Analytical Validation of a DNA Methylation Biomarker Test for the Diagnosis of Barrett's Esophagus and Esophageal Adenocarcinoma from Samples Collected Using EsoCheck®, a Non-Endoscopic Esophageal Cell Collection Device.

Barrett's esophagus (BE) is a known precursor to esophageal adenocarcinoma (EAC). Guidelines recommend BE screening in populations with multiple risk factors, for which non-endoscopic esophageal cell collection with biomarker testing is considered as an acceptable alternative to esophagogastroduodenoscopy (EGD). The aim of this study was to evaluate analytical performance characteristics of EsoGuard® (EG), a DNA methylation biomarker assay, as a laboratory-developed test (LDT) in esophageal samples collected with the swallowable EsoCheck® (EC) device. EG is a next-generation sequencing (NGS) assay that evaluates methylated vimentin (VIM) and cyclin A1 (CCNA1), clinically validated biomarkers for the detection of BE and EAC. The studies were conducted according to standards of College of American Pathology (CAP), Clinical Laboratory Improvement Amendments (CLIA), and New York (NY) state requirements for the analytical validation of molecular assays. Comparison to Sanger sequencing showed that EG was 100% accurate at all 31 CpG sites evaluated by the assay. The analytical sensitivity, specificity, and accuracy of the assay were 89%, 100%, and 96%, respectively. Intra- and inter-assay precision was 100%. The limit of detection (LOD) was 1 in 400 methylated cells, and the reference range was 84%. In summary, EsoGuard demonstrates high analytical accuracy, repeatability, and reproducibility in samples collected using the EsoCheck device.

Predicting surgical skill acquisition in preclinical medical students.

BACKGROUND: The purpose of this study was to identify factors that predict medical student success in acquiring invasive procedural skills. We hypothesized that students with interest in surgery and with prior procedural experience would have higher rates of success. METHODS: Preclinical students were enrolled in a simulation course comprised of suturing, intubation, and central venous catheterization. Students completed surveys to describe demographics, specialty interest area, prior experience, and confidence. Using linear regression, variables predictive of proficiency were identified. RESULTS: Forty-five participants completed the course. Under univariate analysis, composite pretest score was inversely associated with confidence (P = .039). Under multivariable analysis, female gender was associated with higher pretest suturing score (P = .016). Male gender (P = .029) and high confidence (P = .021) were associated with greater improvement in suturing. CONCLUSIONS: Among novices, higher confidence can predict lower baseline technical proficiency. Although females had higher pretest suturing scores, high confidence and male gender were associated with the greatest degree of improvement.

Adaptive simulation training using cumulative sum: a randomized prospective trial.

BACKGROUND: Cumulative sum (Cusum) is a novel tool that can facilitate adaptive, individualized training curricula. The purpose of this study was to use Cusum to streamline simulation-based training. METHODS: Preclinical medical students were randomized to Cusum or control arms and practiced suturing, intubation, and central venous catheterization in simulation. Control participants practiced between 8 and 9 hours each. Cusum participants practiced until Cusum proficient in all tasks. Group comparisons of blinded post-test evaluations were performed using Wilcoxon rank sum. RESULTS: Forty-eight participants completed the study. Average post-test composite score was 92.1% for Cusum and 93.5% for control (P = .71). Cusum participants practiced 19% fewer hours than control group participants (7.12 vs 8.75 hours, P < .001). Cusum detected proficiency relapses during practice among 7 (29%) participants for suturing and 10 (40%) for intubation. CONCLUSIONS: In this comparison between adaptive and volume-based curricula in surgical training, Cusum promoted more efficient time utilization while maintaining excellent results.

Vessel ligation training via an adaptive simulation curriculum.

BACKGROUND: A cost-effective model for open vessel ligation is currently lacking. We hypothesized that a novel, inexpensive vessel ligation simulator can efficiently impart transferrable surgical skills to novice trainees. MATERIALS AND METHODS: VesselBox was designed to simulate vessel ligation using surgical gloves as surrogate vessels. Fourth-year medical students performed ligations using VesselBox and were evaluated by surgical faculty using the Objective Structured Assessments of Technical Skills global rating scale and a task-specific checklist. Subsequently, each student was trained using VesselBox in an adaptive practice session guided by cumulative sum. Posttesting was performed on fresh human cadavers by evaluators blinded to pretest results. RESULTS: Sixteen students completed the study. VesselBox practice sessions averaged 21.8 min per participant (interquartile range 19.5-27.7). Blinded posttests demonstrated increased proficiency, as measured by both Objective Structured Assessments of Technical Skills (3.23 versus 2.29, P < 0.001) and checklist metrics (7.33 versus 4.83, P < 0.001). Median speed improved from 128.2 s to 97.5 s per vessel ligated (P = 0.001). After this adaptive training protocol, practice volume was not associated with posttest performance. CONCLUSIONS: VesselBox is a cost-effective, low-fidelity vessel ligation model suitable for graduating medical students and junior residents. Cumulative sum can facilitate an adaptive, individualized curriculum for simulation training.

Construct validation of a cost-effective vessel ligation benchtop simulator.

