MassCode Liquid Arrays as a Tool for Multiplexed High-Throughput Genetic Profiling

Multiplexed detection assays that analyze a modest number of nucleic acid targets over large sample sets are emerging as the preferred testing approach in such applications as routine pathogen typing, outbreak monitoring, and diagnostics. However, very few DNA testing platforms have proven to offer a solution for mid-plexed analysis that is high-throughput, sensitive, and with a low cost per test. In this work, an enhanced genotyping method based on MassCode technology was devised and integrated as part of a high-throughput mid-plexing analytical system that facilitates robust qualitative differential detection of DNA targets. Samples are first analyzed using MassCode PCR (MC-PCR) performed with an array of primer sets encoded with unique mass tags. Lambda exonuclease and an array of MassCode probes are then contacted with MC-PCR products for further interrogation and target sequences are specifically identified. Primer and probe hybridizations occur in homogeneous solution, a clear advantage over micro- or nanoparticle suspension arrays. The two cognate tags coupled to resultant MassCode hybrids are detected in an automated process using a benchtop single quadrupole mass spectrometer. The prospective value of using MassCode probe arrays for multiplexed bioanalysis was demonstrated after developing a 14plex proof of concept assay designed to subtype a select panel of Salmonella enterica serogroups and serovars. This MassCode system is very flexible and test panels can be customized to include more, less, or different markers

Analysis of Patients with Ventricular Assist Devices Presenting to an Urban Emergency Department

Introduction: Left ventricular assist device (LVAD) insertion is an increasingly common intervention for patients with advanced heart failure; however, published literature on the emergency department (ED) presentation of this population is limited. The objective of this study was to characterize ED presentations of patients with LVADs with a focus on device-specific complications to inform provider education and preparation initiatives. Methods: This was a retrospective chart review of all patients with LVADs followed at an urban academic medical center presenting to the ED over a five-year period (July 1, 2009, to June 30, 2014). Two abstractors reviewed 45 randomly selected charts to standardize the abstraction process and establish a priori categories for reason for presentation to the ED. Remaining charts were then divided evenly for review by one of the two abstractors. Primary outcomes for this study were (1) frequency of and (2) reason for presentation to the ED by patients with LVADs. Results: Of 349 patients with LVADs identified, 143 (41.0%) had ED encounters during the study period. There were 620 total ED encounters, (range 1 to 32 encounters per patient, median=3, standard deviation=5.3). Among the encounters, 431 (69.5%) resulted in admission. The most common reasons for presentation were bleeding (e.g., gastrointestinal, epistaxis) (182, 29.4%); infection (127, 20.5%); heart failure exacerbation (68, 11.0%); pain (56, 9.0%); other (45, 7.3%); and arrhythmias (40, 6.5%). Fifty-two encounters (8.4%) were device-specific; these patients frequently presented with abnormal device readings (37, 6.0%). Interventions for device-specific presentations included anticoagulation regimen adjustment (16/52, 30.8%), pump exchange (9, 17.3%), and hardware repair (6, 11.5%). Pump thrombosis occurred in 23 cases (3.7% of all encounters). No patients required cardiopulmonary resuscitation or died in the ED. Conclusion: This is the largest study known to the investigators to report the rate of ED presentations of patients with LVADs and provide analysis of device-specific presentations. In patients who do have device-specific ED presentations, pump thrombosis is a common diagnosis and can present without device alarms. Specialized LVAD education and preparation initiatives for ED providers should emphasize the recognition and management of the most common and critical conditions for this patient population, which have been identified in this study as bleeding, infection, heart failure, and pump thrombosis

Analysis of Patients with Ventricular Assist Devices Presenting to an Urban Emergency Department

