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“Objective: To assess the suitability of contralateral suppression (CS) of distortion product otoacoustic emissions (DPOAEs) for measurement of activity of the medial olivocochlear (MOC) efferents.
Background: The MOC efferent system has been shown to be involved in sound discrimination, selective attention to tones, sound localization, and protection of the cochlea against noise. A great variety of paradigms for measurement of MOC activity by CS of OAE (MOC reflex [MOCR]), has been described. An issue of
this approach is the dependence of the CS values on stimulus parameters, especially when DPOAE are used.
Methods: Four different measurement paradigms, which used different combinations of stimulus frequencies and primary tone levels, were applied in 16 human subjects.
Results: Mean absolute values
of CS were in the range of 1.2 to 2.6 dB. The use of different stimulus parameters produced not only MOCR values of different size-which S3I-201 datasheet was expected-but, in many cases, also different relative classifications of the subjects according to their MOCR strength.
Conclusion: The suppression effects on DPOAE demonstrated in this study reflect MOC activity. However, the new conclusion from our data is that CS of DPOAE measurements, as they were used in this study, may not allow for a consistent quantitative classification of human subjects according to their MOCR strength. This finding concerns interpretation GNS-1480 concentration of previous studies using CS of DPOAE and analogous future studies. One future approach may lie in the separation of the DPOAE components to distinguish interference phenomena, which complicate interpretation of CS values.”
“The aim of our study was to compare the effects of fentanyl, remifentanil, and dexmedetomidine on neuromuscular blockade under sevoflurane anesthesia.
Eighty-four patients were randomized to fentanyl, remifentanil, and dexmedetomidine groups. In the fentanyl group, fentanyl 1.5 mu g/kg Sapitinib concentration was given before induction of anesthesia, and additional 50-mu g boluses were
administered. In the remifentanil group, the initial dose of remifentanil 1 mu g/kg was infused in 10 min before induction and 0.1 mu g/kg/min infusion was continued during anesthesia. In the dexmedetomidine group, the initial dose of dexmedetomidine 1 mu g/kg was infused in 10 min before induction and 1 mu g/kg/h infusion was continued during anesthesia. Heart rate, blood pressure, SpO(2), EtCO2, and TOF (train-of-four) values of all patients were monitored during anesthesia. Times to reach TOF 0 and TOF 25% and intubation quality were recorded.
T (0) times and quality of intubation were found to be similar among the groups. T (25) time was found to be significantly longer in the dexmedetomidine group than in the fentanyl and remifentanil groups.
Dexmedetomidine infusion increased the duration of neuromuscular blockade with vecuronium during general anesthesia.