Objective: To establish the reference standard of the median nerve conduction study (NCS) in Korea. Methods: A total of 648 median motor and 602 median sensory NCSs from 349 Korean healthy volunteers were tested and analyzed prospectively. Equipment calibration, assessment of intraand inter-rater reliability, and the NCSs per se were conducted according to a predetermined protocol. A reference standard was established from uncertainty components for the following parameters: the onset and peak latencies; the baseline-to-peak and peak-to-peak amplitudes; the area and duration of the negative wave; and the nerve conduction velocity. The effects of sex, age and stimulation intensity were analyzed. Results: Each measured value of 648 median motor and 602 median sensory nerves were obtained and presented with both mean and expanded uncertainties, as well as mean and standard deviations. The cut-off values with expanded uncertainty were determined for different age and sex groups. After adjusting for anthropometric covariates, all parameters except duration were affected by age, and sex appeared to influence both duration and area. While stimulation intensity significantly affected some parameters including latencies, the effect sizes were negligible. Conclusion We propose the median NCS reference standard using the largest Korean dataset ever available. The use of the traceable and reliable reference standard is anticipated to promote more accurate and dependable diagnosis and appropriate management of median neuropathies in Korea.

If cardiac sympathetic activity increases after myocardial injury, a ventricular electrical storm (VES) may occur. The stellate ganglion block is a minimally invasive technique performed to control VES through temporary sympathetic cessation. This case was treated after 3 stellate ganglion blocks in VES developed after non-ST elevation myocardial infarction. This patient underwent prophylactic stellate ganglion block prior to radical nephrectomy for a renal mass found during hospitalization, and the operation was safely completed. Stellate ganglion block is expected to be a safe treatment option for patients with unstable VES.

Objective: To develop a set of reference standards for tibial motor, common peroneal motor, sural sensory, and superficial peroneal sensory nerve conduction studies (NCSs) with expanded uncertainty in a healthy Korean population. Methods: Standardized procedures were conducted for individual lower extremity NCSs of 199 healthy participants in their 20s (n=100) and 50s (n=99). Mean values and expanded uncertainties for parameters were analyzed with thorough consideration of multiple uncertainty factors under the International Guide to the Expression of Uncertainty in Measurement. In addition, side-to-side differences in onset latency, amplitude, and nerve conduction velocity (NCV) were analyzed. Results: Mean (reference range) for distal onset latency, baseline to negative peak amplitude, NCV of tibial motor nerve in males in their 20s were 4.3 ms (3.1–5.4 ms), 7.1 mV (3.4–10.9 mV), and 50.7 m/s (42.2–59.3 m/s), respectively; sural sensory nerve baseline to negative peak amplitude in males in their 20s was 21.7 μV (8.3–35.2 μV). Including the aforementioned data, we present a vast dataset of normative mean values and expanded uncertainties for NCSs of the leg in a healthy Korean population. Furthermore, upper limits for normal side-to-side differences for onset latency, amplitude, and NCV of each nerve are suggested. Conclusion To our knowledge, this is the first study to present the reference standards of leg NCSs with consideration for multifactorial uncertainties in an Asian population. We expect these results to help practitioners make reliable and reproducible clinical decisions.

Background: Ultrasonography (US) is a simple and reliable tool that can aid in the diagnosis of benign subcutaneous lesions such as epidermal cysts and lipomas. Objective: This study aimed to determine the efficacy of US for the differential diagnosis of epidermal cysts and lipomas. Methods: A retrospective study of 100 patients with epidermal cysts (n=45) or lipomas (n=55) who underwent US and then received a pathological diagnosis in the dermatology department of Pusan National University Hospital was conducted. Results: US and clinical impressions accurately diagnosed the epidermal cysts in 90.0% and 88.0% of the patients, respectively, and the lipomas in 92.0% and 88.0% of the patients, respectively. US combined with clinical impression significantly increased the diagnostic yield of epidermal cysts (98%) and lipomas (99%). On US, the frequency of posterior acoustic enhancement was higher for the epidermal cysts than for the lipomas (82.2% and 29.1%, respectively; p＜0.001), and striated echoes such as internal linear echogenic reflections and dark clefts were more frequently found in the lipomas than in the epidermal cysts (90.9% and 6.7%, respectively; p＜0.001). Conclusion This study implies that the diagnostic role of US can be greatly enhanced by knowledge of the clinical presentation.