Introduction: Left ventricular assist device (LVAD) insertion is an increasingly common intervention for patients with advanced heart failure; however, published literature on the emergency department (ED) presentation of this population is limited. The objective of this study was to characterize ED presentations of patients with LVADs with a focus on device-specific complications to inform provider education and preparation initiatives. Methods: This was a retrospective chart review of all patients with LVADs followed at an urban academic medical center presenting to the ED over a five-year period (July 1, 2009, to June 30, 2014). Two abstractors reviewed 45 randomly selected charts to standardize the abstraction process and establish a priori categories for reason for presentation to the ED. Remaining charts were then divided evenly for review by one of the two abstractors. Primary outcomes for this study were (1) frequency of and (2) reason for presentation to the ED by patients with LVADs. Results: Of 349 patients with LVADs identified, 143 (41.0%) had ED encounters during the study period. There were 620 total ED encounters, (range 1 to 32 encounters per patient, median=3, standard deviation=5.3). Among the encounters, 431 (69.5%) resulted in admission. The most common reasons for presentation were bleeding (e.g., gastrointestinal, epistaxis) (182, 29.4%); infection (127, 20.5%); heart failure exacerbation (68, 11.0%); pain (56, 9.0%); other (45, 7.3%); and arrhythmias (40, 6.5%). Fifty-two encounters (8.4%) were device-specific; these patients frequently presented with abnormal device readings (37, 6.0%). Interventions for device-specific presentations included anticoagulation regimen adjustment (16/52, 30.8%), pump exchange (9, 17.3%), and hardware repair (6, 11.5%). Pump thrombosis occurred in 23 cases (3.7% of all encounters). No patients required cardiopulmonary resuscitation or died in the ED. Conclusion: This is the largest study known to the investigators to report the rate of ED presentations of patients with LVADs and provide analysis of device-specific presentations. In patients who do have device-specific ED presentations, pump thrombosis is a common diagnosis and can present without device alarms. Specialized LVAD education and preparation initiatives for ED providers should emphasize the recognition and management of the most common and critical conditions for this patient population, which have been identified in this study as bleeding, infection, heart failure, and pump thrombosis.

Objective Evaluation of a Didactic Curriculum for the Radiation Oncology Medical Student Clerkship

A structured didactic radiation oncology clerkship curriculum for medical students is in use at multiple academic medical centers. Objective evidence supporting this educational approach over the traditional clerkship model is lacking. This study evaluated the curriculum efficacy using an objective knowledge assessment. Medical students received the Radiation Oncology Education Collaborative Study Group (ROECSG) curriculum consisting of 3 lectures (Overview of Radiation Oncology, Radiation Biology/Physics, and Practical Aspects of Simulation/Radiation Emergencies) and a radiation oncology treatment-planning workshop. A standardized 20-item multiple choice question (MCQ) knowledge assessment was completed pre- and post-curriculum and approximately 6 months after receiving the curriculum. One hundred forty-six students at 22 academic medical centers completed the ROECSG curriculum from July to November 2016. One hundred nine students completed pre- and post-clerkship MCQ knowledge assessments (response rate 74.7%). Twenty-four students reported a prior rotation at a ROECSG institution and were excluded from analysis. Mean assessment scores increased from pre- to post-curriculum (63.9% vs 80.2%, P < .01). Mean MCQ knowledge subdomain assessment scores all improved post-curriculum (t test, P values < .01). Post-scores for students rotating de novo at ROECSG institutions (n = 30) were higher compared with pre-scores for students with ≥1 prior rotations at non-ROECSG institutions (n = 55) (77.3% vs 68.8%, P = .01), with an effect size of 0.8. Students who completed rotations at ROECSG institutions continued to demonstrate a trend toward improved performance on the objective knowledge assessment at approximately 6 months after curriculum exposure (70.5% vs 65.6%, P = .11). Objective evaluation of a structured didactic curriculum for the radiation oncology clerkship at early and late time points demonstrated significant improvement in radiation oncology knowledge. Students who completed clerkships at ROECSG institutions performed objectively better than students who completed clerkships at non-ROECSG institutions. These results support including a structured didactic curriculum as a standard component of the radiation oncology clerkship