Search

Objectives. Balloon dilation of the Eustachian tube (BDET) is widely recognized as a minimally invasive treatment for obstructive Eustachian tube dysfunction (ETD). We employed a Delphi consensus methodology to develop recommendations for the clinical management of BDET in cases of obstructive ETD. Methods. A Delphi panel consisting of 26 expert physicians specializing in otology participated in two rounds of anonymous, iterative questionnaires. Consensus was defined as agreement from ≥70% of the panelists on a recommendation, while disagreement was defined as

Gradenigo's syndrome, a rare but serious complication of otitis media, encompasses a triad of symptoms including otalgia, facial palsy, and abducens nerve palsy, pointing to the involvement of the petrous apex. This case report presents an 11-year-old boy with an atypical manifestation of Gradenigo's syndrome, characterized by the absence of classic features such as abducens nerve palsy and purulent otorrhea. MRI findings were significant for petrous apicitis extending to Meckel's cave and the cavernous sinus, along with abscess formation and clivus osteomyelitis. The report highlights the critical role of advanced neuroimaging, particularly MRI, in the diagnosis and management of this condition. It underscores the importance of recognizing atypical presentations of Gradenigo's syndrome and the effectiveness of imaging-guided conservative treatment strategies in pediatric otological cases.

Abstract Background We aimed to identify the ideal chest compression site for cardiopulmonary resuscitation (CPR) in patients with a single ventricle with dextrocardia corrected by Fontan surgery. Methods The most recent stored chest computed tomography images of all patients with a single ventricle who underwent Fontan surgery were retrospectively analysed. We reported that the ideal chest compression site is the largest part of the compressed single ventricle. To identify the ideal chest compression site, we measured the distance from the midline of the sternum to the point of the maximum sagittal area of the single ventricle as a deviation and calculated the area fraction of the compressed structures. Results 58 patients (67.2% male) were analysed. The mean right deviation from the midline of the sternum to the ideal compression site was similar to the mean sternum width (32.85 ± 15.61 vs. 31.05 ± 6.75 mm). When chest compression was performed at the ideal site, the area fraction of the single ventricle significantly increased by 7%, which was greater than that of conventional compression (0.15 ± 0.10 vs. 0.22 ± 0.11, P

Purpose This study was performed to identify risk factors associated with post-tonsillectomy hemorrhage (PTH)-related hospitalization in pediatric patients visiting an emergency department (ED). Methods We retrospectively reviewed the medical records of patients who underwent tonsillectomy at a single children’s hospital ED from January 2009 through December 2020. Data were collected on patient demographics, chief complaints, surgical methods, postoperative days, initial vital signs, and laboratory findings. The study population was divided into hospitalized and discharged groups. Results Among a total of 2,716 patients reviewed, 67 met the inclusion criteria. The hospitalized group showed a lower median systolic blood pressure (108.0 [interquartile range, 82.0-134.0] vs. 118.5 [89.8-147.2] mmHg; P = 0.021) and a faster median respiratory rate (23.0 [18.0-28.0] vs. 20.0 [17.0-23.0] breaths/minute; P = 0.019), compared with the discharged group. Multivariable logistic regression identified systolic blood pressure under 100 mmHg (odds ratio, 5.21; 95% confidence interval, 1.17-37.60) and respiratory rate over 24 breaths/minute (7.31; 1.07-145.79) as the factors associated with PTH-related hospitalization. Conclusion When pediatric patients visit EDs for PTH, close monitoring or hospitalization may be needed in those with low systolic blood pressure or rapid respiratory rate.

Abstract Background Abdominal pain, which is a common cause of children presenting to the paediatric emergency department (PED), is often evaluated by ultrasonography (US). However, uncertainty in US reports may necessitate additional imaging. Objective In this study, we evaluated factors contributing to uncertainty in paediatric abdominal US reports in the PED. Materials and methods This retrospective cohort study included children younger than 18 years of age who underwent abdominal US in the PED of the study hospital between January 2017 and December 2019. After exclusion, the researchers manually reviewed and classified all US reports as ‘certain’ or ‘uncertain’. Univariate and multivariate logistic regression analyses were performed to identify the factors contributing to uncertain reports. Results In total, 1006 patients were included in the final analysis., 796 patients were tagged as having certain reports, and 210 as having uncertain reports. Children with uncertain reports had a significantly higher rate of undergoing an additional computed tomography (CT) scan (31.0% vs. 2.5%, p

With the age of exposure to illegal substances decreasing and abuse of drugs such as methamphetamine increasing, substance abuse is no longer limited to adults. We report a Korean case of a 17-year-old girl with acute methamphetamine poisoning. The girl visited the emergency department for vomiting and loss of consciousness, with needle marks found on both arms. QT prolongation was confirmed on the initial electrocardiogram, so that we suspected drug addiction and proceeded with toxicologic tests. A lethal dose of methamphetamine was confirmed. We discontinued QT prolonging drugs, and closely monitored the girl in the pediatric emergency intensive care unit until the QT prolongation was resolved. This case highlights the recognition of pediatric methamphetamine poisoning in emergency departments.

Noise exposure can destroy the synaptic connections between hair cells and auditory nerve fibers without damaging the hair cells, and this synaptic loss could contribute to difficult hearing in noisy environments. In this study, we investigated whether delivering lithium chloride to the round-window can regenerate synaptic loss of cochlea after acoustic overexposure. Our rat animal model of noise-induced cochlear synaptopathy caused about 50% loss of synapses in the cochlear basal region without damaging hair cells. We locally delivered a single treatment of poloxamer 407 (vehicle) containing lithium chloride (either 1 mM or 2 mM) to the round-window niche 24 hours after noise exposure. Controls included animals exposed to noise who received only the vehicle. Auditory brainstem responses were measured 3 days, 1 week, and 2 weeks post-exposure treatment, and cochleas were harvested 1 week and 2 weeks post-exposure treatment for histological analysis. As documented by confocal microscopy of immunostained ribbon synapses, local delivery of 2 mM lithium chloride produced synaptic regeneration coupled with corresponding functional recovery, as seen in the suprathreshold amplitude of auditory brainstem response wave 1. Western blot analyses revealed that 2 mM lithium chloride suppressed N-methyl-D-aspartate (NMDA) receptor expression 7 days after noise-exposure. Thus, round-window delivery of lithium chloride using poloxamer 407 reduces cochlear synaptic loss after acoustic overexposure by inhibiting NMDA receptor activity in rat model.

