Changes Of Auditory Evoked Potential Index During Endotracheal Intubation And The Influence Of Surface Anesthesia On It

ObjectiveTo observe the changes of Auditory evoked potential index(AEPI) during endotracheal intubation and whether intravenous administration of lidocaine and tetracaine(dicaine) surface anesthesia could affect this change.Methods36 patinets of ASA physical status and Mallampati intubation status I or II scheduled for general anesthesia were included in this study. These patients were randomly allocated into one of three groups: Contrast Group(Group C), Lidocaine Group(Group L) and Tetracaine Group(Group T). The patients in Group L and Group T received intravenous Jidocaine(l%) and tetracaine(l%) surface anesthesia before endotracheal intubation respectively. AEPI, Blood Pressure, Heart Rate and the time between vecuronium injection and endotracheal intubation were recorded and compared between groups.ResultsAEPI rised significantly after endotracheal intubation, the raise of AEPI of Group T was bigger than those of Group C and L; the raises of blood pressure and heart rate after endotracheal intubation were significantly lower than the other two groups; there were similar blood pressure and heart rate changes in Group C and T after intubation.ConclusionAEPI is more sensitive than rheodynamics indeices in terms of detecting response to tracheal intubation, neither intravenous lidocaine or tetracaine surface anesthesia can inhibit its change during intubation; intravenous administration of lidocaine can significantly attenuate the cardiovascular response; surface anesthesia immediately before tracheal intubation can not depress the cardiovascular response, but can enchance the raise of AAI result from endotracheal intubation.