Change of Stapedial Reflex Threshold according to the Depth of Intravenous Propofol Anesthesia / 대한이비인후과학회지

ABSTRACT

BACKGROUND AND OBJECTIVES: Stapedial reflex (SR) threshold is of considerable diagnostic significance in the evaluation of audiological function, especially under sedation or general anesthesia since anesthetic drugs often act on neurotransmitters or neuromodulators. The aim of this study was to evaluate the changes in the SR threshold according to the depth of anesthesia. SUBJECTS AND METHOD: Sixty patients with normal hearing who were scheduled for operation under general anesthesia were included in this study. Anesthetic agent used was propofol and the depth of anesthesia was monitored by the bispectral index (BIS). SR was measured five times according to depth of anesthesia. RESULTS: Both ipsilateral and contralateral SR thresholds were increased according to the depth of anesthesia using propofol. In particular, ipsilateral SR showed no response at BIS 60 and contralateral SR at BIS 40. However, there were no significant differences between age groups and gender. CONCLUSION: Propofol significantly increased both ipsilateral and contralateral SR threshold according to depth of anesthesia. When it is necessary to measure SR under general anesthesia, we should consider the effect on SR threshold according to the depth of anesthesia.