Incidence and Risk Factors of Heterotopic Ossification in the Knee After Reamed Tibial Nailing.

INTRODUCTION: Heterotopic ossification (HO) in the knee after tibial intramedullary nailing (IMN) has yet to be thoroughly investigated. Our aim was to assess frequency and associated factors for HO in the knee after tibial IMN. METHODS: This is a retrospective review at a single level 1 urban trauma center of 213 patients who underwent reamed tibial IMN. Plain radiographs were reviewed postoperatively and on final follow-up (≥6 weeks). Chart review was performed for surgical approach (suprapatellar versus infrapatellar), demographics, injury characteristics, and clinical follow-up. The primary outcome was frequency of HO. RESULTS: HO on final follow-up (mean: 41.43 weeks) was recorded in 15% cases. Postsurgical retroinfrapatellar reaming debris (odds ratio [OR], 4.73), Injury Severity Score (OR, 1.05), intensive care unit admission (OR, 2.89), chest injury (OR, 3.4), and ipsilateral retrograde femoral IMN (OR, 5.08) showed a notable association with HO development. No association was observed in HO formation between surgical approach, knee pain, or range-of-motion deficits. DISCUSSION: Radiographic evidence of HO in the knee after reamed tibial IMN is not uncommon and is associated with retained reaming debris, Injury Severity Score, chest injury, intensive care unit admission, and ipsilateral retrograde femoral nailing. No differences were noted in HO formation between approaches. HO was not associated with knee pain or range-of-motion deficits.

Automated spatially targeted optical micro proteomics identifies fibroblast- and macrophage-specific regulation of myocardial infarction scar maturation in rats.

Myocardial infarction (MI) results from occlusion of blood supply to the heart muscle causing death of cardiac muscle cells. Following myocardial infarction (MI), extracellular matrix deposition and scar formation mechanically stabilize the injured heart as damaged myocytes undergo necrosis and removal. Fibroblasts and macrophages are key drivers of post-MI scar formation, maturation, and ongoing long-term remodelling; however, their individual contributions are difficult to assess from bulk analyses of infarct scar. Here, we employ state-of-the-art automated spatially targeted optical micro proteomics (autoSTOMP) to photochemically tag and isolate proteomes associated with subpopulations of fibroblasts (SMA+) and macrophages (CD68+) in the context of the native, MI tissue environment. Over a time course of 6-weeks post-MI, we captured dynamic changes in the whole-infarct proteome and determined that some of these protein composition signatures were differentially localized near SMA+ fibroblasts or CD68+ macrophages within the scar region. These results link specific cell populations to within-infarct protein remodelling and illustrate the distinct metabolic and structural processes underlying the observed physiology of each cell type.

Addressing Driving in Acute Care: Perceived Relevance and Competence.

Background. Recent legislation has expanded the responsibilities of occupational therapists regarding fitness to drive in the Canadian province of Ontario. To date, little is known about the practice of acute care occupational therapy with addressing driving, or how such responsibilities have affected clinical practice. Purpose. The objective of this study was to understand the relevance of driving-related knowledge areas to acute care occupational therapists and examine their self-reported competency for these areas. Method. Anonymous online surveys were administered to 41 occupational therapists working in acute care hospitals in Ontario. Findings. Therapists reported many driving-related knowledge areas are relevant to acute care practice yet consistently reported lower levels of competence for addressing such areas. Implications. Findings support the need for further competency development regarding driving-related practice in acute care. Occupational therapy curriculum and continuing education initiatives are avenues for capacity-building. Future research to identify effective competency development strategies is warranted.

Evaluating Note Frequency and Velocity During Improvised Active Music Therapy in Clients With Parkinson's Disease.

The purpose of this article was to report on the findings of the note frequency and velocity measures during Improvised Active Music Therapy (IAMT) sessions with individuals with Parkinson's disease (PD). In this single-subject multiple baseline design across subjects, the article reports the note frequency (note count) and velocity of movement (mean note velocity) played by three right-handed participants while playing uninterrupted improvised music on a simplified electronic drum-set. During baseline, the music therapist played rhythmic accompaniment on guitar using a low-moderate density of syncopation. During treatment, the Music Therapist introduced rhythms with a moderate-high density of syncopation. The music content of the sessions was transformed into digital music using a musical instrument digital interface. Results of this study indicated that all participants exhibited an increase in note count during baseline until reaching a plateau at treatment condition and were found to be significantly positively correlated with the Music Therapist's note count. All participants played more notes with upper extremity (UE) across conditions than with lower extremity. All participants also scored similar total mean velocity across conditions. Two participants demonstrated higher mean note velocity with UE than right foot, whereas the other participant did not demonstrate this difference. Two participants also exhibited greater mean note velocity variability with left foot within and across conditions. More research is required to identify commonalities in note count and mean note velocity measures in individuals with PD during IAMT sessions.

