Otoacoustic emissions (OAEs) are non-invasive, easy to apply and objective test methods which are widely used to determine the presence of hearing in audiology clinics. Under some circumstances and children, the study should be applied under general anaesthesia. The aim of this study was to find out the influence of propofol (P) and ketamine (K) on OAE measurements. .

Methods: Thirty- healthy children who will underwent adenoidectomy and tonsillectomy will be included in this study after Institutional ethics committee approval and informed consent of parents. Children will be evaluated one day before surgery by tympanometry. Psychologically prepared children will be admitted to the operating room. Following EMLA (Eutectic Mixture of Local Anesthetics ) cream application IV line will be inserted. ECG and non-invasive blood pressure will be monitored. Transient evoked otoacoustic emissions (TEOAEs) and distortion product otoacoustic emissions (DPOAEs) will measured in both ears of each patient (n=20 ears) prior to P or K administration( Pre-P and Pre-K). Propofol will be given 2mg/kg or ketamine 2mg/kg intravenously and 40% O2 in air will be given by mask ventilation. Five minutes later TEOAE and DPOAE measurements will be repeated (Post-P and Post-K). After this measurement the routine general anaesthesia and surgical protocol will be commenced. Heart rate, blood pressures TEOAE and DPOAE measurements will be compared at pre and post stages by paired Student's t- test.

Inclusion Criteria:

children ages 4-15 years ASA ( American Society of Anesthesiologists) I-II Tonsillectomy and/or adenoidectomy Normal ear hearing tests

Exclusion Criteria:

Abnormal hearing tests Abnormal laboratory (Electrolyte imbalance, anemia, polycythemia, thrombocytopenia, leucopenia , leucocytosis) Congenital abnormalities and previous systemic diseases Hypo or hyperthermia Ear operations Long term fasting, dehydration or over hydration Upper respiratory disease, acute or chronic otitis,

children ages 4-15 years ASA I-II Tonsillectomy and/or adenoidectomy Normal ear hearing tests