The relationship between bi-spectral index and VOTE score in evaluation of drug-induced sleep endoscopy: A systematic meta-analysis

OBJECTIVE: The aim of this study was to investigate both the presence and severity of collapse in anatomical regions defined by the VOTE score (velum, orofarinx, tongue, and epiglottis), during drug induced sleep endoscopy (DISE) in patients diagnosed with obstructive sleep apnea, based on the bi-spectral index (BIS) sedation level. METHODS: In order to conduct a meta-analysis of articles examining the relationship between the VOTE score and BIS sedation level in determining the presence and severity of upper airway collapse during DISE, a literature review was performed. RESULTS: As a result of the search made in the specified databases, a total of 1864 articles were reached. Five articles included in this review that had sufficient statistical data to be included in the meta-analysis were found. A statistically significant correlation was found between the BIS sedation level and the areas of obstruction in the VOTE score. The strongest association is at the epiglottis level, followed by the velum, oropharynx, and tongue, respectively (CC: 0.639, CC: 0.53, CC: 0.49, and CC: 0.346, P < .001). In the subgroup analysis of publications with BIS sedation levels in the range of 60 to 65, the distribution in the epiglottis region was heterogeneous, and it was found to be statistically significant according to the random effect model (P < .001). The distribution in the tongue was homogeneous, and it was found to be statistically significant according to the fixed effect model (P < .001). When the publications in which the BIS sedation level is in the range of 65 to 75 are examined according to the areas of obstruction; the distribution in 4 anatomical regions was homogeneous and statistically significant according to the fixed effect model (P < .001). CONCLUSION: It was found that BIS sedation levels during DISE application in obstructive sleep apnea patients were associated with obstruction of the anatomical regions of the upper airway. The strongest association was found at the epiglottis level, followed by the velum, oropharynx, and tongue, respectively. It is helpful to monitor the sedation level with BIS in order to better define the collapsed areas during DISE application. However, more studies are needed to better understand the relationship between BIS sedation values and sleep stages.