The year 2019 was the 30th anniversary of the Korean Society of Emergency Medicine (KSEM) and the 18th International Congress of Emergency Medicine (ICEM) was held in Seoul, Korea. During the last 30 years, Korean emergency medicine has developed and grown enormously, not only in quantity but also in quality. Thus, it is an appropriate occasion to review the history of the KSEM, the three elements of its development, and the challenges to be met. The three major factors contributing to the development of emergency medicine in Korea are the training of emergency medical personnel, the enactment of the emergency medical law, and the creation of an emergency medical fund. The interaction of these three factors has had a synergistic effect on the development of Korean emergency medicine. The challenges to be resolved include the fragmented emergency medical system divided between the fire department and emergency medical centers, the failure of the patient transport system according to the classification of roles for each type of emergency medical center, insufficient quality control in prehospital treatment, and the lack of clarity for the scope of work of emergency medical technicians in the prehospital phase.

Objective: When rescuers move from ambulance to resuscitation area, they press the chest with one-hand by the stretchers. The purpose of this study was to investigate the effect of one-hand chest compression on unfolded stretchers and analyze the characteristics of rescuers that affect compression.
Methods: A manikin simulation study was planned. A total of 28 participants performed one-hand chest compression for one minute to a manikin on the unfolded stretchers. The depth of compression, the extent of recoil and compression frequency were measured, and the results were analyzed. Correlation analysis was done between participant characteristics and depth and frequency of compression. Linear regression analysis was done for variables with significant correlation.
Results: Four participants were excluded due to wrist or shoulder pain. A total of 24 participants (13 male; 11 female) were enrolled. The mean depth of compression was 34.88±11.06 cm; the mean extent of recoil was 50.00±0 cm. The mean frequency of compression was 104.71±11.07 per minute. The extent of recoil and frequency of compression were satisfied with cardiopulmonary resuscitation (CPR) guidelines. The depth of compression was highly correlated with participants' sex (r=-0.88), height (r=0.86), and weight (r=0.78). When adjusted for sex, the depth of compression increased as height and weight increased.
Conclusion: Mechanical chest compression device should be used when CPR is required while moving a cardiac arrest patient by the stretchers. If CPR needs to be done manually, moving distance should be minimized. Finally, a new type of stretcher that fits the body shape of Koreans should be developed.

Objective: Emergency department-based screening clinic (ED-BSC) is a new concept. It is a multifunctional clinic at the entrance of the emergency department (ED) that serves as a screening center for suspected coronavirus disease 2019 (COVID-19) patients and triaging patients and provides basic emergency treatment. We aimed to analyze the current status of the COVID-19 ED-BSC and determine the factors when assigning suspected COVID-19 patients to the negative pressure isolation rooms (NPIRs) at the ED.
Methods: Data of patients who visited the ED-BSC between February 7, 2020, and April 30, 2020, were obtained retrospectively. The data of the patients who underwent the COVID-19 screening test per the standards of the Korea Disease Control and Prevention Agency were analyzed.
Results: A total of 1,378 patients who visited the ED-BSC were included in the study. Of these, 1,226 patients were allowed to go home after the COVID-19 screening test, and 152 patients were assigned to the NPIRs. In univariate analysis, factors influencing the allocation of NPIRs were old age, history of overseas travel within the last 14 days, fever and peripheral oxygen saturation. The multivariate regression analysis confirmed that older adults, history of overseas travel within the last 14 days and fever influenced the allocation of patients to NPIRs.
Conclusion: This study elucidates the current status of suspected COVID-19 patient visits to an ED-BSC. This study may serve as a basis for the establishment and revision of clinical guidelines for ED-BSC.

Objective: The characteristics and prognosis of out-of-hospital cardiac arrest (OHCA) patients can vary due to a variety of factors, including the time of the day. We tried to identify the characteristics and prognosis of OHCA in a Korean metro city based on the time of the day.
Methods: This citywide retrospective observational study was conducted from January 1, 2015, to November 31, 2020, in Daegu, Korea on patients over 18 years of age who were suspected of having a medical etiology of OHCA. We evaluated the characteristics and outcomes of OHCA, according to the time of day, divided into dawn (00:00-05:59), morning (06:00-11:59), afternoon (12:00-17:59), and night (18:00-23:59). The outcome variables were survival to hospital discharge and favorable neurological outcomes.
Results: The median age of the total of 4,783 OHCA patients in the study was 72.0 years of which 3,096 (64.7%) were males. The number of patients who survived was 317 (7.8%) and 301 (6.3%) were discharged with favorable neurological outcomes. There were 672 (14.0%) patients admitted at dawn, 1,607 (33.6%) in the morning, 1,379 (28.8%) in the afternoon, and 1,125 (23.5%) at night. After adjusting for the possible confounding variables, compared with the morning group, the survival to hospital discharge was low in the afternoon and the night (adjusted odds ratio [aOR], 0.69; 95% confidence interval [CI], 0.48-0.98 and aOR, 0.48; 95% CI, 0.32-0.74). In addition, favorable neurological outcomes were also low in the afternoon and the night compared with the morning (aOR, 0.59; 95% CI, 0.40-0.85 and aOR, 0.62; 95% CI, 0.41-0.93).
Conclusion: Diurnal differences in OHCA outcomes were observed. Identification of the diurnal OHCA characteristics will be necessary to devise an appropriate regional emergency medical services strategy.

