William Dixon

All Publications

• Mastery Learning Improves Simulated Distal Radius Fracture Management by Emergency Medicine Teaching Faculty. Simulation in healthcare : journal of the Society for Simulation in Healthcare Pokrajac, N., Gisondi, M. A., Jensen, A., Roszczynialski, K. N., Preiksaitis, C., Dixon, W. 2025

  Abstract

  Emergency medicine (EM) physicians must be competent in managing distal radius fractures, yet training gaps exist. This study evaluated academic EM physician proficiency in managing a simulated distal radius fracture and the impact of a simulation-based mastery learning (SBML) intervention.We conducted a pretest-posttest study of board-certified or board-eligible EM physicians at a university-based training hospital between August and December 2023. Four trained facilitators assessed participants on distal radius fracture management using a task trainer and a 41-item checklist with a minimum passing standard (MPS) of 37/41 (90.2%). The SBML intervention included baseline assessment, individualized feedback, deliberate practice, and reassessment.Fifty-one physicians participated in the pretest, with a median score of 32/41 (78.0%) and 10 (19.6%) achieving the MPS initially. Of the 20 participants who completed the posttest, 19 (95%) achieved the MPS after SBML intervention. The intervention resulted in a significant mean score improvement of 8.4 points (95% confidence interval: 6.92-9.78; P < 0.01). Only performing a distal radius fracture reduction in the past year significantly predicted higher pretest performance (3.3 points higher, P = 0.04). Participant comfort with all aspects of distal radius fracture management significantly improved after SBML.Academic EM physicians demonstrated performance gaps in distal radius fracture management that were effectively addressed by SBML. Few clinical experience metrics predicted performance, suggesting a need for targeted educational interventions to maintain skills in this important procedural area.

  View details for DOI 10.1097/SIH.0000000000000902

  View details for PubMedID 41427620

• Quantifying Emergency Medicine Residency Learning Curves Using Natural Language Processing: Retrospective Cohort Study. JMIR medical education Preiksaitis, C., Hughes, J., Kabeer, R., Dixon, W., Rose, C. 2025; 11: e82326

  Abstract

  The optimal duration of emergency medicine (EM) residency training remains a subject of national debate, with the Accreditation Council for Graduate Medical Education considering standardizing all programs to 4 years. However, empirical data on how residents accumulate clinical exposure over time are limited. Traditional measures, such as case logs and diagnostic codes, often fail to capture the breadth and depth of diagnostic reasoning. Natural language processing (NLP) of clinical documentation offers a novel approach to quantifying clinical experiences more comprehensively.This study aimed to (1) quantify how EM residents acquire clinical topic exposure over the course of training, (2) evaluate variation in exposure patterns across residents and classes, and (3) assess changes in workload and case complexity over time to inform the discussion on optimal program length.We conducted a retrospective cohort study of EM residents at Stanford Hospital, analyzing 244,255 emergency department encounters from July 1, 2016, to November 30, 2023. The sample included 62 residents across 4 graduating classes (2020-2023), representing all primary training site encounters where residents served as primary or supervisory providers. Using a retrieval-augmented generation NLP pipeline, we mapped resident clinical documentation to the 895 subcategories of the 2022 Model for Clinical Practice of Emergency Medicine (MCPEM) via intermediate mapping to the Systematized Nomenclature of Medicine, Clinical Terms, Clinical Observations, Recordings, and Encoding problem list subset. We generated cumulative topic exposure curves, quantified the diversity of topic coverage, assessed variability between residents, and analyzed the progression in clinical complexity using Emergency Severity Index (ESI) scores and admission rates.Residents encountered the largest increase in new topics during postgraduate year 1 (PGY1), averaging 376.7 (42.1%) unique topics among a total of 895 MCPEM subcategories. By PGY4, they averaged 565.9 (63.2%) topics, representing a 9.9% (51/515) increase over PGY3. Exposure plateaus generally occurred at 39 to 41 months, although substantial individual variation was observed, with some residents continuing to acquire new topics until graduation. Annual case volume more than tripled from PGY1 (mean 445.7, SD 112.7 encounters) to PGY4 (mean 1528.4, SD 112.7 encounters). Case complexity increased, as evidenced by a decrease in mean ESI score from 2.94 to 2.79, and a rise in high-acuity (ESI 1-2) cases from 16% (4374/27,340) to 30.9% (9418/30,466).NLP analysis of clinical documentation provides a scalable, detailed method for tracking EM residents' clinical exposure and progression. Many residents continue to gain new experiences into their fourth year, particularly in higher-acuity cases. These findings suggest that a 4-year training model may offer meaningful additional educational value, while also highlighting the importance of individualized assessment given the variability in learning trajectories.