Objective: This study evaluated the anxiety, work, and socioeconomic burden of emergency physicians (EP) during the coronavirus disease 2019 (COVID-19) pandemic in South Korea. Methods: A cross-sectional observational study was conducted using data from the 2020 Korean Emergency Physician Survey that included the following domains: hospital resources of suspected COVID-19 patients, availability of personal protective equipment, levels of home and workplace anxiety, the severity of work burnout, identification of stressors, changes in personal environments, and measures to decrease stress/anxiety. Results: Totally, 855 eligible participants were enrolled in the study. A statistically significant deterioration was observed in response to decreased working income or an unstable employment situation (0.46±0.88 points). The median number of patients with confirmed COVID-19 was 2.72. The risk of infection during emergency department (ED) work was found to be significantly increased (P<0.01). Of the 751 respondents (91.4%) who reported patient contact during their survey phase, 516 (62.8%) reported having taken the COVID-19 reverse transcription polymerase chain reaction test. The major factors that affected worsening of the work burden were determined to be unsuitable inter-hospital transfer arrangements for febrile patients (3.46±1.06 before vs. 1.99±1.16 after the pandemic, P<0.01) and delayed consultation for patients with fever or respiratory symptoms in the ED (3.20±1.06 before vs. 2.66±1.10 after the pandemic, P<0.01). Conclusion During the peak phase, the COVID-19 pandemic induced substantial workplace and socioeconomic burdens for Korean EPs. The sustained impact of the pandemic on the wellness of EPs deserves further investigation to guide targeted interventions.

Objective: Machine learning is emerging as a new alternative in various scientific fields and is potentially a new method of interpretation. Using the Light Gradient Boosting Machine (LightGBM), we analyzed the factors that influence the rechoice of emergency medicine responders. The survey is a cross-sectional study which provides an accurate understanding of a responder's current status. However, the results may vary depending on the composition, format, and question, and the relationship between the answers may be unclear. Methods: This study evaluated the modified 2020 Korean Emergency Physician Survey raw data. We applied the preferred model for random relationship check, random forest, support vector machine, and LightGBM models. The stacking ensemble model was used for the final decision process. Results: ‘It is fun working in an emergency room’was the most selected response factor for re-choice, followed by ‘interesting major’. The physical burden of age and lack of identity had a negative impact, whereas burnout and emotional stress factors had a lesser effect. Anxiety caused by the coronavirus disease 2019 (COVID-19) is thought to have a significant impact on this decision making. Conclusion Establishing the identity of emergency medicine and being faithful to its fundamental mission is a way to increase the rate of re-choice. Decreasing the burden of workload modified according to age is recommended to establish career longevity. The method of machine learning presents us with a new possibility of checking the relevance of survey results quickly and easily.

Objective: It has been reported that emergency physicians experience high levels of depression and psychological burnout due to night shifts and tend to consider early retirement. This study intended to check working hours and intensity, individual health, satisfaction, and overall welfare, given the increase in the numbers of emergency physicians. Methods: The study used the results of the ‘2020 Korean Emergency Physician Survey (KEPS)’ conducted from January 15 to February 26, 2021, which targeted 2,138 emergency physicians registered with the Korean Society of Emergency Medicine. The survey was conducted online through the web and mobile application. Results: One thousand three hundred seven out of the 2,167 emergency physicians (60.3%) registered at the society responded. The average age of the respondents was 42.6 years, and there were 1,148 male emergency physicians and 158 female emergency physicians. The average professional experience was 8.2 years, with 325 professors, 122 commissioned doctors, 648 public servants of which 90 had military service, and 45 medical practitioners. Conclusion In conclusion, the number of working hours of emergency physicians showed a decreasing trend compared to 2010 and 2015. However, emergency physicians often expected early retirement. This suggests that, while the absolute working hours are decreasing, the actual working intensity has not decreased. For the proper development of the emergency medical system, it is necessary to establish a stable working environment for emergency physicians. A systematic study is needed on the working hours and work intensity of emergency physicians.

