Status and perception of point-of-care ultrasound education in Korean medical schools: A national cross-sectional study.

As point-of-care ultrasound (POCUS) is increasingly being used in clinical settings, ultrasound education is expanding into student curricula. We aimed to determine the status and awareness of POCUS education in Korean medical schools using a nationwide cross-sectional survey. In October 2021, a survey questionnaire consisting of 20 questions was distributed via e-mail to professors in the emergency medicine (EM) departments of Korean medical schools. The questionnaire encompassed 19 multiple-choice questions covering demographics, current education, perceptions, and barriers, and the final question was an open-ended inquiry seeking suggestions for POCUS education. All EM departments of the 40 medical schools responded, of which only 13 (33%) reported providing POCUS education. The implementation of POCUS education primarily occurred in the third and fourth years, with less than 4 hours of dedicated training time. Five schools offered a hands-on education. Among schools offering ultrasound education, POCUS training for trauma cases is the most common. Eight schools had designated professors responsible for POCUS education and only 2 possessed educational ultrasound devices. Of the respondents, 64% expressed the belief that POCUS education for medical students is necessary, whereas 36%, including those with neutral opinions, did not anticipate its importance. The identified barriers to POCUS education included faculty shortages (83%), infrastructure limitations (76%), training time constraints (74%), and a limited awareness of POCUS (29%). POCUS education in Korean medical schools was limited to a minority of EM departments (33%). To successfully implement POCUS education in medical curricula, it is crucial to clarify learning objectives, enhance faculty recognition, and improve the infrastructure. These findings provide valuable insights for advancing ultrasound training in medical schools to ensure the provision of high-quality POCUS education for future healthcare professionals.

A Pillar/Perfusion Plate Enhances Cell Growth, Reproducibility, Throughput, and User Friendliness in Dynamic 3D Cell Culture.

Static three-dimensional (3D) cell culture has been demonstrated in ultralow attachment well plates, hanging droplet plates, and microtiter well plates with hydrogels or magnetic nanoparticles. Although it is simple, reproducible, and relatively inexpensive, thus potentially used for high-throughput screening, statically cultured 3D cells often suffer from a necrotic core due to limited nutrient and oxygen diffusion and waste removal and have a limited in vivo-like tissue structure. Here, we overcome these challenges by developing a pillar/perfusion plate platform and demonstrating high-throughput, dynamic 3D cell culture. Cell spheroids were loaded on the pillar plate with hydrogel by simple sandwiching and encapsulation and cultured dynamically in the perfusion plate on a digital rocker. Unlike traditional microfluidic devices, fast flow velocity was maintained within perfusion wells and the pillar plate was separated from the perfusion plate for cell-based assays. It was compatible with common lab equipment and allowed cell culture, testing, staining, and imaging in situ. The pillar/perfusion plate enhanced cell growth by rapid diffusion, reproducibility, assay throughput, and user friendliness in a dynamic 3D cell culture.

Dynamic culture of cerebral organoids using a pillar/perfusion plate for the assessment of developmental neurotoxicity.

Despite the potential toxicity of commercial chemicals to the development of the nervous system (known as developmental neurotoxicity or DNT), conventional in vitro cell models have primarily been employed for the assessment of acute neuronal toxicity. On the other hand, animal models used for the assessment of DNT are not physiologically relevant due to the heterogenic difference between humans and animals. In addition, animal models are low-throughput, time-consuming, expensive, and ethically questionable. Recently, human brain organoids have emerged as a promising alternative to assess the detrimental effects of chemicals on the developing brain. However, conventional organoid culture systems have several technical limitations including low throughput, lack of reproducibility, insufficient maturity of organoids, and the formation of the necrotic core due to limited diffusion of nutrients and oxygen. To address these issues and establish predictive DNT models, cerebral organoids were differentiated in a dynamic condition in a unique pillar/perfusion plate, which were exposed to test compounds to evaluate DNT potential. The pillar/perfusion plate facilitated uniform, dynamic culture of cerebral organoids with improved proliferation and maturity by rapid, bidirectional flow generated on a digital rocker. Day 9 cerebral organoids in the pillar/perfusion plate were exposed to ascorbic acid (DNT negative) and methylmercury (DNT positive) in a dynamic condition for 1 and 3 weeks, and changes in organoid morphology and neural gene expression were measured to determine DNT potential. As expected, ascorbic acid didn't induce any changes in organoid morphology and neural gene expression. However, exposure of day 9 cerebral organoids to methylmercury resulted in significant changes in organoid morphology and neural gene expression. Interestingly, methylmercury did not induce adverse changes in cerebral organoids in a static condition, thus highlighting the importance of dynamic organoid culture in DNT assessment.