Objective: The factors related to injury severity in accidents in Korea are unclear. This study helps primary physicians treat victims of traffic accidents with a high probability of severe injury during the initial evaluation in the emergency department (ED).
Methods: This study was conducted on patients who visited Pusan National University Hospital regional trauma center, Korea, between January 2017 and December 2019 due to involvement in automobile accidents as a driver. Multivariate logistic regression analysis was used to determine the relationship of factors with injury severity.
Results: A total of 973 patients were included. Of them, 316 (32.5%) were severely injured. In the multivariate logistic regression analysis, older age was significantly associated with more severe injury (odds ratio [OR], 1.030; 95% confidence interval [CI], 1.017-1.043; P<0.001). A significant difference was noted in injury severity according to the mode of transportation to the ED. Transportation via private ambulance was associated with more severe injury than via public ambulance (OR, 5.853; 95% CI, 3.986-8.594; P<0.001). The severe injury was more likely when the collision involved a large-sized vehicle (OR, 2.369; 95% CI, 1.466-3.826; P<0.001), or a fixed object (OR, 2.077; 95% CI, 1.326-3.254; P<0.001) compared to a small-sized vehicle. The group that did not wear a seat belt had more severe injuries than those who wore a seat belt (OR, 2.218; 95% CI, 1.421-3.463; P<0.001).
Conclusion: Injury severity was correlated with age, mode of transportation to the ED, type of collision and seat belt use. These results will help primary physicians assess critically ill patients.

Objective: Early prediction of the multiple organ dysfunction syndrome (MODS) and providing early innovative treatment may improve outcomes in patients with severe trauma. Lactate and serum albumin levels, which are widely used markers predicting the severity of critically ill patients, tend to diverge during clinical deterioration. This study aimed to evaluate the clinical utility of the lactate/albumin ratio (LAR) as a predictive factor for MODS and 30-day mortality in patients with severe trauma.
Methods: This retrospective, observational cohort study was performed with patients prospectively integrated into a critical pathway for trauma. We analyzed severe trauma patients (Injury Severity Score≥16) admitted to the emergency department (ED), between January 1, 2011, and May 31, 2017. The outcomes were the development of MODS and 30- day mortality.
Results: In total, 348 patients were enrolled, of which 18 (5.2%) died within 96 hours of ED admission, and the remaining 330 patients (94.8%) were evaluated for the development of MODS. An increase in the LAR at admission (odds ratio, 1.618; P=0.028) was an independent predictor of MODS development. The area under the receiver operating characteristic curve (0.755) and Harrell's C-index (0.783) showed that LAR could predict MODS and 30-day mortality.
Conclusion: Initial LAR is an independent predictor of MODS development in patients with severe trauma. Our study results suggest that an elevated LAR can be a useful prognostic marker in patients with severe trauma.

Objective: This study aimed at analyzing the clinical characteristics of patients visiting the emergency department (ED) and pre-triage clinic during the coronavirus disease 2019 (COVID-19) pandemic era in Daegu, South Korea.
Methods: We conducted a retrospective observational study by using the medical records of patients who visited the ED and pre-triage clinic from February 22 to March 31, 2020 and comparing them with the corresponding period in 2019.
Results: The number of patients visiting the ED per day decreased from 122 (115-138) to 77 (66-93). The percentage of patients with respiratory infection increased from 6.6% to 15.4% (P<0.001). The length of the ED stay increased from 269 (150-562) to 559 (293-941) minutes, especially in patients with fever (P<0.001). The rate of injured and less urgent patients decreased from 24.7 to 13.2 and 53.4% to 50.2%, respectively (P<0.001). Sixty-one-point nine percent of patients visiting the ED were triaged and discharged at the pre-triage clinic without entering the ED.
Conclusion: In the COVID-19 pandemic era, there was an increase in the proportion of patients with fever and respiratory symptoms and a decrease in the proportion of injured patients. At the pre-triage clinic, a significant number of patients with suspected COVID-19 or less urgent conditions were treated and discharged without their having to enter the ED.