  View details for DOI 10.2196/82326

  View details for PubMedID 41364786

• Use of Glucagon-Like Peptide-1 Agonists and Increased Risk of Procedural Sedation and Endotracheal Intubation in the Emergency Department. Annals of emergency medicine Dixon, W. 2024; 84 (2): 226-227

  View details for DOI 10.1016/j.annemergmed.2024.03.007

  View details for PubMedID 39032988

• The Influence of COVID on Emergency Medicine Career Choice: A Survey of Medical Students CUREUS JOURNAL OF MEDICAL SCIENCE Chandra, S., Olaf, M., Fix, M., Bord, S., Katirji, L., Dixon, W., Pasirstein, M., Schrepel, C., Scott, K. R. 2024; 16 (4): e59055

  Abstract

  Background The COVID-19 pandemic has led to substantial changes in the delivery of healthcare and medical education. Little is known about how the pandemic has altered medical students' perceptions in regard to career choice. Methods The authors developed and implemented a multi-center survey that evaluated medical students' preferred career choice before and during the coronavirus pandemic, as well as the influence of pandemic-related factors on that choice. The survey was distributed to all levels of medical students (MS) at nine medical schools across the country from November 2020 to January 2021 and represented a convenience sample. Preferred career choice was assessed through the use of a Likert scale and additional factors affecting career choice were solicited. The degree of interest before and during the pandemic, as well as factors influencing the shift, were treated as ordinal variables and compared using chi-squared testing. Cohen's Kappa statistic was calculated to assess the degree of shifts of interest in Emergency Medicine among students. The study was deemed exempt by the Institutional Review Board at the host institution, Sidney Kimmel Medical College at Thomas Jefferson University, and all participating sites. Results A total of 1431 of 6710 (21.3%) eligible students completed the survey. The COVID pandemic was cited as a reason for a changed interest in specialty by 193 (13.5%) students. The most common reason for specialty change was the students' clinical experience, followed by a desire to be on the front lines, and personal/family health concerns. There was a significant association between career change and degree of interest among students interested in emergency medicine (EM) as their future specialty before the COVID pandemic as well as during the COVID pandemic. Living with an immunocompromised individual had a significant association with a reduced interest in EM. There was a significant association between EM rotation completion and how interested students were in EM as their future specialty before the COVID pandemic and during the COVID pandemic. Among EM-interested students whose specialty interest was changed by the COVID pandemic, 34 (41.5%) became less favorable to EM, 28 (34.2%) stayed the same, and 20 (24.4%) students became more favorable to EM. Conclusions The impact of COVID-19 on medical students' career choice is a complicated matter that involves both personal and professional factors. It appears that there is a trend towards less interest in the field of EM with multifactorial influences, some of which are related to the COVID-19 pandemic.

  View details for DOI 10.7759/cureus.59055

  View details for Web of Science ID 001223440400007

  View details for PubMedID 38800319

  View details for PubMedCentralID PMC11128144

• Simulation-Based Mastery Learning Improves the Performance of Donning and Doffing of Personal Protective Equipment by Medical Students. The western journal of emergency medicine Miller, D. T., Pokrajac, N., Ngo, J., Gallegos, M., Dixon, W., Roszczynialski, K. N., Ng, K., Taleghani, N., Gisondi, M. A. 2022; 23 (3): 318-323

  Abstract

  Medical students lack adequate training on how to correctly don and doff personal protective equipment (PPE). Simulation-based mastery learning (SBML) is an effective technique for procedural education. The aim of this study was to determine whether SBML improves proper PPE donning and doffing by medical students.This was a prospective, pre-test/post-test study of 155 medical students on demonstration of correct PPE use before and after a SBML intervention. Subjects completed standard hospital training by viewing a US Centers for Disease Control and Prevention training video on proper PPE use prior to the intervention. They then participated in a SBML training session that included baseline testing, deliberate practice with expert feedback, and post-testing until mastery was achieved. Students were assessed using a previously developed 21-item checklist on donning and doffing PPE with a minimum passing standard (MPS) of 21/21 items. We analyzed differences between pre-test and post-test scores using paired t-tests. Students at preclinical and clinical levels of training were compared with an independent t-test.Two participants (1.3%) met the MPS on pre-test. Of the remaining 153 subjects who participated in the intervention, 151 (98.7%) reached mastery. Comparison of mean scores from pre-test to final post-test significantly improved from an average raw score of 12.55/21 (standard deviation [SD] = 2.86), to 21/21(SD = 0), t(150) = 36.3, P <0.001. There was no difference between pre-test scores of pre-clinical and clinical students.Simulation-based mastery learning improves medical student performance in PPE donning and doffing in a simulated environment. This approach standardizes PPE training for students in advance of clinical experiences.