Machine learning for multidimensional response and survival after cardiac resynchronization therapy using features from cardiac magnetic resonance.

Background: Cardiac resynchronization therapy (CRT) response is complex, and better approaches are required to predict survival and need for advanced therapies. Objective: The objective was to use machine learning to characterize multidimensional CRT response and its relationship with long-term survival. Methods: Associations of 39 baseline features (including cardiac magnetic resonance [CMR] findings and clinical parameters such as glomerular filtration rate [GFR]) with a multidimensional CRT response vector (consisting of post-CRT left ventricular end-systolic volume index [LVESVI] fractional change, post-CRT B-type natriuretic peptide, and change in peak VO2) were evaluated. Machine learning generated response clusters, and cross-validation assessed associations of clusters with 4-year survival. Results: Among 200 patients (median age 67.4 years, 27.0% women) with CRT and CMR, associations with more than 1 response parameter were noted for the CMR CURE-SVD dyssynchrony parameter (associated with post-CRT brain natriuretic peptide [BNP] and LVESVI fractional change) and GFR (associated with peak VO2 and post-CRT BNP). Machine learning defined 3 response clusters: cluster 1 (n = 123, 90.2% survival [best]), cluster 2 (n = 45, 60.0% survival [intermediate]), and cluster 3 (n = 32, 34.4% survival [worst]). Adding the 6-month response cluster to baseline features improved the area under the receiver operating characteristic curve for 4-year survival from 0.78 to 0.86 (P = .02). A web-based application was developed for cluster determination in future patients. Conclusion: Machine learning characterizes distinct CRT response clusters influenced by CMR features, kidney function, and other factors. These clusters have a strong and additive influence on long-term survival relative to baseline features.

Cardiac magnetic resonance defines mechanisms of sex-based differences in outcomes following cardiac resynchronization therapy.

Background: Mechanisms of sex-based differences in outcomes following cardiac resynchronization therapy (CRT) are poorly understood. Objective: To use cardiac magnetic resonance (CMR) to define mechanisms of sex-based differences in outcomes after CRT and describe distinct CMR-based phenotypes of CRT candidates based on sex and non-ischemic/ischemic cardiomyopathy type. Materials and methods: In a prospective study, sex-based differences in three short-term CRT response measures [fractional change in left ventricular end-systolic volume index 6 months after CRT (LVESVI-FC), B-type natriuretic peptide (BNP) 6 months after CRT, change in peak VO2 6 months after CRT], and long-term survival were evaluated with respect to 39 baseline parameters from CMR, exercise testing, laboratory testing, electrocardiograms, comorbid conditions, and other sources. CMR was also used to quantify the degree of left-ventricular mechanical dyssynchrony by deriving the circumferential uniformity ratio estimate (CURE-SVD) parameter from displacement encoding with stimulated echoes (DENSE) strain imaging. Statistical methods included multivariable linear regression with evaluation of interaction effects associated with sex and cardiomyopathy type (ischemic and non-ischemic cardiomyopathy) and survival analysis. Results: Among 200 patients, the 54 female patients (27%) pre-CRT had a smaller CMR-based LVEDVI (p = 0.04), more mechanical dyssynchrony based on the validated CMR CURE-SVD parameter (p = 0.04), a lower frequency of both late gadolinium enhancement (LGE) and ischemic cardiomyopathy (p < 0.0001), a greater RVEF (p = 0.02), and a greater frequency of LBBB (p = 0.01). After categorization of patients into four groups based on cardiomyopathy type (ischemic/non-ischemic cardiomyopathy) and sex, female patients with non-ischemic cardiomyopathy had the lowest CURE-SVD (p = 0.003), the lowest pre-CRT BNP levels (p = 0.01), the lowest post-CRT BNP levels (p = 0.05), and the most favorable LVESVI-FC (p = 0.001). Overall, female patients had better 3-year survival before adjustment for cardiomyopathy type (p = 0.007, HR = 0.45) and after adjustment for cardiomyopathy type (p = 0.009, HR = 0.67). Conclusion: CMR identifies distinct phenotypes of female CRT patients with non-ischemic and ischemic cardiomyopathy relative to male patients stratified by cardiomyopathy type. The more favorable short-term response and long-term survival outcomes in female heart failure patients with CRT were associated with lower indexed CMR-based LV volumes, decreased presence of scar associated with prior myocardial infarction and ICM, and greater CMR-based dyssynchrony with the CURE-SVD.

