Comparison of anesthetic agents on otoacoustic emissions in children: propofol vs ketamine.

BACKGROUND: Otoacoustic emission (OAE) tests are important evaluation tools for diagnosis of peripheral auditory pathology. Sedation or general anesthesia may be required for the performance of the OAE tests. The aim of this retrospective study was to compare the effects of anesthetic agents, propofol and ketamine, on OAEs in children. METHODS: Fifty healthy children who underwent tonsillectomy and/or adenoidectomy under general anesthesia were included in this study. Three anesthesia induction protocols were defined for this study and the anesthesiologist applied his or her own choice. Transient evoked otoacoustic emissions (TEOAEs) and distortion-product otoacoustic emissions (DPOAEs) were automatically recorded in both ears of each patient prior to anesthetic (predrug) and following the loss of consciousness 5 min later (postdrug) by an audiologist blinded to the method of anesthesia. Acceptable TEOAEs were defined as signal noise ratio (S/N) of above 3 dB SPL (decibel sound pressure level) and DPOAEs of 6 dB SPL or above. Between-group and within-group comparisons and correlations were performed for statistical analysis. RESULTS: Retrospective review of the anesthesia charts from 44 cases that completed the study showed that propofol, ketamine, and sevoflurane induction protocols were used in 21, 18, and 5 cases, respectively. Measurements of 36 ears in the propofol group and 34 ears in the ketamine group were included in the final analysis. Postdrug TEOAE and DPOAE amplitudes were significantly lower than predrug amplitudes except at 8 kHz in the ketamine group. There was no significant statistical difference in postdrug DPOAE measurements between propofol and ketamine groups but a significant difference was observed at 2 and 3 kHz of postdrug TEOAE measurements. TEOAE measurements were below 3 dB in 8 of 34 ears after ketamine and in 1 of 36 ears after propofol administration. There was a significant difference between the groups with respect to the incidence of successful measurements of TEOAEs. The DPOAE measurements were affected less by these drugs. CONCLUSION: DPOAE measurements were reduced similarly by propofol and ketamine anesthesia. Lower false outcome ratio in TEOAE measurements made propofol a better option than ketamine.

Protective role of intratympanic nigella sativa oil against gentamicin induced hearing loss.

OBJECTIVE: Aminoglycosides, used to combat with life-threatening infections, have a substantial risk of hearing loss. Nigella sativa is an annual herbaceous plant and used for treatment of many diseases for ages. We aimed to investigate the protective role of intratympanic nigella sativa oil against gentamicin induced hearing loss in an animal model. METHODS AND MATERIALS: Twenty eight guinea pigs were randomly divided into four groups: i-control, ii- Intratympanic nigella sativa oil (IT-NSO), iii- Intraperitoneal gentamicin (IP-G) and iv- Intraperitoneal gentamicin and intratympanic nigella sativa oil (IP-G + IT-NSO). Preoperative and postoperative hearing thresholds were determined with auditory brainstem response with click and 8 kHz tone-burst stimuli. Histological analysis of the cochlea specimens were performed under light microscope. Semiquantitative grading of the histological findings was carried out and compared between the groups. RESULTS: Highest posttreatment hearing thresholds were detected in IP-G group. Posttreatment mean hearing threshold of the IP-G group with click stimulus was significantly higher than the IP-G + IT-NSO group (p = 0.004). whereas the difference was not significant with 8 kHz tone-burst stimulus (p = 0.137). Both IP-G and IP-G + IT-NSO groups had significantly higher hearing thresholds compared to control and IT-NSO groups (p > 0.05). Histological examination of the control and IT-NSO groups demonstrated normal appearance of cochlear nerve, stria vascularis and organ of Corti. IP-G group showed the most severe histological alterations including hydropic and vacuolar degenerations, hair cell damage and deformation of the basilar mambrane. Histological evidence of damage was significantly reduced in IP-G + IT-NSO group compared to IP-G group. CONCLUSION: Addition of intratympanic NSO to systemic gentamicin was demonstrated to have beneficial effects in hearing thresholds which was supported by histological findings.

Wideband Tympanometry Normative Data for Turkish Young Adult Population.

OBJECTIVE: The aim of this study was to obtain norm values for a young adult Turkish group and to investigate the differences between female and male subjects in terms of wideband tympanometry. MATERIALS AND METHODS: One hundred ten young adult volunteers (mean±SD: 21.1±1.9 years) participated in this study. The measurements of wideband tympanometry were performed at octave frequencies between 226 Hz and 8000 Hz using Titan version 3.1. The stimulus level was set at 100 dB peSPL. RESULTS: A cross-sectional study design was used. In total, 218 ears were tested. A significant relationship was found between gender and absorbance values for the frequency band from 3100 Hz to 6900 Hz. The difference between the middle ear resonance frequency and ear canal volume (ECV) of the male and female subjects was also found to be significant. The difference in ECV may result from the difference in body size between the male and female subjects because there was a significant relationship among ECV and the height and weight. CONCLUSION: According to these results, it can be concluded that using separate norms for males and females may increase test specificity and sensitivity for the diagnosis of disorders, such as ossicular discontinuity and tympanic membrane perforations, affecting the high-frequency region.