  View details for DOI 10.5811/westjem.2022.2.54748

  View details for PubMedID 35679489

• A Brief Coaching Pilot Enhances Professional Identity Formation and Clinical Skills Acquisition During Emergency Medicine Clerkships Shortened by COVID-19. The western journal of emergency medicine Dixon, W., Gallegos, M., Williams, S. 1800; 23 (1): 30-32

  Abstract

  INTRODUCTION: The Covid-19 pandemic limited educational and career development opportunities for medical students, requiring innovative programs to accelerate professional identity formation and clinical skills acquisition.METHODS: We developed a brief coaching intervention that took place over the advanced (sub-internship) emergency medicine rotation at our institution. We trained coaches using a newly developed workshop, who met with students for an average of 4.5 hours over 3 weeks.IMPACT/EFFECTIVENESS: We showed that this coaching program was both feasible and impactful for faculty coaches and medical students.

  View details for DOI 10.5811/westjem.2021.12.53917

  View details for PubMedID 35060857

• A nationwide survey of emergency medicine resident workflow efficiency: Are training programs teaching residents to be efficient? AEM education and training Carmelli, G., Watson, E. E., Villarroel, N. A., Dixon, W. W., Clarke, S. O. 2021; 5 (2): e10598

  Abstract

  Background: Workflow efficiency (WFE) is essential to the practice of emergency medicine (EM), but a standardized approach to measuring and teaching it during residency is lacking. In this study we sought to describe how EM residency programs in the United States currently measure and teach WFE and to assess the relative importance of WFE teaching to EM residency program leaders.Methods: We conducted a cross-sectional survey of all accredited EM residency training programs in the United States in Fall 2019. We invited all allopathic EM residency programs to participate in the study by directly emailing program directors and assistant/associate program directors. We conducted the study and performed descriptive statistics using SurveyMonkey software.Results: We received a total of 133 responses out of 190 total programs (70%) with proportionate representation from 3- and 4-year programs and all regions of the United States. When asked to what extent teaching efficiency should be a priority compared to other educational goals, 65% of program leaders responded with "significant" or "moderate" priority. Most EM programs collect WFE data on their residents, either by tracking patients per hour (78%) or by written evaluations (59%). Common methods for providing WFE data to residents were: "individual data provided along with deidentified rank" (35%), "data provided only during private feedback meetings" (26%), and "no data or rank provided to residents" (16%). Regarding targeted WFE teaching to residents, 88% reported utilizing general on-shift teaching, 48% reported teaching WFE during formal didactics, and 45% during dedicated private feedback sessions.Conclusion: This national study of allopathic U.S. EM programs suggests that most EM program leaders do value WFE teaching. However, we found no consistent approach among programs for tracking or distributing resident WFE data, and many programs lack a formalized way to teach efficiency to their residents.

  View details for DOI 10.1002/aet2.10598

  View details for PubMedID 33969252

• Development of a 3D printed simulator for closed reduction of distal radius fractures. Perspectives on medical education Dixon, W. n., Miller, N. n., Toal, G. G., Sebok-Syer, S. S., Gisondi, M. A. 2020

  Abstract

  The use of simulators in medical education is critical for developing procedural competence prior to treating patients. Current training of emergency physicians to perform distal radius fracture reduction is inconsistent and inadequate.We developed a 3D printed distal radius fracture simulation training model that is easy to assemble and relatively inexpensive. We present step-by-step instructions to reproduce the model.The model was found to have high fidelity for training by both instructors and participants in a simulation-based mastery learning course.We successfully designed a low cost, easy to reproduce, high fidelity model for use in a simulation-based mastery learning course to teach distal radius fracture reduction.

