Purpose: The study was performed to examine the error associated with image superimposition when computed tomography (CT) images of the dental region are substituted with dental scan data, according to the block-out material used in dental impressions. Materials and Methods: A typodont model was created by bonding orthodontic brackets to teeth on plaster dental stones using melted dental base-plate wax. In the experiment, 2 groups were compared: one using wax and the other using putty as the block-out material to prevent tearing of the impression material during the acquisition of dental impressions. In the wax group, dental cast digital data were superimposed onto the CT data of the typodont model using a tooth occlusal surface-based registration method. In the putty group, a surface-based registration method was used that incorporated not only the occlusal surfaces of the teeth, but also the area where the radiopaque putty covered the orthodontic brackets. The absolute value of the error on the dental surfaces was measured for comparisons. Results: Analysis of the scanned areas used for replacement in dental CT images revealed fewer superimposition errors when considering only the tooth occlusal surface area, excluding the area containing putty impression material. Conclusion The clinical recommendation is to block out the orthodontic bracket with radiolucent wax when obtaining dental impressions. Furthermore, only dental occlusal surface-based registration should be used for the superimposition and replacement of the CT image of the dental area with scanned data from a dental cast model.

Purpose: The study was performed to examine the error associated with image superimposition when computed tomography (CT) images of the dental region are substituted with dental scan data, according to the block-out material used in dental impressions. Materials and Methods: A typodont model was created by bonding orthodontic brackets to teeth on plaster dental stones using melted dental base-plate wax. In the experiment, 2 groups were compared: one using wax and the other using putty as the block-out material to prevent tearing of the impression material during the acquisition of dental impressions. In the wax group, dental cast digital data were superimposed onto the CT data of the typodont model using a tooth occlusal surface-based registration method. In the putty group, a surface-based registration method was used that incorporated not only the occlusal surfaces of the teeth, but also the area where the radiopaque putty covered the orthodontic brackets. The absolute value of the error on the dental surfaces was measured for comparisons. Results: Analysis of the scanned areas used for replacement in dental CT images revealed fewer superimposition errors when considering only the tooth occlusal surface area, excluding the area containing putty impression material. Conclusion The clinical recommendation is to block out the orthodontic bracket with radiolucent wax when obtaining dental impressions. Furthermore, only dental occlusal surface-based registration should be used for the superimposition and replacement of the CT image of the dental area with scanned data from a dental cast model.

Purpose: The study was performed to examine the error associated with image superimposition when computed tomography (CT) images of the dental region are substituted with dental scan data, according to the block-out material used in dental impressions. Materials and Methods: A typodont model was created by bonding orthodontic brackets to teeth on plaster dental stones using melted dental base-plate wax. In the experiment, 2 groups were compared: one using wax and the other using putty as the block-out material to prevent tearing of the impression material during the acquisition of dental impressions. In the wax group, dental cast digital data were superimposed onto the CT data of the typodont model using a tooth occlusal surface-based registration method. In the putty group, a surface-based registration method was used that incorporated not only the occlusal surfaces of the teeth, but also the area where the radiopaque putty covered the orthodontic brackets. The absolute value of the error on the dental surfaces was measured for comparisons. Results: Analysis of the scanned areas used for replacement in dental CT images revealed fewer superimposition errors when considering only the tooth occlusal surface area, excluding the area containing putty impression material. Conclusion The clinical recommendation is to block out the orthodontic bracket with radiolucent wax when obtaining dental impressions. Furthermore, only dental occlusal surface-based registration should be used for the superimposition and replacement of the CT image of the dental area with scanned data from a dental cast model.

Objective: The 2020 Cardiopulmonary Resuscitation (CPR) guidelines recommend the use of feedback devices during CPR training and do not limit their use in actual CPR. Although there have been various studies on metronome-assisted CPR that use a metronome as a feedback device, there are no research results to determine a specific metronome setting rate. We analyzed the quality of CPR and the effectiveness of the metronome feedback according to the metronome setting rate within the recommended chest compression rate range. Methods: Fifty healthcare providers who had received CPR training or had performed CPR in the previous 2 years participated, and all of them performed CPR at three rates (100/min, 110/min, and 120/min). The CPR was performed for 2 minutes with only chest compressions. The smartphone metronome (Metronome version 13.0 Android, KHTSXR, Seoul, Korea) application was used for the rate setting, and Resusci Anne QCPR Mk II (Laerdal Medical, Stavanger, Norway) was used to measure the CPR quality. The difference in the CPR quality according to the setting rate was analyzed. Results: There was no significant difference in the “average compression depth (mm),” “adequate compression depth ratio (%),” and “adequate release ratio (%)” at the three set rates. The “adequate compression rate ratio (%)” was 98.48±5.27% at 110/min, which was higher than that at 120/min or 100/min, and this was a statistically significant difference (P=0.000). There was no significant difference in the “adequate compression site ratio (%).” Conclusion When performing metronome-assisted CPR, setting the rate to 110/min can more appropriately maintain the recommended chest compression rate range and can result in high-quality CPR.