Purpose Genital injury is a common pediatric injury. Given the lack of nationwide data, the authors aimed to show age group-related epidemiologic features of genital injury in Korea. Methods We reviewed the data from 2011-2016 Emergency Department-based Injury In-depth Surveillance registry, which involves 23 emergency departments in Korea. From the dataset, we included children (< 18 years) with the International Classification of Diseases, 10th Revision codes related to genital injury as the final diagnosis with excluding those with other codes or combined injuries. Age groups were defined as follows; infants (< 1 year), toddlers (1-3), preschoolers (4-6), schoolers (7-12), and adolescents (13-17). The clinical features and outcomes were analyzed. Results A total of 3,030 children were included with the median age of 6 years (interquartile range, 4-10) and the proportion of girls of 53.0%. Only 144 children (4.8%) were transported by the emergency medical service providers. The most common mechanism and place were blunt injury (1,826 [60.3%]) and home (1,535 [50.7%]), respectively. Of the codes, “Contusion of external genital organs (S30.2)” was most common (1,574 [51.9%]). As for outcomes, 2,770 children (91.4%) were discharged, 252 (8.3%) were hospitalized (intensive care units, 1 child [0.03%]), and 108 (3.6%) underwent surgery. Severe injury occurred in 111 children (3.7%) without a mortality. With increasing age in the age groups, non-accidental injury, school and sports-related injuries, hospitalization, and surgery (All Ps < 0.001). Conclusion Genital injury may occur at evening, in spring and summer, at home, and in the form of accidental or blunt injury. Most children are discharged. Contrary to these general features, older children tend to undergo more frequently non-accidental injury, school and sports-related injuries, hospitalization, and surgery. Thus, we need age-specific strategies for injury prevention.

Purpose In Korea, the Broselow tape (BT) is widely used to estimate weight in resuscitation. Validation of BT in Korean children is essential because the tool was developed based on children’s weight and height in the United States. The validation was previously performed in a small-scale dataset. The authors aimed to validate BT using the 2005 Korean nationwide anthropometric survey data. Methods From the population used for the survey, we sampled children aged 0-12 years. The weights estimated by BT were compared with measured weights of the children using Bland-Altman analysis with results recorded as percentage differences. We measured the accuracy of BT, defined as within a 10% error of the measured weight, and the concordance of the color-coded zones derived from the estimated and measured weights. The accuracy and concordance were further assessed according to the age groups and body mass index-for-age Z-score (< -2, underweight; > 2, overweight or obese). Results A total of 108,128 children were enrolled. The mean age was 55.2 ± 37.5 months. The bias was –5.4% (P < 0.001), and the limits of agreement were –28.3% and 17.6%, respectively. The accuracy and concordance of BT were 64.4% and 67.2%, respectively. Differences of no more than 1 color-coded zone between estimated and measured weights accounted for 89.8% and 84.1% of the under- and overweight (or obese) children, respectively. Conclusion BT accurately estimates weight in approximately two-thirds of Korean children. In addition, adjustment of 1 color-coded zone may be considered in children with extreme weight.

Objective Urinary tract infection (UTI) is a significant issue in young febrile patients due to potential long-term complications. Early detection of UTI is crucial in pediatric emergency departments (PEDs). We developed a tool to predict UTIs in children. Methods Clinical data of patients

Abstract Several studies have shown how different cell lines can influence the differentiation of stem cells through co-culture systems. The House Ear Institute-Organ of Corti 1 (HEI-OC1) is considered an important cell line for in vitro auditory research. However, it is unknown if HEI-OC1 cells can promote the differentiation of embryonic stem cells (ESCs). In this study, we investigated whether co-culture of ESCs with HEI-OC1 cells promotes differentiation. To this end, we developed a co-culture system of mouse ESCs with HEI-OC1 cells. Dissociated or embryonic bodies (EBs) of ESCs were introduced to a conditioned and inactivated confluent layer of HEI-OC1 cells for 14 days. The dissociated ESCs coalesced into an EB-like form that was smaller than the co-cultured EBs. Contact co-culture generated cells expressing several otic progenitor markers as well as hair cell specific markers. ESCs and EBs were also cultured in non-contact setup but using conditioned medium from HEI-OC1 cells, indicating that soluble factors alone could have a similar effect. The ESCs did not form into aggregates but were still Myo7a-positive, while the EBs degenerated. However, in the fully differentiated EBs, evidence to prove mature differentiation of inner ear hair cell was still rudimentary. Nevertheless, these results suggest that cellular interactions between ESCs and HEI-OC1 cells may both stimulate ESC differentiation.

Objectives. The relationship of estrogen (the primary female sex hormone) with hearing function has been studied in both humans and animals. However, whether estrogen levels affect hearing remains uncertain. Therefore, in this study, we investigated changes in the vulnerability of hearing to acoustic overexposure in ovariectomized female rats. Methods. Eighteen 8-week-old female Sprague-Dawley rats were separated into four groups as follows: sham ovariectomy (OP), OP only, and OP treated with low (10 µg/kg) or high doses (100 µg/kg) of estrogen. Rats in the estrogen replacement groups were given two intraperitoneal injections. Hearing thresholds were measured before noise exposure, and at 1 day and 2 weeks after exposure. Results. The hearing thresholds of the sham OP and OP-only groups were not significantly different. However, both estrogen groups showed a lower threshold shift than the OP-only group. Histological immunostaining analyses showed that hair cell loss in the 32 kHz region was more severe in the sham OP group than in the OP-only group. Furthermore, there was little or no hair cell loss in either estrogen replacement group and significantly more hair cell loss in the OP-only group. Conclusion. These results suggest that estrogen replacement may reduce the vulnerability of hearing to noise exposure in menopausal women.

