Effect of propofol at different effect-site concentrations on approximate entropy of transient evoked otoacoustic emission signals in adults / 南方医科大学学报

ABSTRACT

<p><b>OBJECTIVE</b>To study the effect of propofol at different effect-site concentrations on approximate entropy (ApEn) of transient evoked otoacoustic emission (TEOAE) signals in adults and investigate the possibility of using ApEn for monitoring anesthesia depth.</p><p><b>METHODS</b>Fifteen ASA class I or II patients (aged 18-49 years with normal hearing) undergoing elective surgery under general anesthesia were enrolled in this study. Anesthesia was maintained with target-controlled infusion of propofol. With the effect-site concentrations of 1, 2, 3 and 4 microg/ml, TEOAE signals were monitored and recorded before and after anesthesia. ApEn of TEOAE in 4 frequency ranges (0-2, 1-3, 2.5-4.5, and 4-6 kHz) were calculated using MATLAB software.</p><p><b>RESULTS</b>The ApEn of TEOAE in different frequency ranges showed no significant differences at the same effect-site concentration of propofol, or at different effect-site concentrations in the same frequency range (P>0.05).</p><p><b>CONCLUSION</b>Anesthesia with propofol at different effect-site concentrations does not obviously affect ApEn of TEOAE signals in adults, and ApEn can not be used as the indicator for evaluating the depth of anesthesia.</p>