  View details for DOI 10.1007/s40037-020-00609-w

  View details for PubMedID 32989709

• Simulation-Based Mastery Learning to Teach Distal Radius Fracture Reduction. Simulation in healthcare : journal of the Society for Simulation in Healthcare Toal, G. G., Gisondi, M. A., Miller, N. M., Sebok-Syer, S. S., Avedian, R. S., Dixon, W. W. 2020; Publish Ahead of Print

  Abstract

  Distal radius fractures are common orthopedic injuries managed in emergency departments. Simulation-based mastery learning is widely recognized to improve provider competence for bedside procedures but has not been studied to teach fracture management. This study evaluated the effectiveness of a simulation-based mastery learning curriculum to teach distal radius fracture reduction to novice orthopedic surgery and emergency medicine residents.We created a novel mastery learning checklist using the Mastery Angoff method of standard setting, paired with a new simulation model designed for this project, to teach orthopedic surgery and emergency medicine interns (N = 22) at the study site. Orthopedic surgery and emergency medicine faculty members participated in checklist development, curriculum design, and implementation. Training included just-in-time asynchronous education with a readiness assessment test, in-classroom expert demonstration, and deliberate practice with feedback. Residents completed a pretest/posttest skills examination and a presurvey/postsurvey assessing procedural confidence.Standard setting resulted in a 41-item checklist with minimum passing score of 37/41 items. All participants met or surpassed the minimum passing score on postexamination. Postsurvey confidence levels were significantly higher than presurvey in all aspects of the distal radius fracture procedure (P < 0.05).This study demonstrated that a simulation-based mastery learning curriculum improved skills and confidence performing distal radius fracture reductions for orthopedic surgery and emergency medicine interns. Future planned studies include curriculum testing across additional institutions, examination of clinical impact, and application of mastery learning for other orthopedic procedures.

  View details for DOI 10.1097/SIH.0000000000000534

  View details for PubMedID 33337726

• The putative Poc complex controls two distinct Pseudomonas aeruginosa polar motility mechanisms MOLECULAR MICROBIOLOGY Cowles, K. N., Moser, T. S., Siryaporn, A., Nyakudarika, N., Dixon, W., Turner, J. J., Gitai, Z. 2013; 90 (5): 923-938

  Abstract

  Each Pseudomonas aeruginosa cell localizes two types of motility structures, a single flagellum and one or two clusters of type IV pili, to the cell poles. Previous studies suggested that these motility structures arrive at the pole through distinct mechanisms. Here we performed a swimming motility screen to identify polar flagellum localization factors and discovered three genes homologous to the TonB/ExbB/ExbD complex that have defects in both flagella-mediated swimming and pilus-mediated twitching motility. We found that deletion of tonB3, PA2983 or PA2982 led to non-polar localization of the flagellum and FlhF, which was thought to sit at the top of the flagellar localization hierarchy. Surprisingly, these mutants also exhibited pronounced changes in pilus formation or localization, indicating that these proteins may co-ordinate both the pilus and flagellum motility systems. Thus, we have renamed PA2983 and PA2982, pocA and pocB, respectively, for polar organelle co-ordinator to reflect this function. Our results suggest that TonB3, PocA and PocB may form a membrane-associated complex, which we term the Poc complex. These proteins do not exhibit polar localization themselves, but are required for increased expression of pilus genes upon surface association, indicating that they regulate motility structures through either localization or transcriptional mechanisms.

  View details for DOI 10.1111/mmi.12403

  View details for Web of Science ID 000327374300002

  View details for PubMedID 24102920

  View details for PubMedCentralID PMC4666538

• Multiplexed protein detection by proximity ligation for cancer biomarker validation NATURE METHODS Fredriksson, S., Dixon, W., Ji, H., Koong, A. C., Mindrinos, M., Davis, R. W. 2007; 4 (4): 327-329

  Abstract

  We present a proximity ligation-based multiplexed protein detection procedure in which several selected proteins can be detected via unique nucleic-acid identifiers and subsequently quantified by real-time PCR. The assay requires a 1-microl sample, has low-femtomolar sensitivity as well as five-log linear range and allows for modular multiplexing without cross-reactivity. The procedure can use a single polyclonal antibody batch for each target protein, simplifying affinity-reagent creation for new biomarker candidates.

  View details for DOI 10.1038/NMETH1020

  View details for Web of Science ID 000245584900013

  View details for PubMedID 17369836