Reproducible generation of human liver organoids (HLOs) on a pillar plate platform via microarray 3D bioprinting.

Human liver organoids (HLOs) hold significant potential for recapitulating the architecture and function of liver tissues in vivo. However, conventional culture methods of HLOs, forming Matrigel domes in 6-/24-well plates, have technical limitations such as high cost and low throughput in organoid-based assays for predictive assessment of compounds in clinical and pharmacological lab settings. To address these issues, we have developed a unique microarray 3D bioprinting protocol of progenitor cells in biomimetic hydrogels on a pillar plate with sidewalls and slits, coupled with a clear bottom, 384-deep well plate for scale-up production of HLOs. Microarray 3D bioprinting, a droplet-based printing technology, was used to generate a large number of small organoids on the pillar plate for predictive hepatotoxicity assays. Foregut cells, differentiated from human iPSCs, were mixed with Matrigel and then printed on the pillar plate rapidly and uniformly, resulting in coefficient of variation (CV) values in the range of 15 - 18%, without any detrimental effect on cell viability. Despite utilizing 10 - 50-fold smaller cell culture volume compared to their counterparts in Matrigel domes in 6-/24-well plates, HLOs differentiated on the pillar plate exhibited similar morphology and superior function, potentially due to rapid diffusion of nutrients and oxygen at the small scale. Day 25 HLOs were robust and functional on the pillar plate in terms of their viability, albumin secretion, CYP3A4 activity, and drug toxicity testing, all with low CV values. From three independent trials of in situ assessment, the IC50 values calculated for sorafenib and tamoxifen were 6.2 ± 1.6 µM and 25.4 ± 8.3 µM, respectively. Therefore, our unique 3D bioprinting and miniature organoid culture on the pillar plate could be used for scale-up, reproducible generation of HLOs with minimal manual intervention for high-throughput assessment of compound hepatotoxicity.

Reproducible generation of human liver organoids (HLOs) on a pillar plate platform via microarray 3D bioprinting.

Human liver organoids (HLOs) hold significant potential for recapitulating the architecture and function of liver tissues in vivo. However, conventional culture methods of HLOs, forming Matrigel domes in 6-/24-well plates, have technical limitations such as high cost and low throughput in organoid-based assays for predictive assessment of compounds in clinical and pharmacological lab settings. To address these issues, we have developed a unique microarray 3D bioprinting protocol of progenitor cells in biomimetic hydrogels on a pillar plate with sidewalls and slits, coupled with a clear bottom, 384-deep well plate for scale-up production of HLOs. Microarray 3D bioprinting, a droplet-based printing technology, was used to generate a large number of small organoids on the pillar plate for predictive hepatotoxicity assays. Foregut cells, differentiated from human iPSCs, were mixed with Matrigel and then printed on the pillar plate rapidly and uniformly, resulting in coefficient of variation (CV) values in the range of 15-18%, without any detrimental effect on cell viability. Despite utilizing 10-50-fold smaller cell culture volume compared to their counterparts in Matrigel domes in 6-/24-well plates, HLOs differentiated on the pillar plate exhibited similar morphology and superior function, potentially due to rapid diffusion of nutrients and oxygen at the small scale. Day 25 HLOs were robust and functional on the pillar plate in terms of their viability, albumin secretion, CYP3A4 activity, and drug toxicity testing, all with low CV values. From three independent trials of in situ assessment, the IC50 values calculated for sorafenib and tamoxifen were 6.2 ± 1.6 µM and 25.4 ± 8.3 µM, respectively. Therefore, our unique 3D bioprinting and miniature organoid culture on the pillar plate could be used for scale-up, reproducible generation of HLOs with minimal manual intervention for high-throughput assessment of compound hepatotoxicity.