Objective: Easy-to-understand information on emergency patient transportation and emergency medical resources is required to operate emergency medical resources appropriately. This study evaluated emergency patient transport routes using a geographic information system (GIS) and converted them into visual information to understand the current status of emergency medical resource use in the region. Methods: The basic data used in this study were collected from the 119 safety centers in Gangwon-do, South Korea, under the fire-fighting headquarters in Gangwon-do from January 2017 to December 2020. The data were analyzed using the geographic information system and converted to visual information. Results: The number of patients with cardiovascular disease, cerebrovascular disease, and traffic accidents was 12,944. Of these, 9,393 patients (72.6%) were transported from Chuncheon city, and 3,551 patients (27.4%) were transported out of Chuncheon city. The number of patients with cardiovascular diseases during the study period was 1,219 (9.4%); 782 patients (64.2%) were transported to the K-EMC (emergency medical center), and 437 patients (35.8%) were transported to the H-EMC. For cerebrovascular disease, 913 patients (7.1%) were transported to the EMC of Chuncheon city, with 585 (64.1%) K-EMC and 328 (35.9%) H-EMC patients. The number of traffic accident patients was 1,266 (9.8%). Five hundred and forty (42.7%) and 726 (57.3%) patients were transported to the K-EMC and H-EMC, respectively. Conclusion The adequacy of facilities, equipment, and human resources required to treat cardiac and cerebrovascular diseases in K-EMC and severe trauma in H-EMC needs to be reviewed.

Objective: The number of elderly patients in Korea has been on the rise recently, and hence the number of out-of-hospital cardiac arrest (OHCA) elderly patients is also rising. The causes of cardiac arrest for the elderly vary, and, it is difficult to predict the recovery of spontaneous circulation (ROSC) in OHCA patients. Therefore, the purpose of this study was to ascertain the predictive value of arterial blood gas analysis (ABGA) results in achieving ROSC in the elderly. Methods: A retrospective analysis of emergency department patients with OHCA was performed at the Kangwon National University Hospital, Korea from 1 January 2016 to 31 December 2019. The initial ABGA results were compared between two patient groups, those who had achieved a return of spontaneous circulation and those who had not. Univariate and multivariable analyses were performed to elucidate the factors associated with ROSC. Results: Overall, 229 OHCA patients were included in the final analysis. The lactate level was independently related to ROSC. A receiver operating characteristics (ROC) curve was plotted to obtain the best cutoff value. The lactate level <9.85 mmol/L showed the largest area under the ROC curve (AUC) to predict ROSC (AUC, 0.666; 95% confidence interval, 0.588-0.743). Multiple regression analysis was performed using the cutoff value, which was a lactate level of 9.85 (odds ratio, 2.907; 95% confidence interval, 1.432-5.902; P=0.003). Conclusion The ABGA results during the cardiopulmonary resuscitation of OHCA patients, showed that the lactate level was an independent factor associated with ROSC. The lactate cutoff value was 9.85 mmol/L.

Objective: Discriminating between pulmonary embolism (PE) and pneumonia in the emergency department (ED) is one of the fastidious tasks. Elderly patients are at more risk of PE and pneumonia than younger patients. This study aimed to determine whether the ratio of D-dimer to C-reactive protein (CRP) could be used as an adjunctive method to differentiate between PE and pneumonia in elderly patients. Methods: Medical records of patients visiting the ED diagnosed with PE and pneumonia were examined. Cutoff values of D-dimer (μg/mL) and the ratio of D-dimer to CRP ([μg/mL]/[mg/dL]) of subjects with PE or pneumonia were analyzed. Results: There were a total of 60 patients with PE and 152 patients with pneumonia. In addition, 15 patients had both PE and pneumonia. The cutoff value of D-dimer to differentiate between PE and pneumonia was 4.26 μg/mL (4,260 ng/mL) (area under curve [AUC], 0.861; sensitivity, 80.0%; specificity, 80.3%; 95% confidence interval [CI], 0.805-0.917). The cutoff value of the ratio of D-dimer to CRP to differentiate between PE and pneumonia was 1.24 ([μg/mL]/[mg/dL]) (AUC, 0.919; sensitivity, 84.4%; specificity, 84.2%; 95% CI, 0.878-0.960). Conclusion The ratio of D-dimer to CRP can be used as an adjunctive method to determine whether a computed tomography pulmonary angiography or a ventilation-perfusion scan can be performed to differentiate between PE and pneumonia in elderly patients.