Simulation-Based Outreach Program Improves Rural Hospitals' Team Confidence in Neonatal Resuscitation.

INTRODUCTION: Neonatal resuscitation is a high acuity, low occurrence event (HALO), and in rural community hospitals, low birth rates prevent providers from regular opportunities to maintain essential resuscitation skills. Simulation is an effective training modality for medical education, although resources for simulation are often limited in rural hospitals. Our primary objective was to test the hypothesis that in situ neonatal resuscitation simulation training improves rural hospitals' delivery room team confidence in performing key Neonatal Resuscitation Program® (NRP®) skills. Our secondary objective was to compare confidence to performance as measured by adherence to NRP® guidelines. METHODS: We conducted a quasi-experimental pre-training survey and post-training survey of delivery room team confidence in NRP® skills at five level one delivery hospitals before and after an in situ simulation training program. Participants included rural hospitals' usual delivery room team members. Participants rated their confidence on a five-point Likert scale. Simulations were analyzed using an adapted version of a validated scoring tool for NRP® adherence and presented as overall percentage scores. RESULTS: Our data demonstrate a significant improvement in self-assessed confidence levels pre- and post-simulation training in key areas of neonatal resuscitation. Participants reported higher confidence in airway management (4 vs. 3, p=0.003), emergency intravenous access (3 vs. 2, p=0.007), and the ability to manage a code in the delivery room (4 vs. 3, p=0.013) and the operating room (4 vs. 3, p=0.028). Improvements were also noted in their team member's knowledge and skills to perform neonatal resuscitation. While improvements were appreciated in confidence, the performance of skills (NRP® adherence scores) was often in the sub-optimal performance range. CONCLUSIONS: An in situ-based neonatal resuscitation outreach simulation program improves self-confidence among rural delivery room teams. Additional research is needed to understand how to translate improved confidence into actual improved performance.

Multiscale model of heart growth during pregnancy: integrating mechanical and hormonal signaling.

Pregnancy stands at the interface of mechanics and biology. The growing fetus continuously loads the maternal organs as circulating hormone levels surge, leading to significant changes in mechanical and hormonal cues during pregnancy. In response, maternal soft tissues undergo remarkable growth and remodeling to support the mother and baby for a healthy pregnancy. We focus on the maternal left ventricle, which increases its cardiac output and mass during pregnancy. This study develops a multiscale cardiac growth model for pregnancy to understand how mechanical and hormonal cues interact to drive this growth process. We coupled a cell signaling network model that predicts cell-level hypertrophy in response to hormones and stretch to a compartmental model of the rat heart and circulation that predicts organ-level growth in response to hemodynamic changes. We calibrated this multiscale model to data from experimental volume overload and hormonal infusions of angiotensin 2 (AngII), estrogen (E2), and progesterone (P4). We then validated the model's ability to capture interactions between inputs by comparing model predictions against published observations for the combinations of VO + E2 and AngII + E2. Finally, we simulated pregnancy-induced changes in hormones and hemodynamics to predict heart growth during pregnancy. Our model produced growth consistent with experimental data. Overall, our analysis suggests that the rise in P4 during the first half of gestation is an important contributor to heart growth during pregnancy. We conclude with suggestions for future experimental studies that will provide a better understanding of how hormonal and mechanical cues interact to drive pregnancy-induced heart growth.

Gait in younger and older adults during rhythmic auditory stimulation is influenced by groove, familiarity, beat perception, and synchronization demands.