Abstract Background Prostaglandin is one of the key metabolites for inflammation-related carcinogenesis. Despite the microRNA-155 is implicated in various types of cancers, it’s function in prostaglandin metabolism is largely unknown. Methods A targeted profiling of eicosanoids including prostaglandin, leukotriene and thromboxanes was performed in miR-155 deficient breast tumors and cancer cells. The molecular mechanism of miR-155-mediated prostaglandin reprogramming was investigated in primary and cancer cell lines, by analyzing key enzymes responsible for the prostaglandin production. Results We found miR-155-deficient breast tumors, plasma of tumor-bearing mouse and cancer cells show altered prostaglandin level, especially for the prostaglandin E2 (PGE2) and prostaglandin D2 (PGD2). Subsequent analysis in primary cancer cells, 20 triple-negative breast cancer (TNBC) specimens and breast cancer cell lines with miR-155 knockdown consistently showed a positive correlation between miR-155 level and PGE2/PGD2 ratio. Mechanistically, we reveal the miR-155 reprograms the prostaglandin metabolism by up-regulating PGE2-producing enzymes PTGES/PTGES2 while down-regulating PGD2-producing enzyme PTGDS. Further, we show the up-regulation of PTGES2 is driven by miR-155-cMYC axis, whereas PTGES is transactivated by miR-155-KLF4. Thus, miR-155 hires dual-regulatory mode for the metabolic enzyme expression to reprogram the PGE2/PGD2 balance. Lastly, we show the miR-155-driven cellular proliferation is restored by the siRNA of PTGES1/2, of which expression also significantly correlates with breast cancer patients’ survival. Conclusions Considering clinical trials targeting PGE2 production largely have focused on the inhibition of Cox1 or Cox2 that showed cardiac toxicity, our data suggest an alternative way for suppressing PGE2 production via the inhibition of miR-155. As the antagomiR of miR-155 (MRG-106) underwent a phase-1 clinical trial, its effect should be considered and analyzed in prostaglandin metabolism in tumor.

Objective: We developed and validated a realistic simulation model for ultrasound-guided central venous catheter insertion in children that is easy to build and inexpensive and can automatically reproduce arterial and venous blood flow. Methods: The simulation model was constructed with a chicken breast, two DWP-385 water pumps, two types of tubes and a controller. An elastic rubber tourniquet and a silicone tube were connected to each water pump, which generated different continuous flows mimicking those of the pediatric internal carotid artery and internal jugular vein, respectively. Both tubes were inserted into a piece of chicken breast and connected to the controller. Then, we provided a simulation program of ultrasound-guided central venous catheter insertion using our novel model to resident emergency medicine physicians. We also collected data on their knowledge and confidence levels regarding the procedure before and after the simulation via questionnaires utilizing a 5-point Likert scale. Results: The flow patterns of the artery and vein were well demonstrated with our model. A total of 11 resident physicians were enrolled. The knowledge and confidence regarding the discrimination of arteries and veins were significantly improved after training with our simulation model (p-value < 0.01). The subjective similarity and usefulness of our model also scored high on the questionnaire (median: 4; interquartile range in both categories: 4–5). Conclusion: Our novel simulation model is useful and realistic for ultrasound-guided central venous catheter insertion training. Clinical impact: This controlled motor system can be applied to many simulation models of artery and vein circulation.

Objective Trampoline-related injuries have increased in South Korea. However, little research has been conducted on this topic. This study aimed to show the characteristics of pediatric trampoline-related injuries in South Korea and to investigate the factors associated with admission. Methods A retrospective, cross-sectional study was conducted using data from South Korea’s Emergency Department-based Injury In-depth Surveillance registry for dates between January 2011 and December 2016. All patients under 18 years of age with trampoline-related injuries were included. We divided the patients into two groups based on whether they were admitted or discharged. Odds ratios with 95% confidence intervals were calculated to evaluate the factors associated with hospital admission for pediatric trampoline-related injuries. Results A total of 2,745 patients were enrolled and the incidence increased over time (P for trend

In pediatric patients, central venous catheterization (CVC) is necessary for administration of fluids, drugs, high concentration electrolytes, vasopressors or inotropic drugs, transfusion, intravenous nutrition, and dialysis. Using an anatomical landmark for the CVC insertion may have a low success rate in children due to the positional variation between the deep vein and the landmarks, the small size of body and blood vessels, low insertion frequency, and operator skill. In order to improve the success rate, ultrasound guided CVC insertion is recommended in critically ill children. It is also expected to reduce mechanical complications, which are more common with subclavian CVC insertion. However, the association between the insertion site and the infection or thrombosis is unclear. Since thrombosis is relatively common, further studies are needed on the association between the incidence rate and insertion sites.

Photobiomodulation (PBM) stimulates different types of stem cells to migrate, proliferate, and differentiate in vitro and in vivo. However, little is known about the effects of PBM on the differentiation of embryonic stem cells (ESCs) toward the otic lineage. Only a few reports have documented the in vitro differentiation of ESCs into inner-ear hair cells (HCs) due to the complexity of HCs compared with other target cell types. In this study, we determined the optimal condition to differentiate the ESCs into the otic organoid using different culture techniques and PBM parameters. The efficiency of organoid formation within the embryoid body (EB) was dependent on the cell density of the hanging drop. PBM, using 630 nm wavelength light-emitting diodes (LEDs), further improved the differentiation of inner-ear hair cell-like cells coupled with reactive oxygen species (ROS) overexpression. Transcriptome analysis showed the factors that are responsible for the effect of PBM in the formation of otic organoids, notably, the downregulation of neural development-associated genes and the hairy and enhancer of split 5 (Hes5) gene, which inhibits the differentiation of prosensory cells to hair cells. These data enrich the current differentiation protocols for generating inner-ear hair cells.

The Pediatric Emergency Care Applied Research Network (PECARN) rule is commonly used for predicting the need for computed tomography (CT) scans in children with mild head trauma. The objective of this study was to validate the PECARN rule in Korean children presenting to the pediatric emergency department (PED) with head trauma. This study was a multicenter, retrospective, observational cohort study in two teaching PEDs in Korea between August 2015 and August 2016. In this observational study, 448 patients who visited PEDs were included in the final analysis. Risk stratification was performed with clinical decision support software based on the PECARN rule, and decisions to perform CT scans were subsequently made. Patients were followed-up by phone call between 7 days and 90 days after discharge from the PED. The sensitivity and specificity were analyzed. The sensitivity was 100% for all age groups, and no cases of clinically important traumatic brain injury (ciTBI) were identified in the very-low-risk group. CT scans were performed for 14.7% of patients in this study and for 33.8% in the original PECARN study. The PECARN rule successfully identified low-risk patients, and no cases of ciTBI were missed despite the reduced proportion of patients undergoing CT scans.

Abstract Background To determine whether photobiomodulation (PBM) rescued the disruption of Na+/Ca2+ homeostasis and mitochondrial membrane potential by ouabain; the Na, K-ATPase inhibitor. For PBM in this study, a 660 nm LED array was used at energy densities of 0.78, 1.56, 3.12, 6.24, and 9.36 J/cm2. Results HCN-2 neuronal cells treated with ouabain showed loss of cell polarity, disrupted cell morphology, and decreased cell viability, which were improved after PBM treatment. We found that ouabain-induced Na, K-ATPase inhibition promoted activation of downstream signaling through Src, Ras, and mitogen-activated protein kinase (MAPK), which were suppressed after PBM treatment. This provided evidence of Na, K-ATPase α-subunit inactivation and intracellular Ca2+ increase. In response to ouabain, we observed activation of Src and MAPK by Na, K-ATPase, decreased mitochondrial membrane potential, and Na+-dependent Ca2+ increases, which were restored by PBM treatment. Conclusions This study demonstrated that Na+/K+ imbalance could be regulated by PBM treatment in neuronal cells, and we suggest that PBM is a potential therapeutic tool for Na, K-ATPase targeted neuronal diseases.

