ABSTRACT
Objective To study the effect of ephedrine on middle latency auditory-evoked potentials (MLAEP) during light general anesthesia , and evaluate the influence of ephedrine on anesthesia level. Methods 10 patients (ASAⅠ-Ⅱ) undergoing elective upper abdominal operations were concerned. Anesthesia: epidural anesthesia in combination with light general anesthesia with N 2O-O 2 . After success of epidural anesthesia and tracheal intubation , when anesthesia was smooth , before operation 0.1% ephedrine(0.15 mg/kg) was injected intravenously. These data HR, SBP, DBP, MBP were measured continuously before injection, 3 min after injection, 10 min after injection; the latentcies Nb and P1 of MLAEP were measured and rescorded. Results HR?SBP?DBP?MBP increased significantly 3 min after injection, 10 min after injection compared with these data before injection (P