ABSTRACT
To investigate the effect of acoustic reflex decay sounds on the amplitude of distortion product otoacoustic emission in adults with normal hearing threshold level. A total of 20 subjects of both sexes aged between 18 and 25 years [mean: 22 years] were examined. Inclusion criteria were normal otoscopic and tympanoscopic findings, and pure tone thresholds of <20dB for 500-2000 Hz frequency range. One ear of the subjects, i.e. 20 ears, underwent DPOAE recording followed by acoustic reflex and reflex decay testing for 500-2000Hz at the audiology department at King Hussein Medical Centre between September 2013 and August 2014. The study was approved by the Royal Medical Services ethical committee. All subjects were not paid or otherwise reimbursed. Significant difference in the mean distortion product otoacoustic emission amplitudes were noticed before and after acoustic reflex decay testing. The maximum DPOAE reduction of approximately 12 dB in the frequency range 750-2000 Hz after exposure to continuous steady high sound for 10 seconds. The distortion otoacoustic emission strength went back to base line before exposure after 30 minutes. There is a strong correlation between high continuous intensity sound and the reduction in the distortion product otoacoustic emission amplitude. The function of the outer hair cells [OHCs] is impaired after exposure to high intensity. Distortion product otoacoustic emissions [DPOAEs] are useful in examination of noise-induced level shifts, reflex decay high intensity sounds may result in temporary reduction in the distortion product otoacoustic emission strength. Further investigation to be carried out on a group of hearing impaired patients to quantify the effect of the acoustic reflex decay on the distortion product otoacoustic emission amplitude whether its the OAE amplitude reduction is temporary or permanent
Subject(s)
Adult , Female , Humans , Male , Otoacoustic Emissions, Spontaneous , Acoustic Stimulation , HearingABSTRACT
To compare the effect of gastric emptying with an orogastric tube and the effect of a single dose of dexamethasone on the incidence of postoperative vomiting in children undergoing tonsillectomy. Two hundred and ten patients of both genders, aged 1.5-14 years, who were scheduled to undergo tonsillectomy with or without adenoidectomy were studied prospectively. Patients were randomized into three groups. Group I included patients who underwent gastric aspiration with an orogastric tube prior to extubation following surgery [n = 70]. Group II included patients who received dexamethasone 0.5 mg/kg intravenously [maximum dose 8 mg] after the induction of anesthesia and before surgery [n = 70]. Group III included patients who neither received dexamethasone nor underwent gastric aspiration [n = 70]. Data on the number of episodes of vomiting, total volume of emesis, administration of rescue prophylactic antiemetics were recorded. The incidence of early postoperative vomiting [before discharge from recovery room] was not significantly different between the three groups. The incidence of vomiting during stay on the ward [late vomiting] was more frequent in group I and III. The mean number of episodes of vomiting in the three groups was 2.42.2 and 2.3 respectively. The mean volume of emesis for the patients who experienced postoperative vomiting was similar in the three groups [183 ml, 176 ml and 180 ml respectively]. Prophylactic antiemetic rescues were required in 13% of group I, 4% in group II and 10% in group III. The time to the first oral intake and duration of intravenous hydration was significantly shorter in the dexamethasone group than in the other two groups. Prophylactic intra operative single dose of dexamethasone decreases the incidence of postoperative vomiting, and accelerates the return to normal diet in children undergoing tonsillectomy. Aspiration of gastric contents with an orogastric tube does not decrease postoperative vomiting, mean number of vomiting episodes and the volume of emesis. Routine use of orogastric tube placement for gastric aspiration following pediatric tonsillectomy is not advisable