Objective The use of computed tomography (CT) in pediatric patients has decreased since the association between radiation and cancer risk has been reported. However, in adolescent patients being treated as adult patients, there has been a high incidence of CT use in emergency departments (EDs). Thus, this study aimed to evaluate the CT use in adolescent patients with complaints of headache or abdominal pain in the general and pediatric EDs of the same hospital. Methods A retrospective chart review of patients aged 15 to 18 years, who presented with headache or abdominal pain at the general and pediatric EDs of Seoul National University Hospital from January 2010 to December 2014, was conducted. Results A total of 407 adolescent patients with complaints of headache and 980 with abdominal pain were included in this study. The adolescent patients in the general ED were more likely to undergo CT scans than those in the pediatric ED, with both patients having headache (42.4% vs. 20.5%, respectively, P

IntroductionA defect in the cochlear afferent synapse between the inner hair cells and spiral ganglion neurons, after noise exposure, without changes in the hearing threshold has been reported. Animal studies on auditory evoked potentials demonstrated changes in the auditory brainstem response (ABR) measurements of peak I amplitude and the loss of synapses, which affect the temporal resolution of complex sounds. Human studies of auditory evoked potential have reported ambiguous results regarding the relationship between peak I amplitude and noise exposure. Paired click stimuli have been used to investigate the temporal processing abilities of humans and animals. In this study, we investigated the utility of measuring auditory evoked potentials in response to paired click stimuli to assess the temporal processing function of ribbon synapses in noise-induced cochlear synaptopathy.Materials and MethodsTwenty-two Sprague Dawley rats were used in this study, and synaptopathy was induced by narrow-band noise exposure (16 kHz with 1 kHz bandwidth, 105 dB sound pressure level for 2 h). ABRs to tone and paired click stimuli were measured before and 1, 3, 7, and 14 days after noise exposure. For histological analyses, hair cells and ribbon synapses were immunostained and the synapses quantified. The relationships among ABR peak I amplitude, number of synapses, and ABR to paired click stimuli were examined.ResultsOur results showed that ABR thresholds increase 1 day after noise exposure but fully recover to baseline levels after 14 days. Further, we demonstrated test frequency-dependent decreases in peak I amplitude and the number of synapses after noise exposure. These decreases were statistically significant at frequencies of 16 and 32 kHz. However, the ABR recovery threshold to paired click stimuli increased, which represent deterioration in the ability of temporal auditory processing. Our results indicate that the ABR recovery threshold is highly correlated with ABR peak I amplitude after noise exposure. We also established a direct correlation between the ABR recovery threshold and histological findings.ConclusionThe result from this study suggests that in animal studies, the ABR to paired click stimuli along with peak I amplitude has potential as an assessment tool for hidden hearing loss.

BackgroundPoint-of-care ultrasound is one of useful diagnostic tools in emergency medicine practice and considerably depends on physician's performance. This study was performed to evaluate performance improvements and favorable attitudes through structured cardiac ultrasound program for emergency medicine residents.MethodsRetrospective observational study using the point-of-care ultrasound (PoCUS) database in one tertiary academic-teaching hospital emergency department has been conducted. Cardiac ultrasound education and rotation program has been implemented in emergency medicine residency program. Structured evaluation sheet for cardiac ultrasound and questionnaire toward PoCUS have been developed. An early-phase and a late-phase case were selected randomly for each participant. Two emergency medicine specialists with expertise in PoCUS evaluated saved images independently. We used a paired t-test to compare the performance score of each phase and the results of the questionnaire. Multivariable linear regression analysis was conducted to evaluate the association between the characteristics of participants and performance improvements.ResultsDuring the study period, a total of 1,652 bedside cardiac ultrasounds were administered. Forty-six examinations conducted by 23 emergency medicine residents were randomly selected for analysis. The performance score increased from 39.5 to 56.1 according to expert A and 45.3 to 62.9 according to expert B (p-value ConclusionsBedside cardiac ultrasound performance and attitudes toward PoCUS have been improved through structured residency program.

We assessed the feasibility and potential efficacy of a virtual reality (VR) environment using a dome screen as a distraction method in young children during intravenous (IV) placement in the pediatric emergency department. This randomized controlled pilot study enrolled children aged 2 to 6 years who underwent IV placement into either the intervention group or the control group. Children in the intervention group experienced VR using a dome screen during IV placement. The child's pain intensity was measured using the Face, Legs, Activity, Cry, and Consolability (FLACC) scale at four time points of IV placement: immediately after arrival to the blood collection room (base); immediately after the child laid down on the bed (preparation); when the tourniquet was applied (tourniquet); and the moment at which the needle penetrated the skin (venipuncture). The guardian's satisfaction and rating of the child's distress were assessed using a 5-point Likert-type questionnaire. We recruited 19 children (9 in the intervention group and 10 in the control group). Five children in the control group were excluded from the analysis because of missing video recordings (n = 3), failed first attempt at IV placement (n = 1), and the child's refusal to lie on the bed during the procedure (n = 1). No side effects of VR were reported during the study period. Although the average FLACC scale score at each time point (preparation, tourniquet, venipuncture) was lower in the intervention group than the control group, the difference was not statistically significant (2.3, interquartile range [IQR]: 2.0-3.0; vs. 3.3, IQR: 2.7-6.7, P = 0.255). There were no statistically significant differences between the groups in the guardian's satisfaction and anxiety or his/her rating of the child's pain and anxiety. The guardians and emergency medical technicians reported satisfaction with the use of VR with a dome screen and considered it a useful distraction during the procedure. VR using a dome screen is a feasible distraction method for young children during IV placement. A larger clinical trial with further development of the VR environment and study process is required to adequately evaluate the efficacy of VR using a dome screen.