Objective: The length of stay in the emergency department (ED) is a major contributor to ED overcrowding, which in turn negatively affects the quality of emergency care. Several efforts have been made to reduce the ED length of stay (EDLOS), including a mandatory target to limit ED-LOS within certain parameters. However, the association between EDLOS and treatment results is yet to be clarified. The authors investigated the influence of ED-LOS on patient survival by comparing severity-adjusted survival.
Methods: This study was a retrospective analysis of data registered in 2018 in the National Emergency Department Information System (NEDIS). Cases registered by the regional and local emergency centers were included for analysis. The standardized W scores (Ws) based on the Emergency Department Initial Evaluation Score were used to assess treatment outcomes represented by severity-standardized survival, and the correlation between the Ws and the ED-LOS was analyzed.
Results: A total of 2,281,526 cases were included for analysis. The overall mortality comprised 52,284 cases (2.3%) and the median ED-LOS was 165 minutes (interquartile range, 96-301). Although a longer ED-LOS was associated with poorer outcomes overall, the association was not apparent when an analysis of cases eligible for ED-LOS evaluation in the national evaluation program was carried out. Moreover, in the analysis of severe cases with a predicted survival probability of less than 0.9, an ED-LOS shorter than 6 hours was associated with significantly poorer severity-adjusted survival.
Conclusion: The study revealed that the current ED-LOS criteria used in the national evaluation program were not associated with better survival.

Objective: This study aimed to investigate the impact of the coronavirus disease 2019 (COVID-19) outbreak on the emergency department length of stay (ED-LOS) and outcomes of patients admitted with pneumonia.
Methods: This was a retrospective observational study that included adult pneumonia patients admitted to the emergency department during the period from February to July 2019 and the corresponding period in 2020. After the COVID- 19 outbreak, many changes occurred in medical systems, causing prolonged ED-LOS. We divided ED-LOS into pre-, mid-, and post-ED-LOS and compared ED-LOS, hospital LOS and in-hospital mortality rates of pneumonia patients during the above-mentioned periods. In addition, a multivariable logistic regression analysis was performed to identify the risk factors leading to in-hospital mortality in 2020.
Results: A total of 365 patients were included in the study. Pre-ED-LOS, mid-ED-LOS, post-ED-LOS, and in-hospital mortality in the 2020 group were significantly higher than those of the 2019 group (P<0.05). Mid-ED-LOS (odds ratio [OR], 1.474; P=0.001) and post-ED-LOS (OR, 1.098; P=0.024) were identified as being independently associated with an increased risk of in-hospital mortality in 2020.
Conclusion: Our study shows that ED-LOS and in-hospital mortality increased after the COVID-19 pandemic. Mid-EDLOS and post-ED-LOS were independently associated with an increased risk of in-hospital mortality in patients with pneumonia in 2020.

Objective: We aimed to investigate the characteristics and prognostic factors of coronavirus disease 2019 (COVID-19) patients in the emergency departments (EDs) in Daegu, Korea, the region with the second regional outbreak worldwide.
Methods: We conducted a retrospective observational multicenter study using a population-based COVID-19 registry of EDs. We included the demographic, clinical and laboratory data. Cox proportional hazard regression analysis was performed to identify the prognostic factors of mortality.
Results: A total of 241 patients were included in this study. In the Cox hazard regression model (hazard ratio [95% confidence interval]), age (65-79 years: 3.531 [1.529-8.156], ≥80 years: 5.335 [2.229-12.770]), respiratory rate (RR) (>20 breaths/min: 2.025 [1.205-3.403], ≤11 breaths/min: 111.292 [30.845-401.555]), lymphocyte counts < 1.0×109/L (2.611 [1.494-4.739]), blood urea nitrogen (BUN) levels >23 mg/dL (2.047 [1.233-3.399]), aspartate aminotransferase (AST) levels> 40 IU/L (1.785 [1.009-3.158]) and neutrophil counts>6.3×109/L (1.638 [1.014-2.644]) were associated with mortality.
Conclusion: Age, RR, lymphocyte counts, BUN levels, AST levels and neutrophil counts were prognostic factors in COVID-19 patients in the ED. These factors can help effectively treat and reduce mortality through optimized management of COVID-19 patients, in places with limited emergency medical resources such as massive regional outbreaks.