OBJECTIVE: Many benchtop surgical simulators assess laparoscopic proficiency, yet few address core open surgical skills. The purpose of this study is to describe a cost-effective benchtop vessel ligation simulator and provide construct validation. DESIGN: A prospective comparison of blinded proficiency assessments among participants performing a benchtop vessel ligation simulation task. Evaluations were performed using Objective Structured Assessments of Technical Skills. SETTING: This study took place at the University of Virginia, School of Medicine: a large academic medical institution. PARTICIPANTS: The participants included fourth-year medical students participating in a focused surgical elective course (n = 16), postgraduate year 2 to 3 surgery residents (n = 6), and surgical faculty (n = 5). RESULTS: The total fixed costs of the vessel ligation simulator was $30. Flexible costs of operation were less than $0.20 per attempt. The median task-specific checklist scores among the medical students, residents, and faculty were 4.83, 7.33, and 7.67, respectively. Median global rating scores across the 3 groups were 2.29, 4.43, and 4.76, respectively. Significant proficiency differences were noted between the students and the residents/faculty for both the metrics (p < 0.001). CONCLUSIONS: A cost-effective benchtop simulator can effectively measure proficiency with basic open surgical techniques such as vessel ligation. Among the junior surgical trainees, this tool can identify learning gaps and improve operative skills in a preclinical setting.

Assistant instructors facilitate simulation for medical students.

BACKGROUND: A procedural training protocol for medical students must be cognizant of faculty opportunity costs, which may preclude individually supervised practice. Meanwhile, sporadic exposure in large group settings yields suboptimal proficiency. The purpose of this study is to assess the effectiveness of undergraduate assistant instructors in providing one-on-one simulation-based instruction for basic invasive techniques. MATERIALS AND METHODS: Investigators designed proficiency-based checklists by faculty consensus for three simulation tasks as follows: orotracheal intubation, central venous catheterization, and suturing. Four undergraduate students were trained as instructors. Interrater agreement between instructors using the task checklists ranged from 0.754-0.866. Instructors conducted up to seven flexibly scheduled, one-on-one practice sessions with clinically inexperienced medical student participants. Sessions comprised repetitive task attempts with an evaluation after every attempt. On completion of the training protocol, participants underwent evaluation by an experienced surgeon blinded to practice session performance. Study participants were surveyed to assess satisfaction. RESULTS: Twenty-nine participants completed the study. Median total practice time was 8.75 h (interquartile range 7.12-8.75). Posttest pass rates were 93% (26/28), 71% (20/28), and 68% (19/28) for suturing, intubation, and central venous catheterization, respectively. Ninety-seven percent (27/28) of participants were satisfied with their experience, and 62% (18/29) advocated for protocol adoption into the standard preclinical curriculum. Estimated cost saved using student instructors, based on departmental collections for surgical faculty, was $43,760. CONCLUSIONS: Clinically inexperienced assistants may be trained as instructors for basic simulation tasks with excellent interrater reliability. Deploying these assistant instructors makes effective, one-on-one technical training for preclinical medical students financially feasible.

Verification of accurate technical insight: a prerequisite for self-directed surgical training.

Simulation-based surgical skills training during preclinical education is a persistent challenge due to time constraints of trainees and instructors alike. Self-directed practice is resource-efficient and flexible; however, insight into technical proficiency among trainees is often lacking. The purpose of this study is to prospectively assess the accuracy of self-assessments among medical students learning basic surgical suturing. Over seven weekly practice sessions, preclinical medical students performed serial repetitions of a simulation-based suturing task under one-on-one observation by one of four trainers. Following each task repetition, self- and trainer-assessments (SA-TA) were performed using a 36-point weighted checklist of technical standards developed a priori by expert consensus. Upon study completion, agreement between SA and TA was measured using weighted Cohen's kappa coefficients. Twenty-nine medical students each performed a median of 25 suture task repetitions (IQR 21.5-28). Self-assessments tended to overestimate proficiency during the first tertile of practice attempts. Agreement between SA and TA improved with experience, such that the weighted kappa statistics for the two-handed and instrument ties were >0.81 after 18-21 task attempts. Inexperienced trainees frequently overestimate technical proficiency through self-assessments. However, this bias diminishes with repetitive practice. Only after trainees have attained the capacity to accurately self-assess can effective self-directed learning take place.

The effect of auditory and visual distracters on the useful field of view: implications for the driving task.

PURPOSE: The driving environment is becoming increasingly complex, including both visual and auditory distractions within the in-vehicle and external driving environments. This study was designed to investigate the effect of visual and auditory distractions on a performance measure that has been shown to be related to driving safety, the useful field of view. METHODS: A laboratory study recorded the useful field of view in 28 young visually normal adults (mean 22.6 +/- 2.2 years). The useful field of view was measured in the presence and absence of visual distracters (of the same angular subtense as the target) and with three levels of auditory distraction (none, listening only, listening and responding). RESULTS: Central errors increased significantly (P < 0.05) in the presence of auditory but not visual distracters, while peripheral errors increased in the presence of both visual and auditory distracters. Peripheral errors increased with eccentricity and were greatest in the inferior region in the presence of distracters. CONCLUSIONS: Visual and auditory distracters reduce the extent of the useful field of view, and these effects are exacerbated in inferior and peripheral locations. This result has significant ramifications for road safety in an increasingly complex in-vehicle and driving environment.