Purpose To develop a clinical scoring system for children with presumed appendicitis who visit the emergency department. Methods A registry based-retrospective study was conducted in the pediatric emergency department between September 2015 and December 2016. Patients aged 4 to 17 years who had a > 1 of 5 Likert scale for possibility of appendicitis were included. Multiple logistic regressions based on Akaike information criterion were performed using variables regarding clinical features and inflammatory markers to develop the clinical scoring system. Results A total of 233 patients were included, and 93 (39.9%) had the final diagnosis of appendicitis. The final model with the lowest Akaike information criterion (171.7) consisted of 5 variables, including vomiting (1 point), absence of watery diarrhea (1 point), duration of symptoms ≤ 3 days (1 point), rebound tenderness (1 point), and white blood cell count > 10.0 × 109/L (2 points). If the clinical score was ≥ 4 of 6 points, the area under the receiver operating characteristic curve was 0.78 (95% confidence interval, 0.71-0.86) with a 78.9% sensitivity, 66.7% specificity, positive and negative predictive values of 70.0% and 76.2%, respectively, and positive and negative likelihood ratios of 2.4 and 0.3, respectively. Conclusion The 5-item clinical scoring system shows a fair performance for prediction of pediatric appendicitis. This simple tool could be applied to predict the pediatric appendicitis, and to avoid the use of potentially unnecessary computed tomography.

Objective The aim of this study was to investigate the effectiveness of a quality improvement activity for pain management in patients with extremity injury in the emergency department (ED). Methods This was a retrospective interventional study. The patient group consisted of those at least 19 years of age who visited the ED and were diagnosed with International Classification of Diseases codes S40–S99 (extremity injuries). The quality improvement activity consisted of three measures: a survey regarding activities, education, and the triage nurse’s pain assessment, including change of pain documentation on electronic medical records. The intervention was conducted from January to April in 2014 and outcome was compared between May and August in 2013 and 2014. The primary outcome was the rate of analgesic prescription, and the secondary outcome was the time to analgesic prescription. Results A total of 1,739 patients were included, and 20.3% of 867 patients in the pre-intervention period, and 28.8% of 872 patients in the post-intervention period received analgesics (P< 0.001). The prescription rate of analgesics for moderate-to-severe injuries was 36.4% in 2013 and 44.5% in 2014 (P=0.026). The time to analgesics prescription was 116.6 minutes (standard deviation 225.6) in 2013 and 64 minutes (standard deviation 75.5) in 2014 for all extremity injuries. The pain scoring increased from 1.4% to 51.6%. Conclusion ED-based quality improvement activities including education and change of pain score documentation can improve the rate of analgesic prescription and time to prescription for patients with extremity injury in the ED.

Objective Many studies have proposed reducing unnecessary use of computed tomography (CT), and ongoing studies in pediatric populations are aiming to decrease radiation dosages whenever possible. We aimed to evaluate the long-term changes in the utilization patterns of CT and ultrasound (US) in pediatric emergency departments (PEDs). Methods This retrospective study reviewed the electronic medical data of patients who underwent CT and/or US in the PED of a tertiary referral hospital from 2000 to 2014. We compared the changes in utilization patterns of brain and abdominal CT scans in pediatric patients and analyzed changes in abdominal US utilization in the PED. Results During the study period, 196,371 patients visited the PED. A total of 12,996 brain and abdominal CT scans and 12,424 abdominal US were performed in the PED. Comparison of CT use in pediatric patients before and after 2007 showed statistically decreasing trends after 2007, expressed as the coefficient values of the differences in groups. The numbers of brain and abdominal CT scans showed a significant decreasing trend in children, except for abdominal CT in adolescents. The abdominal US/CT ratio in the PED showed a statistically significant increase (2.68; 95% confidence interval, 1.87 to 3.49) except for the adolescent group (5.82; 95% confidence interval, -2.06 to 13.69). Conclusion Overall, CT use in pediatric patients has decreased since 2007. Pediatric US use has also shown a decreasing trend; however, the abdominal US/CT ratio in pediatric patients showed an increasing trend, except for adolescents.

Pancreatic cancer is characterized by late detection, frequent drug resistance, and a highly metastatic nature, leading to poor prognosis. Antibody-based immunotherapy showed limited success for pancreatic cancer, partly owing to the low delivery rate of the drug into the tumor. Herein, we describe a poly(lactic-co-glycolic acid;PLGA)-based siRNA nanoparticle targeting PD-L1 (siPD-L1@PLGA). The siPD-L1@PLGA exhibited efficient knockdown of PD-L1 in cancer cells, without affecting the cell viability up to 6 mg/mL. Further, 99.2% of PDAC cells uptake the nanoparticle and successfully blocked the IFN-gamma-mediated PD-L1 induction. Consistently, the siPD-L1@PLGA sensitized cancer cells to antigen-specific immune cells, as exemplified by Ovalbumin-targeting T cells. To evaluate its efficacy in vivo, we adopted a pancreatic PDX model in humanized mice, generated by grafting CD34+ hematopoeitic stem cells onto NSG mice. The siPD-L1@PLGA significantly suppressed pancreatic tumor growth in this model with upregulated IFN-gamma positive CD8 T cells, leading to more apoptotic tumor cells. Multiplex immunofluorescence analysis exhibited comparable immune cell compositions in control and siPD-L1@PLGA-treated tumors. However, we found higher Granzyme B expression in the siPD-L1@PLGA-treated tumors, suggesting higher activity of NK or cytotoxic T cells. Based on these results, we propose the application of siPD-L1@PLGA as an immunotherapeutic agent for pancreatic cancer.

Interfacility transport of critically ill children (transport) is a challenging component of pediatric critical care. The risk associated with the transport may be reduced by a specialized pediatric transport team, a screening tool for critically ill children, and a standardized handover between referring and referred physicians. Further research is necessary in Korea regarding the above measures for the safe and effective transport.

Objective The aim of this study was to elucidate the epidemiology of pediatric patients transported by the National 119 Rescue Services in Korea. Methods We enrolled all pediatric patients (

The cerebellopontine angle (CPA) is a triangular-shaped space that lies at the junction of the pons and cerebellum. It contains cranial nerves and the anterior inferior cerebellar artery (AICA). The anatomical shape and location of the AICA is variable within the CPA and internal auditory canal (IAC). A possible etiology of idiopathic sudden sensorineural hearing loss (ISSNHL) is ischemia of the labyrinthine artery, which is a branch of the AICA. As such, the position of the AICA within the CPA and IAC may be related to the clinical development of ISSNHL. We adopted two methods to classify the anatomic position of the AICA, then analyzed whether these classifications affected the clinical features and prognosis of ISSNHL. We retrospectively reviewed patient data from January 2015 to March 2018. Two established classification methods designed by Cahvada and Gorrie et al. were used. Pure tone threshold at four different frequencies (0.5, 1, 4, and 8 kHz), at two different time points (at initial presentation and three months after treatment), were analyzed. We compared the affected and unaffected ears, and investigated whether there were any differences in hearing recovery and symptoms between the two classification types. There was no difference in AICA types between ears with and without ISSNHL. Patients who had combined symptoms such as tinnitus and vertigo did not show a different AICA distribution compared with patients who did not. There were differences in quantitative hearing improvement between AICA types, although without statistic significance (p = 0.09–0.13). At two frequencies, 1 and 4 kHz, there were differences in Chavda types between hearing improvement and no improvement (p