Music-based Rhythmic auditory stimulation (RAS) is a cueing intervention used to regulate gait impairments in conditions such as Parkinson's disease or stroke. Desire to move with music ('groove') and familiarity have been shown to impact younger adult gait while walking with music, and these effects appear to be influenced by individual rhythmic ability. Importantly, these factors have not been examined in older adults. The aim of this study was to determine how gait outcomes during RAS are influenced by musical properties (familiarity, 'groove') in both free and synchronized walking for younger and older adults with good and poor beat perception ability. To do this, participants were randomized to either free or synchronized walking groups. Each participant's gait was assessed on a pressure sensitive walkway during high versus low groove and high versus low familiarity music, as well as metronome, cueing trials. Individual beat perception ability was evaluated using the Beat Alignment Test. Results showed that the effects of synchronization and groove were mostly consistent across age groups. High groove music elicited faster gait in both age groups, with longer strides only among young adults, than low groove music; synchronizing maximized these effects. Older adults with poor beat perception were more negatively affected by unfamiliar stimuli while walking than younger adults. This suggests that older adults, like younger adults, may benefit from synchronized RAS to high groove cues but may be more vulnerable to cognitive demands associated with walking to unfamiliar stimuli. This should be accounted for in clinical implementations of RAS.

Mobile-based brief interventions targeting cannabis-impaired driving among youth: A Delphi study.

INTRODUCTION: Brief interventions delivered using mobile technologies have become popular to reduce youth alcohol use, however, few have been applied to cannabis use and driving under the influence of cannabis (DUIC). This Delphi study sought to create and compare consensus among a panel of experts (potential intervention developers) and a panel of youth (intervention audience) on the characteristics to prioritize in a youth DUIC mobile-based brief intervention. METHODS: A two-round two-panel Delphi study was conducted among 26 professionals with expertise in youth substance use and impaired driving and 20 youth who use cannabis. Participants ranked the importance of 45 evidence-informed intervention characteristics using a 7-point Likert scale. Characteristics that received an interquartile deviation score ≤ 1 (indicating consensus) and a median score of ≥6 (indicating importance) in both panels were considered shared priorities. Differences in panel rankings were quantified using Mann-Whitney U tests. RESULTS: Consensus was achieved for 41 characteristics in the professional panel and 34 in the youth panel, with ratings generally higher among professionals. Overall, 16 shared priorities emerged. These include critical theoretical characteristics (e.g., self-efficacy, motivation, overcoming barriers), practical characteristics (e.g., mobile availability, estimates of intervention length, ability to input behaviours) and core contents (e.g., real-life stories, education on the risks/dangers, appropriate messaging). Youth's perceptions on the dangers of DUIC received the most support for an intervention outcome. CONCLUSIONS: Findings can inform the development of mobile-based brief interventions for youth, an essential step in reducing DUIC among youth and addressing this public health concern.

High Altitude as a Risk Factor for Venous Thromboembolism in Tibial Plateau Fractures.

Background: Tibial plateau fractures are often significant injuries that can require complex surgical interventions with prolonged perioperative immobilization, thereby increasing the risk of developing venous thromboembolic (VTE) events, specifically, deep vein thrombosis (DVT) and pulmonary embolism (PE). Risk stratification is paramount for guiding VTE prophylaxis. Although high altitude has been suggested to create a prothrombotic state, virtually no studies have explored its clinical effects in lower extremity trauma. The purpose of this study was to compare surgical fixation of tibial plateau fractures at high and low altitudes and its effects on post-operative VTE development. Methods: The Truven MarketScan claims database was used to retrospectively identify patients who underwent surgical fixation of isolated and closed tibial plateau fractures using Current Procedural Terminology (CPT) codes over a 10-year period. Extraneous injuries were excluded using the International Classification of Diseases, 10th edition (ICD-10), and CPT codes. Patient demographics, comorbidities, and DVT chemoprophylaxis prescriptions were obtained. Patients were partitioned into high altitude (>4000 feet) or low altitude (<100 feet) cohorts based on the zip codes of their surgery locations. One-to-one matching and univariate analysis were used to assess and control any baseline discrepancies between cohorts; multivariate regression was then performed between cohorts to determine the odds ratios (OR) for developing VTEs post-operatively. Results: There were 7,832 patients included for analysis. There was no statistical difference between high and low altitude cohorts in developing VTEs within 30 days post-operatively. Higher altitudes were associated with increased odds of developing DVT (OR 1.21, p = 0.043) and PE (OR 1.27, p = 0.037) within 90 days post-operatively. Conclusions: Surgical fixation of tibial plateau fractures is associated with an increased risk of developing VTEs at high altitudes within 90 days post-operatively. Understanding such risk factors in specific orthopaedic patient populations is essential for optimizing DVT prophylaxis protocols. Further studies should investigate this relationship and the role of DVT prophylaxis regimens in this population.

Fixation vs Arthroplasty for Femoral Neck Fracture in Patients Aged 40-59 Years: A Propensity-Score-Matched Analysis.