Regenerative human liver organoids (HLOs) in a pillar/perfusion plate for hepatotoxicity assays.

Human liver organoids (HLOs) differentiated from embryonic stem cells (ESCs), induced pluripotent stem cells (iPSCs), and adult stem cells (ASCs) can recapitulate structure and function of human fetal liver tissues, thus, considered as a promising tissue model for liver diseases and predictive compound screening. Nonetheless, there are still several technical challenges to adopt HLOs in the drug discovery process, which include relatively long-term cell differentiation with multiple culture media (3 - 4 weeks) leading to batch-to-batch variation, short-term hepatic function after maturation (3 - 5 days), low assay throughput due to Matrigel dissociation and HLO transfer to a microtiter well plate, and insufficient maturity as compared to primary hepatocytes. To address these issues, expandable HLOs (Exp-HLOs) derived from human iPSCs were generated by optimizing differentiation protocols, which were rapidly printed on a 144-pillar plate with sidewalls and slits (144PillarPlate) and dynamically cultured for up to 20 days into differentiated HLOs (Diff-HLOs) in a 144-perfusion plate with perfusion wells and reservoirs (144PerfusionPlate) for in situ organoid culture and analysis. Dynamically cultured Diff-HLOs were generated robustly and reproducibly in the pillar/perfusion plate with higher maturity as compared to those in statically cultured HLOs by differentiating Exp-HLOs for 10 days. In addition, Diff-HLOs in the pillar/perfusion plate were tested with acetaminophen and troglitazone for 3 days to assess drug-induced liver injury (DILI) and then incubated in an expansion medium for 10 days to evaluate the recovery of the liver from DILI. The assessment of liver regeneration post injury is critical to understand the mechanism of recovery and determine the threshold drug concentration beyond which there will be a sharp decrease in the liver's regenerative capacity. We envision that bioprinted Diff-HLOs in the pillar/perfusion plate could be used for high-throughput screening (HTS) of hepatotoxic compounds due to short-term differentiation of passage-able Exp-HLOs necessary, stable hepatic function after maturation, high reproducibility, and high throughput with capability of in situ organoid culture, testing, staining, imaging, and analysis.

Real-Time Tracheal Ultrasound vs. Capnography for Intubation Confirmation during CPR Wearing a Powered Air-Purifying Respirator in COVID-19 Era.

This study aimed to compare the accuracy of real-time trans-tracheal ultrasound (TTUS) with capnography to confirm intubation in cardiopulmonary resuscitation (CPR) while wearing a powered air-purifying respirator (PAPR). This setting reflects increased caution due to contagious diseases. This single-center, prospective, comparative study enrolled patients requiring CPR while wearing a PAPR who visited the emergency department of a tertiary medical center from December 2020 to August 2022. A physician performed the TTUS in real time and recorded the tube placement assessment. Another healthcare provider attached waveform capnography to the tube and recorded end-tidal carbon dioxide (EtCO2) after five ventilations. The accuracy and agreement of both methods compared with direct laryngoscopic visualization of tube placement, and the time taken by both methods was evaluated. Thirty-three patients with cardiac arrest were analyzed. TTUS confirmed tube placement with 100% accuracy, sensitivity, and specificity, whereas capnography demonstrated 97% accuracy, 96.8% sensitivity, and 100% specificity. The Kappa values for TTUS and capnography compared to direct visualization were 1.0 and 0.7843, respectively. EtCO2 was measured in 45 (37-59) seconds (median (interquartile range)), whereas TTUS required only 12 (8-23) seconds, indicating that TTUS was significantly faster (p < 0.001). No significant correlation was found between the physician's TTUS proficiency and image acquisition time. This study demonstrated that TTUS is more accurate and faster than EtCO2 measurement for confirming endotracheal tube placement during CPR, particularly in the context of PAPR usage in pandemic conditions.