Objective: As the history of emergency medicine grows longer, emergency medicine specialists are observed to comprise various age groups. There have been no prior studies on the generation shift analysis of emergency medicine specialists. Our study is designed to identify the characteristics of each generation and predict the generation shift in emergency medicine physicians. Methods: The analysis was based on the results of the 2020 survey of emergency medicine specialists. The study was conducted on 1,307 respondents and finally, the responses of 967 people were analyzed after excluding 199 who were not in charge of emergency room treatments and 141 who gave incomplete responses. The respondents were divided into four groups based on the following generations: first generation (1996-1999), second generation (2000-2008), third generation (2009-2014), and fourth generation (2015-2020), classified by the year in which they acquired their emergency medicine board license. The intergenerational difference analysis was done using the Kruskall-Wallis test. Results: The first generation was characterized by a high proportion of university hospital professors, large non-clinical activity hours, a few night shifts, higher social contributions, low satisfaction with the training and education environment, and a high retirement age compared to the later generations. In the second generation, the characteristics of the first, third, and fourth generations were generally mixed. The third and fourth generations showed similar characteristics overall, though there were differences in some categories. Conclusion There were significant differences by generation in the working environments, motivation for application, and retirement age. This is the first study that quantifies generational differences. Considering these trends, a discussion about the work environment needs to be initiated.

Objective: Emergency physicians are constantly exposed to night shifts and stress due to the nature of their work, resulting in health problems such as substance abuse, depression, and suicidal ideation. To date, depression in Korean emergency physicians has never been investigated. The present study endeavors to identify the prevalence and factors related to depression in emergency physicians in Korea. Methods: The present study retrospectively analyzed data from the 2020 Korean Emergency Physician Survey. The prevalence of depression was evaluated using the PHQ-9 (Patient Healthcare Questionnaire-9). Multivariable logistic regression analysis was used to identify the factors related to depression and other variables. Results: The overall response rate of the survey was 61.3% (1,307/2,138). A total of 1,102 respondents completed the PHQ- 9 and were analyzed. The prevalence of depression was 27.0% (95% confidence interval [CI], 27.8-33.6). Following factors were found to be associated with depression: military service as the type of position (odds ratio [OR], 0.316; 95% CI, 0.126- 0.794), schedule satisfaction (OR, 0.523; 95% CI, 0.356-0.769), health perspective (OR, 0.408; 95% CI, 0.252-0.662), weekly exercise (OR, 0.879; 95% CI, 0.774-0.998), sleep quality (OR, 4.728; 95% CI, 3.329-6.715), regular diet (OR, 0.380; 95% CI, 0.239-0.605), nighttime snacking (OR, 1.607; 95% CI, 1.124-2.298), and job satisfaction (OR, 0.456; 95% CI, 0.305-0.682). Conclusion More than a quarter of respondents had depression. Job satisfaction, schedule satisfaction, and a healthy lifestyle were negatively related to depression. However, poor sleep quality showed a significantly positive association, which suggests the necessity for a long-term follow-up.

Objective: Unlike the temporary nature of an emergency resident's job, the position of an emergency physician is one of a lifelong commitment requiring stability and persistence. However, it is hard to pursue a healthy lifestyle because of the 24 hours a day, 7 days a week (24/7) working schedule. The emergency room environment demands high physical and mental stamina, and hence the health problems of emergency physicians have a significant impact on the patient’s outcome. Our study was designed to analyze the emergency physician’s health status and influencing factors based on the data from the 2020 Korean Emergency Physician Survey. Methods: Based on the results of the survey, the factors affecting health were classified into several categories, such as personal character, working conditions, lifestyle, and emotional status. Statistical methods have been used to determine whether these factors can affect self-rated health. Results: The self-rated health worsened for emergency physicians in their 40s rather than in their 30s. However, drinking, smoking, and eating patterns had no effect on self-rated health. Also, the actual number of shifts was observed to bear no relationship with health. Sleeping, wellness, and mood affected self-rated health. Physicians who felt they were unhealthy, expected an early retirement because of the burden of night shifts. Conclusion Emergency physicians in Korea have a low self-rated health status. Mental stress, exercise, and sleep had an impact on the status. Physicians who served long-term night shifts saw a deleterious effect on their sleep and mood, and this damage was cumulative. The career longevity of an emergency physician thus requires a reasonable night shift schedule and age-modified adjustments.