Association between the Clinically Assessed Blink Reflex and Bispectral Index during Propofol Induction of Anesthesia at Dr. Sardjito General Hospital, Yogyakarta

Abstract

Background: Assessment of anesthetic depth during induction is essential to ensure patient safety and to prevent intraoperative awareness. The Bispectral Index (BIS) is a widely used objective monitor derived from electroencephalographic activity; however, its use may be limited by cost and equipment availability. The clinically assessed blink reflex is a simple bedside sign that may serve as a practical indicator during anesthetic induction.
Objective: To determine the association between the clinically assessed blink reflex and BIS values during propofol induction of anesthesia.
Methods: This was a prospective observational analytic study involving 59 adult patients aged 18–65 years with American Society of Anesthesiologists (ASA) physical status I–II who underwent elective surgery under general anesthesia at Dr. Sardjito General Hospital. All patients received propofol 1.5 mg/kg for induction. The clinically assessed blink reflex and BIS were evaluated at baseline and at 15, 30, and 60 seconds after induction. In this study, the blink reflex was defined as a bedside elicited eyelid-closure response recorded as present or absent. Data were analyzed using the chi-square test or Fisher’s exact test, followed by multivariable analysis.
Results: Before induction, all participants exhibited an intact blink reflex on bedside examination. At 15 seconds after induction, the blink reflex was still present in 36 patients (61.0%), decreasing to 8 patients (13.6%) at 30 seconds, and disappearing in all patients at 60 seconds.