High-throughput assessment of metabolism-mediated neurotoxicity by combining 3D-cultured neural stem cells and liver cell spheroids.

Despite the fact that biotransformation in the liver plays an important role in the augmented toxicity and detoxification of chemicals, relatively little efforts have been made to incorporate biotransformation into in vitro neurotoxicity testing. Conventional in vitro systems for neurotoxicity tests lack the capability of investigating the qualitative and quantitative differences between parent chemicals and their metabolites in the human body. Therefore, there is a need for an in vitro toxicity screening system that can incorporate hepatic biotransformation of chemicals and predict the susceptibility of their metabolites to induce neurotoxicity. To address this need, we adopted 3D cultures of metabolically competent HepaRG cell line with ReNcell VM and established a high-throughput, metabolism-mediated neurotoxicity testing system. Briefly, spheroids of HepaRG cells were generated in an ultralow attachment (ULA) 384-well plate while 3D-cultured ReNcell VM was established on a 384-pillar plate with sidewalls and slits (384PillarPlate). Metabolically sensitive test compounds were added in the ULA 384-well plate with HepaRG spheroids and coupled with 3D-cultured ReNcell VM on the 384PillarPlate, which allowed us to generate metabolites in situ by HepaRG cells and test them against neural stem cells. We envision that this approach could be potentially adopted in pharmaceutical and chemical industries when high-throughput screening (HTS) is necessary to assess neurotoxicity of compounds and their metabolites.

A Pillar and Perfusion Plate Platform for Robust Human Organoid Culture and Analysis.

Human organoids have the potential to revolutionize in vitro disease modeling by providing multicellular architecture and function that are similar to those in vivo. This innovative and evolving technology, however, still suffers from assay throughput and reproducibility to enable high-throughput screening (HTS) of compounds due to cumbersome organoid differentiation processes and difficulty in scale-up and quality control. Using organoids for HTS is further challenged by the lack of easy-to-use fluidic systems that are compatible with relatively large organoids. Here, these challenges are overcome by engineering "microarray three-dimensional (3D) bioprinting" technology and associated pillar and perfusion plates for human organoid culture and analysis. High-precision, high-throughput stem cell printing, and encapsulation techniques are demonstrated on a pillar plate, which is coupled with a complementary deep well plate and a perfusion well plate for static and dynamic organoid culture. Bioprinted cells and spheroids in hydrogels are differentiated into liver and intestine organoids for in situ functional assays. The pillar/perfusion plates are compatible with standard 384-well plates and HTS equipment, and thus may be easily adopted in current drug discovery efforts.

A Pillar and Perfusion Plate Platform for Robust Human Organoid Culture and Analysis.

Human organoids have potential to revolutionize in vitro disease modeling by providing multicellular architecture and function that are similar to those in vivo . This innovative and evolving technology, however, still suffers from assay throughput and reproducibility to enable high-throughput screening (HTS) of compounds due to cumbersome organoid differentiation processes and difficulty in scale-up and quality control. Using organoids for HTS is further challenged by lack of easy-to-use fluidic systems that are compatible with relatively large organoids. Here, we overcome these challenges by engineering "microarray three-dimensional (3D) bioprinting" technology and associated pillar and perfusion plates for human organoid culture and analysis. High-precision, high-throughput stem cell printing and encapsulation techniques were demonstrated on a pillar plate, which was coupled with a complementary deep well plate and a perfusion well plate for static and dynamic organoid culture. Bioprinted cells and spheroids in hydrogels were differentiated into liver and intestine organoids for in situ functional assays. The pillar/perfusion plates are compatible with standard 384-well plates and HTS equipment, and thus may be easily adopted in current drug discovery efforts.

