; AstraZeneca K.K., Osaka, Japan) sedation. The purpose of this prospective randomized study was to explore the effects of nitrous oxide (N₂O) on the hypotensive response during propofol sedation.
Twenty-six healthy volunteers received intravenous sedation with propofol alone (group P, n = 13) or a combined technique using 20% N₂O and propofol (group N + P, n = 13). Propofol was administered by a target-controlled infusion system to attain and maintain a plasma propofol concentration of 1.5 μg/mL. Hemodynamic and autonomic parameters were measured.
Mean arterial pressure decreased in both groups, the hypotensive response in group N + P being significantly smaller than in group P. Reduction in the low-frequency power of systolic blood pressure variability, indicative of sympathetic nervous activity, was also smaller in group N + P than in group P.
Addition of N₂O to propofol sedation can attenuate the hypotensive effect of propofol.
Comparison of dexmedetomidine and midazolam for conscious sedation in dental surgery monitored by bispectral index
2013, British Journal of Oral and Maxillofacial Surgery
Although various sedative drugs in different regimens and given by different delivery routes have been used for conscious sedation, the ideal agent and regimen remain to be established. This study was designed to compare the efficacy (sedation, anxiolysis, analgesia, operating conditions, and patients’ satisfaction) and safety of midazolam and dexmedetomidine as sedatives for dental procedures in a randomised, double-blind study in third molar and dental implant surgery. Sixty healthy patients who were American Society of Anesthesiologists (ASA) group I or II were enrolled and we recorded their personal details, the amount of drug used, their degree of satisfaction, duration of operation, and haemodynamic and respiratory variables. The two groups were comparable. The amount of local anaesthetic (p = 0.11) and the duration of operation did not differ significantly (p = 0.32). The patients in the dexmedetomidine group had a slower heart rate, lower systolic and diastolic pressure, and cooperated better. There were no significant differences in their respiratory rates, bispectral index, and total volume of drugs used. We conclude that dexmedetomidine works as well as midazolam for outpatient dental procedures and can be used as an alternative to midazolam.
Midazolam increases bite force during intravenous sedation
2012, Journal of Oral and Maxillofacial Surgery
Citation Excerpt :
The bispectral index (BIS) value was monitored continuously with an A-2000 monitor (XP 3.23, Aspect Medical Systems, Newton, MA) to assess the sedation level. The Observer's Assessment of Alertness/Sedation (OAA/S)24,25 scale was also used. The Stroop color word test (SCWT)26,27 was used to assess cognitive judgment function.
Although there have been many reports on the effects of midazolam on vital function and the recovery profile, little is known about muscle power during sedation. The purpose of this study was to investigate the effects of midazolam on muscle power during moderate sedation.
The subjects were 20 male volunteers classified as American Society of Anesthesiologists physical status I. Each subject underwent 2 experiments in a randomized crossover manner (midazolam and control groups). After baseline data were obtained, midazolam (0.05 mg/kg) was administered. Thirty minutes after midazolam administration, flumazenil (0.5 mg) was administered to antagonize the sedative effects of midazolam in the midazolam group. Heart rate, noninvasive blood pressure, arterial oxygen saturation, respiratory rate, and the bispectral index value were monitored. The Observer's Assessment of Alertness/Sedation scale and the correct-answer rate of the Stroop color word test were assessed. To evaluate muscle power, grip strength and bite force were measured. After baseline measurement, all variables were measured 2, 5, 10, 20, and 30 minutes after midazolam administration and 5, 10, and 20 minutes after flumazenil administration. For statistical comparisons, repeated measures analysis of variance, the Friedman χ² test, and the Student t test for paired samples were used.
No significant changes were observed for any variable in the control group. In the midazolam group, the bispectral index value and the Observer's Assessment of Alertness/Sedation scale decreased during midazolam sedation. The correct-answer rate of the Stroop color word test decreased 5 and 10 minutes after midazolam administration. Grip strength decreased during midazolam sedation. Bite force increased immediately after midazolam administration and remained increased even after flumazenil administration.
Although the detailed mechanisms are unknown, bite force increases despite the muscle-relaxant action of midazolam during sedation and persists even with flumazenil reversal.

View all citing articles on Scopus

^☆: Supported by the Minnesota Oral Health Clinical Research Center NIH/NIDR P30-DE09737 (B.S.S.).

^a: Received from the University of Minnesota, Minneapolis, MN.

View full text

Clinical articleThe use of bispectral analysis in patients undergoing intravenous sedation for third molar extractions☆

Abstract

Crit Care Clin

Br J Anaesth

Validity and reliability of the observers assessment of alertness/sedation scale: Study with intravenous midazolam

J Clin Psychopharmacol

Bispectral analysis measures sedation and memory effects of propofol, midazolam, isoflurane, and alfentanil in healthy, volunteers

Anesthesia

An introduction to bispectral analysis for the encephalogram

J Clin Monit

Clinical article
The use of bispectral analysis in patients undergoing intravenous sedation for third molar extractions☆