Objective: Predicting the incidence of emergency patients can be very important for the efficient use of emergency medical resources and the deployment of 119 centers in a pre-hospital setting. The study was conducted to analyze the occurrence of emergency patients using geographic information systems in a pre-hospital setting in Korea. Methods: The basic data used in this study were collected from the 119 centers in Chuncheon-si, Korea, under the firefighting headquarters in Gangwon-do from January 2012 to December 2016. Results: The total number of patients transferred by 119 paramedics was 72,362. Of these, 9,904 (14.7%) were emergency patients; 519 (0.7%) had cardiovascular diseases; 383 (0.5%) had cerebrovascular diseases; 3,043 (4.2%) were trauma patients; 58,413 (80.7%) were non-emergency patients. The occurrence of emergency diseases was slightly lower in the Hyoja-dong area, and it was slightly higher in the area of the outskirts of the city. The incidence of heart disease was low in the Hyoja-dong and Nam-myeon areas, but the incidence of heart disease was highly observed in other areas. The number of trauma patients was 1,265 (41.6%) in the outskirts of the city, a suburban area, showing a relatively higher incidence than other emerging diseases. Conclusion The deployment of ambulances in Chuncheon-si should be carried out considering demographic characteristics and patient occurrence.

Objective: The number of elderly patients in Korea has been on the rise recently, and hence the number of out-of-hospital cardiac arrest (OHCA) elderly patients is also rising. The causes of cardiac arrest for the elderly vary, and, it is difficult to predict the recovery of spontaneous circulation (ROSC) in OHCA patients. Therefore, the purpose of this study was to ascertain the predictive value of arterial blood gas analysis (ABGA) results in achieving ROSC in the elderly. Methods: A retrospective analysis of emergency department patients with OHCA was performed at the Kangwon National University Hospital, Korea from 1 January 2016 to 31 December 2019. The initial ABGA results were compared between two patient groups, those who had achieved a return of spontaneous circulation and those who had not. Univariate and multivariable analyses were performed to elucidate the factors associated with ROSC. Results: Overall, 229 OHCA patients were included in the final analysis. The lactate level was independently related to ROSC. A receiver operating characteristics (ROC) curve was plotted to obtain the best cutoff value. The lactate level <9.85 mmol/L showed the largest area under the ROC curve (AUC) to predict ROSC (AUC, 0.666; 95% confidence interval, 0.588-0.743). Multiple regression analysis was performed using the cutoff value, which was a lactate level of 9.85 (odds ratio, 2.907; 95% confidence interval, 1.432-5.902; P=0.003). Conclusion The ABGA results during the cardiopulmonary resuscitation of OHCA patients, showed that the lactate level was an independent factor associated with ROSC. The lactate cutoff value was 9.85 mmol/L.

Objective: This study analyzed the characteristics of people who attempted suicide that resulted in deaths as compared to that of the suicide survivors. Methods: This study included 799 suicide attempts that occurred from March 1, 2015, to March 31, 2019 at the emergency department of the university hospital in a city of around 300,000 people. Suicide attempts were classified into the survivor and death groups, and the characteristics of each group were compared. The suicide deaths due to re-attempts were also analyzed. Results: There were more males than females in the death groups. There was a high proportion of people aged 50 or older in the death groups. Hanging, carbon monoxide poisoning, and jumping from great heights were the most commonly used methods of suicide in the death groups. In the selected death group, psychiatric symptom, physical illness, and economic problem among the suicidal causes and depressive disorder among the psychiatric diagnoses were factors that increase the risk of suicide death. Sixty-three point four percent of the survival groups and 52.5% of the selected deaths had not received psychiatric care. On the analysis of suicide deaths due to re-attempts, the average number of suicide attempts was 2.45±0.9. The time from the first suicide attempt to the last suicide attempt was 13.8±10.4 months. Conclusion If it is necessary to make a treatment decision for a suicide attempt in a limited time, such as the case of treating a suicide attempter who visits an emergency department, it is necessary to consider the characteristic factors of the death attempts of suicidal people.