A pillar/perfusion plate enhances cell growth, reproducibility, throughput, and user friendliness in dynamic 3D cell culture.

Static three-dimensional (3D) cell culture has been demonstrated in ultralow attachment well plates, hanging droplet plates, and microtiter well plates with hydrogels or magnetic nanoparticles. Although it is simple, reproducible, and relatively inexpensive, thus potentially used for high-throughput screening, statically cultured 3D cells often suffer from the necrotic core due to limited nutrient and oxygen diffusion and waste removal and have limited in vivo-like tissue structure. Here, we overcome these challenges by developing a pillar/perfusion plate platform and demonstrating high-throughput, dynamic 3D cell culture. Cell spheroids have been loaded on the pillar plate with hydrogel by simple sandwiching and encapsulation and cultured dynamically in the perfusion plate on a digital rocker. Unlike traditional microfluidic devices, fast flow rates were maintained within perfusion wells, and the pillar plate could be separated from the perfusion plate for cell-based assays. It was compatible with common lab equipment and allowed cell culture, testing, staining, and imaging in situ. The pillar/perfusion plate enhanced cell growth by rapid diffusion, reproducibility, assay throughput, and user friendliness in dynamic 3D cell culture.

Combination of chemotherapy and focused ultrasound for the treatment of unresectable pancreatic cancer: a proof-of-concept study.

OBJECTIVES: To investigate the safety and preliminary efficacy of the combined treatment of focused ultrasound (FUS) and chemotherapy (nab-paclitaxel plus gemcitabine, nPac/Gem) for patients with unresectable pancreatic cancer. METHODS: Patients pathologically diagnosed with unresectable pancreatic cancer were included. Low (Isppa = 1.5 kW/cm2), intermediate (2.0 kW/cm2), and high (2.5 kW/cm2) FUS intensity treatment groups were predefined. A 1% duty cycle and the 3+3 scheme were used. Six combined treatments were performed, and adverse events were assessed. Changes in tumor size and tumor response, CA 19-9 level, and patient-reported outcomes at the immediate follow-up (F/U) and/or at the 3-month F/U and survival were evaluated. RESULTS: Three participants were enrolled in each intensity group. No adverse device effect or dose-limiting toxicity occurred in any of the participants. Seven of the nine participants experienced a >15% tumor size decrease at the immediate F/U CT and at the 3-month F/U CT. The CA 19-9 level decreased in all of the participants at the immediate F/U. All participants in the intermediate-intensity treatment group showed a > 30% tumor size decrease, partial response, and a significant decrease in the CA 19-9 level at 3-month F/U and longer survival (p < 0.05). CONCLUSION: FUS with an intensity of 1.5 to 2.5 kW/cm2 was safe in the combined treatment of FUS and nPac/Gem. Considering the results of the change in tumor size, the change in CA 19-9 level, tumor response, and survival, these FUS parameters can be used for subsequent clinical trials. KEY POINTS: • No adverse device effect or dose-limiting toxicity occurred in any of the participants when focused ultrasound with an intensity of 1.5-2.5 kW/cm2 and a low duty cycle of 1% was combined with chemotherapy. • The intermediate-intensity group showed a >30% tumor size decrease, partial response, and a significant decrease in CA 19-9 in all of the participants at the 3-month follow-up and the longest survival. • Any focused ultrasound setting used in this study could be safe and optimal for subsequent clinical trials.

Online Learning versus Hands-On Learning of Basic Ocular Ultrasound Skills: A Randomized Controlled Non-Inferiority Trial.