In our previous study, we found that horizontal ocular deviation (OD) was significantly increased in patients with unilateral vestibular neuritis (VN). This study is aimed to compare the measurements of horizontal OD in various diseases which can present as acute vertigo in the emergency department. We retrospectively reviewed patients who visited the emergency department and underwent brain MRI due to acute vertigo. We compared them to healthy controls who underwent brain MRI for a regular health examination. Among the study participants, 149 patients who were diagnosed with benign paroxysmal positional vertigo (BPPV), unilateral Ménière's disease (MD), vestibular migraine (VM), unilateral vestibular neuritis (VN), or posterior inferior cerebellar artery (PICA) infarction were enrolled. Absolute angles of horizontal OD were larger in the definite MD (19.1 ± 12.7°), possible and probable MD (15.5 ± 11.7°), and VN (22.2 ± 11.7°) groups compared to the control group (4.3 ± 3.7°). Most VN patients (83.3%) had horizontal OD toward the direction of the lesion. About half of the MD patients (46.2%) and half of the patients with PICA infarction (50.0%) had horizontal OD toward the opposite direction of the lesion. Regarding PICA infarction, horizontal OD was observed only in patients who immediately underwent an MRI after developing the PICA territory vestibulocerebellar infarction. Although the exact mechanism of horizontal OD is unclear, this study suggests that horizontal OD reflects a static vestibular imbalance, and that the eyeball is deviated to the weaker of the two vestibular nuclei during neural resting activity. Therefore, horizontal OD could be helpful in assessing for a prior vestibular imbalance.

Intussusception is one of the most common causes of intestinal obstruction in young children. We report a retrospective, observational study of the epidemiology of intussusception in South Korea using the National Health Insurance Service-National Sample Cohort (NHIS-NSC). A cohort of newborns born between 2002 and 2008 was selected. The primary objective was to assess the incidence of intussusception in the pediatric population of Korea. The secondary objectives were to describe the basic epidemiological characteristics of intussusception and to identify risk factors. A total of 362 children were identified. The highest incidence of intussusception (2.6 per 1,000) was observed in children aged 1-2 years. A total of 58.8% of the children were male, and there was no significant difference in incidence according to the birth year (P = 0.804). Most of the children diagnosed with intussusception underwent air reduction, while only 0.6% had surgery. In all, 82.3% of the children were admitted to the hospital, 0.8% of them had to be admitted to the ICU, and the 6-month mortality was only 0.3%. In this retrospective, observational study, the incidence of intussusception was highest among children between 1 and 2 years of age. Most of the children underwent air reduction.

IntroductionAn accurate understanding of the current status of dog-bite injuries in Korea is essential for establishing preventive strategies. There have been no national reports about dog-bite injuries in Korea. This study investigated dog-bite injuries in Korea that were registered in the nationwide injury surveillance database and analysed the risk factors for significant dog-bite injury.MethodsA multicentre cross-sectional study was conducted using the emergency department (ED)-based Injury In-depth Surveillance (EDIIS) registry in Korea between 2011 and 2016. We defined significant injury as death, admission, surgery, or fracture or amputation. A multivariable logistic regression model was used to obtain the adjusted odds ratios (aORs) for the factors associated with significant dog-bite injuries.ResultsAmong 1,537,617 injured patients, 9,966 (6.5 per 1,000 injured patients) presented to the ED for dog-bite injuries (5.6 in 2011 to 7.6 in 2016, P for trend < 0.001), and 489 (4.9%) were significant injuries. In the age-specific analysis, there were increasing trends only among teenagers (12-18 years) and adults (> 18 years). Being elderly (≥ 60 years) (aOR: 2.70, 95% CI: 2.15-3.39), having injuries to multiple anatomic sites (aOR: 4.37, 95% CI: 2.96-6.45), being bitten outdoors (aOR: 2.71, 95% CI: 2.20-3.34), and being bitten by a relative's dog (aOR: 2.37, 95% CI: 1.09-5.17) were strongly associated with significant dog-bite injury.ConclusionDog-bite injuries are increasing in Korea, especially in teenagers and adults. A relative's or neighbour's dog may be more dangerous than a stranger's dog. Preventive strategies are needed to prevent dog-bite injuries in adults and children.

Knowing a pediatric patient's weight is crucial in resuscitation since the decision on the dose of resuscitation drug and the size of the instrument is made mostly based on a patient's weight. However, using a scale may not always be practical in resuscitation. Therefore, it is important to know the methods of weight estimation in resuscitation. The weight estimation can be performed based on various factors: visual assessment, age, height, and body habitus. One of the most common problems of these methods is that the weight tends to be underestimated as a patient's age increases. This is due to an inappropriate reflection of body habitus. Further research is needed to overcome this problem.

Herlyn-Werner-Wunderlich (HWW) syndrome is a rare, congenital genitourinary anomaly involving the Müllerian and Wolffian structures, and is characterized by the triad of uterine didelphys, obstructed hemivagina, and ipsilateral renal agenesis. It usually presents in adolescent girls in whom hematometrocolpos produces a pronounced mass effect and pain on the side of the obstructed hemivagina. Accurate diagnosis and surgical treatment can be delayed for several months or even years. Here, we report a case of a 12-year-old girl who presented to the emergency department with lower abdominal pain and mass that had lasted for 2 weeks. After the confirmation of HWW syndrome with magnetic resonance imaging, hysteroscopic septostomy was carried out as a definitive treatment. When we evaluate adolescent girls with lower abdominal pain and mass, we should consider the possibility of HWW syndrome.

