Association between Bispectral Index System and airway obstruction: an observational prospective cohort analysis during third molar extractions.

Background: Sedation regimes during oral procedures frequently associated with airway obstruction. The aim of this study was to define the association of Bispectral Index (BIS) to the depth of sedation and airway obstruction events.

Methods: Forty-seven patients between 14-21 years old, who were candidates for 3rd molar teeth extraction, were enrolled in this study. Patients received a total of 4 mg midazolam, 100 microgram fentanyl followed by titrated incremental propofol in 10 mg. The Richmond Agitation Sedation Score (RASS) was used to assess the depth of sedation. Each patient was attached to BIS monitor, while clinicians were not involved in the data collection process. Apnea, airway obstruction, O2 saturation, timing and interventions for controlling the situation were recorded. All data was synchronized with BIS data monitoring.

Results: The results show that 97.5% of cases were ASA 1 and 2, with average age of 17.3 years (±1.4) and a median BMI of 26.1. By using linear regression, for every unit decrease of median RASS (less than zero), there was 1.78 decrease in mean BIS Score (P=0.045, 95% CI: 0.08-3.47). The mean BIS Index (over 1 minute) with airway obstruction was 64 (±10.2), which was significantly lower than the BIS during non-airway obstruction (77±11.6), (P<0.001). By using logistic regression analysis, for every on unit increase in BIS Index, there is 24% decrease in odds in having airway obstruction (P=0.0009, 95% CI: 0.65-8.94).

Conclusions: This study demonstrates that the BIS could potentially be a valid continuous monitoring method to avoid airway obstruction during sedation for patients undergoing dental surgery.