Background and objectives: Ocular ultrasound is a core application of point-of-care ultrasound (POCUS) to assist physicians in promptly identifying various ocular diseases at the bedside; however, hands-on POCUS training is challenging during a pandemic. Materials and Methods: A randomized controlled non-inferiority trial was conducted in an academic emergency department from October 2020 to April 2021. Thirty-two participants were randomly assigned to one of two groups. Group H (hands-on learning group) participated individually in a hands-on session with a standardized patient for 30 min, whereas Group O (online learning group) learned training materials and video clips for 20 min. They scanned four eyeballs of two standardized patients sequentially following the ocular POCUS scan protocol. Repeated POCUS scans were performed 2 weeks later to assess skill maintenance. Both groups completed the pre- and post-surveys and knowledge tests. Two emergency medicine faculty members blindly evaluated the data and assigned a score of 0−25. The primary endpoint was the initial total score of scan quality evaluated using non-inferiority analysis (generalized estimating equation). The secondary endpoints were total scores for scan quality after 2 weeks, scan time, and knowledge test scores. Results: The least squares means of the total scores were 21.7 (0.35) for Group O and 21.3 (0.25) for Group H, and the lower bound of the 95% confidence interval (CI) was greater than the non-inferiority margin of minus 2 (95% CI: −0.48−1.17). The second scan scores were not significantly different from those of the first scan. The groups did not differ in scanning time or knowledge test results; however, Group H showed higher subjective satisfaction with the training method (p < 0.001). Conclusion: This study showed that basic online ocular ultrasound education was not inferior to hands-on education, suggesting that it could be a useful educational approach in the pandemic era.

Point-of-care ultrasound compression of the carotid artery for pulse determination in cardiopulmonary resuscitation.

AIM: To identify whether a novel pulse check technique, carotid artery compression using an ultrasound probe, can reduce pulse check times compared to manual palpation (MP). METHODS: This prospective study was conducted in an emergency department between February and December 2021. A physician applied point-of-care ultrasound-carotid artery compression (POCUS-CAC) and assessed the carotid artery compressibility and pulsatility by probe compression during rhythm check time. Another clinician performed MP of the femoral artery. The primary outcome was the difference in the average time for pulse assessment between POCUS-CAC and MP. The secondary outcomes included the time difference in each pulse check between methods, the proportion of times greater than 5 s and 10 s, and the prediction of return of spontaneous circulation (ROSC) during ongoing chest compression. RESULTS: 25 cardiac arrest patients and 155 pulse checks were analyzed. The median (interquartile range) average time to carotid pulse identification per patient using POCUS-CAC was 1.62 (1.14-2.14) s compared to 3.50 (2.99-4.99) s with MP. In all 155 pulse checks, the POCUS-CAC time to determine ROSC was significantly shortened to 0.44 times the MP time (P < 0.001). The POCUS-CAC approach never exceeded 10 s, and the number of patients who required more than 5 s was significantly lower (5 vs. 37, P < 0.001). Under continuous chest compression, six pulse checks predicted the ROSC. CONCLUSIONS: We found that emergency physicians could quickly determine pulses by applying simple POCUS compression of the carotid artery in cardiac arrest patients.

Establishment of ion channel and ABC transporter assays in 3D-cultured ReNcell VM on a 384-pillar plate for neurotoxicity potential.

Neurotoxicity potential of compounds by inhibition of ion channels and efflux transporters has been studied traditionally using two-dimensionally (2D) cultured cell lines such as CHO and HEK-293 overexpressing the protein of interest. However, these approaches are time consuming and do not recapitulate the activity of ion channels and efflux transporters indigenously expressed in neural stem cells (NSCs) in vivo. To overcome these issues, we established ion channel and transporter assays on a 384-pillar plate with three-dimensionally (3D) cultured ReNcell VM and demonstrated high-throughput measurement of ion channel and transporter activity. RNA sequencing analysis identified major ion channels and efflux transporters expressed in ReNcell VM, followed by validating 3D ReNcell-based ion channel and transporter assays with model compounds. Major ion channel activities were measured by specifically inhibiting potassium channels Kv 7.2 with XE-991 and Kv 4.3 with fluoxetine, and a calcium channel with 2-APB. Activities of major efflux transporters, MDR1, MRP1, and BCRP, were assessed using their respective blockers, verapamil, probenecid, and novobiocin. From this study, we demonstrated that 3D-cultured ReNcell VM on the 384-pillar plate could be a good alternative to rapidly identify environmental chemicals and therapeutic compounds for their role in modulating the activity of ion channels and efflux transporters, potentially leading to neurotoxicity.