Patients usually receive cardiopulmonary resuscitation during ventilatory expiration and with their arms down, which does not reflect the normal imaging position. This study used scout images from low-dose chest computed tomography to compare the locations of the left ventricle (LV) in the expiration with arms down position (EAD) and in the full inspirational with arms raised position (IAR).This cross-sectional study used a convenience sample and evaluated scout images that were obtained during screening with the participants in the EAD and IAR positions. The effective compression point was defined as being on the sternum above the longest anteroposterior diameter (APD) of the LV (using axial computed tomography images). The sternum was divided into three parts and the heart's position was evaluated on the EAD and the IAR images, and the distance from the xiphoid process to the LV's sternum landmark (XLVD) was measured. We also examined the compressible organs during CPR based on the EAD and IAR images.We enrolled 127 participants. The LVs were located in the middle of the sternum at EAD for 117 participants (92%) and in the lower half of the sternum at IAR for 107 participants (84%). The mean XLVD was significantly different between the EAD and IAR positions (mean: 85 ± 21 mm vs. 33 ± 17 mm, respectively). The liver's left lobe was located in the lower half of the sternum at EAD for 118 participants (93%).These findings indicate that the location of the LV during cardiopulmonary resuscitation might be in the middle of the sternum if the patient is treated in the EAD position.

Objective Cardiac computed tomography (CCT) is useful for evaluation of acute chest pain in the emergency department (ED). Though the test needs proper interpretation by someone with expertise in cardiovascular imaging, the critical nature of the information the test provides frequently lead emergency physicians (EPs) to act on their own interpretation. We performed this study to assess how often EPs’ interpretations are in agreement with radiologists’. Methods This study is a prospective observational study. The target population was patients assessed with CCT for acute chest pain or discomfort. EPs with at least one year CCT experience underwent a one-hour training session before study participation. The most significant lesion, if any, in each arterial segment was assessed for coronary stenosis and plaque calcification. The agreement between EPs’ and radiologists’ interpretation was assessed with Cohen’s kappa and Gwet’s AC1. Results One hundred and three patients were enrolled and 412 segments were analyzed. Stenosis grading was identical in 363 segments (88.1%) and the interrater agreement was good (kappa=0.6439, AC1=0.8810). Similarly, the plaque calcification grading was identical in 354 segments (86.6%) and the kappa and AC1 values were 0.5660 and 0.8501, respectively. EPs classified 6 of the 17 arterial segments with significant stenosis reported by radiologists as non-significant stenosis (n=5) or clear (n=2), all of which were proved to be significant by following subsequent invasive coronary angiography. Conclusion There was substantial discordance of CCT interpretation between EPs and radiologists. For now, EPs need more education prior to independent CCT reading.

Purpose The purpose of this study is to investigate the effect of oral ondansetron on the incidence of vomiting in children who receive intramuscular (IM) ketamine for procedural sedation and analgesia in the emergency department (ED). Methods In this double-blind, randomized, placebo-controlled trial in a children's hospital ED, patients receiving IM ketamine (5 mg/kg) for ED procedures were randomized to receive either oral ondansetron (2 mg or 4 mg) or placebo 15 minutes before the ketamine injection. We recorded whether vomiting occurred in the ED postsedation or up to 12 hours after discharge with telephone follow-up and compared ED length of stay and parental satisfaction. Results Thirty two children were randomized to placebo and 31 to ondansetron. The groups were similar in age, sex, and fasting duration. ED vomiting was no significant difference with ondansetron: 7 of 31 (22.6%) versus 6 of 32 (18.8%), P=0.707, difference -3.8 (95% confidence interval -23.8% to 16.2%). Follow-up completed in 82.5%. The vomiting in the ED or after discharge in two groups, there was no significant difference: 7 of 27 (25.9%) versus 12 of 25 (48.0%), P=0.165, difference 22.1% (95% confidence interval -3.5% to 47.7%). ED length of stay and parental satisfaction were similar between groups. Conclusion There is no significant reduction of the incidence of vomiting in oral ondansetron group with IM ketamine procedural sedation in children.

Purpose The purpose of this paper is to assess the experience and satisfaction of the trainees participating in the Emergency Pediatric Ultrasound Training Course, which has been developed from a close cooperation between the Korean Society of Pediatric Emergency Medicine and Society of Emergency and Critical Care Imaging. Methods A task-force team was formed consisting of 8 members, collectively from both Korean Society of Pediatric Emergency Medicine and Society of Emergency and Critical Care Imaging. Over 9 separate discussion sessions, the team reviewed related articles to reach a consensus on an educational framework, a curriculum for the training course, and teaching methods to adapt to the conditions of Pediatric Emergency Medicine in South Korea. Results After running the course twice with a developed curriculum, the trainees were polled for their training experiences. A total of 36 trainees completed the course. The response rates were 81.3% and 40% in the first and second course, respectively. On average, the ratings by participants in the survey were above a 4 for all questions, which are significantly high scores. Over sixty percent of participants rated 4 or above in the Likert scale for all of the questions. Conclusion Korean Society of Pediatric Emergency Medicine and Emergency Imaging Study Group (now renamed to Society of Emergency & Critical Care Imaging) successfully developed the Emergency Pediatric Ultrasound Course, which was rated significantly favorably by the trainees.

Intussusception is the most common cause of gastrointestinal obstruction in children, which occurs most commonly in children aged between 3 and 12 months. Small bowel intussusception is uncommon in children compared to adults, and is not reduced by air reduction, unlike illeocecal intussusception. During the post-enema reduction period, patients could experience a delayed complication of hypovolemic shock. We report a case of small bowel intussusception that required explorative laparotomy due to hypovolemic shock. The patient was a 5 month-old female infant, who was diagnosed with small bowel intussusception and small bowel obstruction by sonography after a second air enema reduction. While observing her symptom, the patient's vital sign was becoming increasingly unstable. The patient received a large amount of fluid and inotropics. After a diagnostic computed tomography (CT) scan, the patient underwent explorative laparotomy to rule out bowel ischemia or necrosis. However, the patient's bowel was clear without minimal laceration on the surface of the bowel. After the operation, the patient recovered spontaneously. We suspect the patient's symptom and sign were caused by hypovolemia due to prolonged bowel ischemia and obstruction. Furthermore, resolving hypovolemic shock was caused by small bowel intussusception self-reduction. When pediatric physician is faced with small bowel intussusception in pediatric patients, they should provide adequate fluid supply and management along patient's state.

Significant pancreatic injuries can occur with minor handlebar trauma. Timely diagnosis of pancreatic injuries is critically important, since delayed diagnosis is the greatest determinant of morbidity. Children presenting to the emergency department after bicycle accidents should be treated with a high concern of suspicion regarding combined intra-abdominal trauma. The standard clinical approach of repeated regular physical examination and the use of abdomen CT examination should be followed. We report a case of pancreatic injury after blunt trauma by a bicycle handlebar. This 7-year-old boy experienced spleen preserving distal pancreatectomy with cholecystectomy. The initial symptom and signs were vague or uncertain. However, he revisited the emergency department with aggravated abdominal pain and vomiting. In conclusion, handlebar injuries must be considered potentially serious, no matter how trivial the accident may appear.

ObjectivesThe purpose of this study was to evaluate the therapeutic effect of three different types of sounds on tinnitus patients undergoing tinnitus retraining therapy (TRT).MethodsThis is a single-institution retrospective study, performed in one tertiary otological referral center. Thirty-eight adults with subjective idiopathic tinnitus who were followed for at least 9 weeks were enrolled. Sound therapy was delivered in 3 different ways: narrowband noise TRT (nTRT); mixed band noise TRT (mTRT); broadband noise TRT (bTRT). Treatment response was measured through validated psychometric questionnaires: Tinnitus Handicap Inventory (THI), visual analog scale (VAS) on annoyance, and numerical description of hours of tinnitus perception (awareness hours).ResultsA total of 38 patients were followed for at least 9 weeks. In nTRT group, all outcome measures including THI, VAS, and the awareness hours, decreased over 9 weeks with no statistical significance. In mTRT group, all outcome measures except for awareness hours significantly improved 9 weeks after the beginning of the treatment. In bTRT group, all outcome measures decreased significantly in 9 weeks. When therapeutic success is defined as improvement in THI 7 or more, bTRT group (77.8%) showed a higher success rate than other groups for 38 patients with the minimum follow-up of 9 weeks.ConclusionAll three sounds can provide relief in patients with annoying tinnitus after TRT. However, there is difference in the therapeutic effect according to sound types. Broadband sound seems to be better than narrowband sound or mixed sound in relieving the patients from tinnitus. Therefore, sound therapy with broadband noise may be more appropriate during TRT, but further evidence is needed for precise conclusion.

ObjectivesRectified vestibular evoked myogenic potential (rVEMP) is new method that simultaneously measures the muscle contraction power during VEMP recordings. Although there are a few studies that have evaluated the effect of the rVEMP, there is no study that has evaluated the capacity of rVEMP during asymmetrical muscle contraction.MethodsThirty VEMP measurements were performed among 20 normal subjects (mean age, 28.2±2.1 years; male, 16). VEMP was measured in the supine position. The head was turned to the right side by 0°, 15°, 30°, and 45° and the VEMPs were recorded in each position. The interaural amplitude difference (IAD) ratio was calculated by the conventional non-rectified VEMP (nVEMP) and rVEMP.ResultsThe nVEMP IAD increased significantly according to increasing neck rotation. The IAD in rVEMP was almost similar from 0° to 30°. However, the IAD was significantly larger than the other positions when the neck was rotated 45°. When IAD during 0° was set as a standard, the IAD of the rVEMP was significantly smaller that the nVEMP only during the 30°rotaion.ConclusionRectified VEMP is capable of correcting asymmetrical muscle contraction power. In contrast, it cannot correct the asymmetry if muscle contraction power asymmetry is 44.8% or larger. Also, it is not necessary if muscle contraction power asymmetry is 22.5% or smaller.

Noise-induced hearing loss is a common type of hearing loss. The effects of laser therapy have been investigated from various perspectives, including in wound healing, inflammation reduction, and nerve regeneration, as well as in hearing research. A promising feature of the laser is its capability to penetrate soft tissue; depending on the wavelength, laser energy can penetrate into the deepest part of the body without damaging non-target soft tissues. Based on this idea, we developed bilateral transtympanic laser therapy, which uses simultaneous laser irradiation in both ears, and evaluated the effects of bilateral laser therapy on cochlear damage caused by noise overexposure. Thus, the purpose of this research was to assess the benefits of simultaneous bilateral laser therapy compared with unilateral laser therapy and a control. Eighteen Sprague-Dawley rats were exposed to narrow-band noise at 115 dB SPL for 6 h. Multiple auditory brainstem responses were measured after each laser irradiation, and cochlear hair cells were counted after the 15th such irradiation. The penetration depth of the 808 nm laser was also measured after sacrifice. Approximately 5% of the laser energy reached the contralateral cochlea. Both bilateral and unilateral laser therapy decreased the hearing threshold after noise overstimulation in the rat model. The bilateral laser therapy group showed faster functional recovery at all tested frequencies compared with the unilateral laser therapy group. However, there was no difference in the endpoint ABR results or final hair cell survival, which was analyzed histologically.

Anaphylaxis is a severe systemic allergic reaction, which progresses rapidly and may cause death. However, the diagnosis of anaphylaxis is difficult because initial symptoms and signs of anaphylaxis have various patterns. We reported a case of anaphylaxis with unusual clinical presentation that made diagnosis difficult. A 14-year-old male presented emergency department with dizziness and temporary hypotonia. While observing his symptom, the patient’ s blood pressure decreased rapidly. After thorough history taking, we found out that he had been suffered from pruritus and nausea for two days. The patient received a large volume of crystalloid and intramuscular epinephrine. And the blood pressure recovered soon. When physicians evaluate patients with respiratory or circulatory compromise, we should consider the possibility of anaphylaxis through careful history taking and administer epinephrine immediately if necessary.

ObjectivesAminoglycosides are commonly used antibiotic agents, and they are known to generate free oxygen radicals within the inner ear and to cause vestibulo-cochlear toxicity and permanent damage to the sensory hair cells and neurons. Melatonin, a pineal secretory product, has the properties of being a powerful direct and indirect antioxidant. The aim of the present study was to prove the antioxidant effect of melatonin against gentamicin-induced ototoxicty.MethodsThe utricular maculae of Sprague-Dawley rats were prepared from postnatal day 2-4, and these maculae were were divided into 6 groups as follows: 1) control, 2) melatonin only, 3) gentamicin only, and 4), 5), and 6) gentamicin plus melatonin (10, 50, and 100 µM, respectively). To count the number of hair cells, 5 utricles from each group were stained with phalloidin-FITC on the 1st, 4th, and 7th days after drug administration. Reactive oxygen species (ROS) was assessed by using the fluorescent probe hydrofluorescent diacetate acetyl ester. The caspase-3 activity was also examined with using the fluorescent caspase-3 substrate and performing Western blotting.ResultsThe result of this study showed that gentamicin induced the loss of utricular hair cells, and this loss of hair cells was significantly attenuated by co-administration of melatonin. Melatonin reduced ROS production and caspase-3 activation in the gentamicin treated utricular hair cells.ConclusionOur findings conclusively reveal that melatonin has protective effects against gentamicin-induced hair cell loss in the utricles of rat by inhibiting both ROS production and caspase-3 activity.