Use of Gallbladder Width Measurement by Computed Tomography in the Diagnosis of Acute Cholecystitis.

This study aimed to evaluate the diagnostic value of gallbladder width measurement with computed tomography (CT) in patients with acute cholecystitis. This retrospective case−control study was conducted between March 2016 and March 2020 at a tertiary emergency department. Of 310 patients, 254 patients with acute cholecystitis confirmed by surgery were compared with 254 patients diagnosed with other diseases (controls). In the acute cholecystitis group, the number of older patients with underlying illnesses was much higher (64% of men). Upon CT, the median (interquartile range [IQR]) gallbladder width was significantly longer in patients with acute cholecystitis (2.26 [1.82−2.78] cm vs. 3.73 [3.32−4.16] cm, p < 0.001). The optimal cut-off value of gallbladder width for differentiating acute cholecystitis was 3.12 cm, showing a sensitivity of 88% and specificity of 86%. In a multivariable analysis using a logistic regression model for diagnosing acute cholecystitis with CT findings (gallbladder width, length, stone, wall thickening, and pericholecystic fluid), a gallbladder width of ≥3.12 cm was significantly meaningful, even when adjusting for other variables (odds ratio 37.9; p < 0.001). Therefore, an increase in gallbladder width (≥3.12 cm) measured with CT can be a simple and sensitive diagnostic sign of acute cholecystitis, supporting the underlying pathophysiology of bile outflow obstruction.

Echocardiographic Assessment of Patients with Pulmonary Tumor Thrombotic Microangiopathy First Diagnosed in the Emergency Department.

Pulmonary tumor thrombotic microangiopathy (PTTM) is a fatal disease that obstructs pulmonary vessels, leading to pulmonary hypertension (PH) and right-sided heart failure causing rapid progressive dyspnea in patients with cancer. This retrospective chart review involved nine patients with PTTM who were first clinically diagnosed in a tertiary emergency department (ED) between January 2015 and June 2021. They underwent laboratory tests, chest radiography, chest computed tomography (CT), and echocardiography. All patients presented with severe and rapidly progressive dyspnea within a few days, a high oxygen demand. The right ventricle (RV): left ventricle ratio was >1 on chest CT, and no life-threatening pulmonary thromboembolism (PTE) was observed. Echocardiographic findings indicated that all patients had moderate-to-severe RV dilatation with a D-shaped LV. The median tricuspid regurgitation maximum velocity was 3.8 m/s, and the median RV systolic pressure was 63 mmHg, indicating severe PH. The median value of tricuspid annular plane systolic excursion was 15 mm, showing a decrease in RV systolic function, and McConnell's sign was observed in five patients. Two patients immediately underwent chemotherapy and are currently alive. PTTM should be suspected and evaluated using echocardiography in patients with cancer presenting to the ED with acute dyspnea and RV failure without PTE.

Impact of Insurance Benefits and Education on Point-of-Care Ultrasound Use in a Single Emergency Department: An Interrupted Time Series Analysis.

Background and Objectives: Point-of-care ultrasound (POCUS) is a useful tool that helps clinicians properly treat patients in emergency department (ED). This study aimed to evaluate the impact of specific interventions on the use of POCUS in the ED. Materials and Methods: This retrospective study used an interrupted time series analysis to assess how interventions changed the use of POCUS in the emergency department of a tertiary medical institute in South Korea from October 2016 to February 2021. We chose two main interventions-expansion of benefit coverage of the National Health Insurance (NHI) for emergency ultrasound (EUS) and annual ultrasound educational workshops. The primary variable was the EUS rate, defined as the number of EUS scans per 1000 eligible patients per month. We compared the level and slope of EUS rates before and after interventions. Results: A total of 5188 scanned records were included. Before interventions, the EUS rate had increased gradually. After interventions, except for the first workshop, the EUS rate immediately increased significantly (p < 0.05). The difference in the EUS rate according to the expansion of the NHI was estimated to be the largest (p < 0.001). However, the change in slope significantly decreased after the third workshop during the coronavirus disease 2019 pandemic (p = 0.004). The EUS rate increased significantly in the presence of physicians participating in intensive POCUS training (p < 0.001). Conclusion: This study found that expansion of insurance coverage for EUS and ultrasound education led to a significant and immediate increase in the use of POCUS, suggesting that POCUS use can be increased by improving education and insurance benefits.

The effect of norepinephrine on common carotid artery blood flow in septic shock patients.

This study was designed to evaluate the hemodynamic effect of norepinephrine (NE) on the peak systolic velocity (PSV), diameter, and blood flow of the common carotid artery (CCA) using the point-of-care ultrasound (POCUS) in patients with septic shock. The study involved patients above 18 years old with septic shock. Arterial monitoring, carotid ultrasonography, and transthoracic echocardiography were performed before NE administration (T0). When the mean arterial pressure exceeded 65 mmHg after NE administration (T1), the measurement was repeated. Twenty-four patients (median age 67 [interquartile range: 54-77] years; 42% female) with septic shock were examined in this study. Before (T0) and after (T1) NE administration, the PSV (mean, standard deviation [SD]) changed from 85.3 (21.1) cm/s to 83.5 (23.5) cm/s (p = 0.417); this change was not significant. However, the diameter and blood flow of the CCA increased significantly from 0.6 (0.09) cm and 0.75 (0.27) L/min to 0.66 (0.09) cm and 0.85 (0.27) L/min, respectively (p < 0.001). The diameter of the left ventricular outflow tract (LVOT) remained unchanged, but the velocity time integral of the LVOT increased significantly from 21.7 (4.39) cm to 23.6 (5.14) cm. There was no significant correlation between changes in blood flow of the CCA and changes in cardiac output (coefficient -0.365, p = 0.079). In conclusion, NE increased the diameter and blood flow of the CCA significantly, without changing the PSV in patients with septic shock.

Respiratory Protection Effect of Ear-loop-type KF94 Masks according to the Wearing Method in COVID-19 Pandemic: a Randomized, Open-label Study.

BACKGROUND: Ear-loop-type Korean Filter 94 masks (KF94 masks, equivalent to the N95 and FFP2) are broadly used in health care settings in Korea for the coronavirus disease 2019 pandemic. METHODS: A prospective randomized open-label study was designed to identify differences in the fitting performance between mask wearing methods in three different types of KF94 mask with ear loops between January to March 2021. General-fitting involved wearing an ear-loop-type KF94 mask, and tight-fitting involved wearing a mask aided by a clip connecting the ear loops. Each of the 30 participants wore three types of masks according to a randomly assigned order in both methods and performed a total of six quantitative fit tests (QNFTs) according to the occupational safety and health administration protocol. RESULTS: All fit factors (FFs) measured by the QNFT were significantly higher for tight-fitting method with the clip in all KF94 masks (P < 0.001). However, the total FFs were very low, with a median (interquartile range) of 6 (3-23) and 29 (9-116) for general-fitting and tight-fitting, respectively. When wearing tightly, the horizontal 3-fold type mask with adjustable ear-loop length had the highest FF, with a median of 125, and the QNFT pass rate (FF ≥ 100) increased significantly from 4 (13%) to 18 (60%). CONCLUSION: Even with sufficient filter efficiency, ear-loop-type-KF94 masks do not provide adequate protection. However, in relatively low-risk environments, wearing a face-seal adjustable KF94 mask and tight wearing with a clip can improve respiratory protection for healthcare workers. TRIAL REGISTRATION: ClinicalTrials.gov Identifier: NCT04794556.