Background: Internal fixation (IF) has historically been favored for the treatment of femoral neck fractures (FNFs) in young, nongeriatric patients. However, recent literature reporting high reoperation rates among those receiving IF, taken in conjunction with favorable survivorship of modern bearing surfaces in total hip arthroplasty (THA), has begun to question this paradigm. Our study sought to compare outcomes between IF and THA for FNFs in patients aged 40-59 years. Methods: Using the Truven MarketScan Database, we performed a retrospective propensity-score-matched cohort study on patients aged 40-59 years who underwent surgical management of an isolated FNF (THA or IF). Patients with pathologic fracture were not included. Analysis was conducted on patients aged 40-49 and 50-59 years separately. A subgroup analysis was performed on those patients with 1 year and 3 years of follow-up. Multivariate analysis, controlling for baseline patient information, was then performed. Results: Seven hundred sevety-eight 40- to 49-year-old patients and 3470 50- to 59-year-old matched patients (IF and THA) were included in this study. A multivariate analysis found that patients aged 40-49 years who underwent IF were at higher odds of both 1-year (odds ratio 2.35, 95% confidence interval 1.22-4.54, P = .011) and 3-year (odds ratio 5.68, 95% confidence interval 2.21-14.60, P < .001) reoperation. Similar results were found in those aged 50-59 years. While complication rates were similar, postoperative anemia and 90-day visits to the emergency room were more common after THA in both age cohorts. Conclusions: While THA is associated with increased postoperative anemia and resource utilization compared with IF, patients aged 40-59 years who undergo IF for FNF are at increased risk of reoperation in the first 3 postoperative years. This information should be used to assist in shared decision-making with patients in this age group.

The effect of first-time 4-wheeled walker use on the gait of younger and older adults.

INTRODUCTION: The 4-wheeled walker is intended to enhance balance and gait for older adults. Yet, some research suggests that walking aids increase falls risk. An understanding of the influence of age with walker use on gait performance is required. OBJECTIVE: To examine the effect of initial 4-wheeled walker use on spatiotemporal gait parameters between younger and older adults. DESIGN: Cross-sectional, repeated-measures. SETTING: Community-dwelling. PARTICIPANTS: Twenty-five younger (age: 26.5 ± 4.1 years) and 24 older (age: 68.5 ± 10.5 years) adults participated. Younger adults were aged 18 to 35 years, whereas older adults were 50 years or older. Included were people not requiring the use of a walking aid, and those able to converse in English. INTERVENTIONS: Not applicable. MAIN OUTCOME MEASURE(S): Gait velocity and stride time variability were recorded using accelerometers. Gait was examined under three conditions: unassisted walking; walking with a 4-wheeled walker; and walking with a 4-wheeled walker while completing a secondary task. Conditions were performed across two walking paths: straight and figure-of-8 Walk Test. Separate mixed-methods analyses of variance (ANOVAs; within-subject: condition/path; between-subject: group) were used for statistical analyses. RESULTS: Velocity was lower when walking using a walker while completing a cognitive task (p < .001), in the figure-of-8 Walk Test (p < .001), and in older adults (p = .001). Stride time variability increased with walking path and condition difficulty (p < .001) for the straight path versus the figure-of-8 Walk Test. CONCLUSIONS: Using a 4-wheeled walker resulted in a slower and more inconsistent gait pattern across both age groups. Walking more complex configurations resulted in the prioritization of gait over the cognitive task while performing the dual-task conditions. No evidence of an age-related difference in the effect of initial walker use on gait was observed. Nonetheless, walkers are cognitively demanding and their introduction should warrant a clinical follow-up.

A rapid electromechanical model to predict reverse remodeling following cardiac resynchronization therapy.

Cardiac resynchronization therapy (CRT) is an effective therapy for patients who suffer from heart failure and ventricular dyssynchrony such as left bundle branch block (LBBB). When it works, it reverses adverse left ventricular (LV) remodeling and the progression of heart failure. However, CRT response rate is currently as low as 50-65%. In theory, CRT outcome could be improved by allowing clinicians to tailor the therapy through patient-specific lead locations, timing, and/or pacing protocol. However, this also presents a dilemma: there are far too many possible strategies to test during the implantation surgery. Computational models could address this dilemma by predicting remodeling outcomes for each patient before the surgery takes place. Therefore, the goal of this study was to develop a rapid computational model to predict reverse LV remodeling following CRT. We adapted our recently developed computational model of LV remodeling to simulate the mechanics of ventricular dyssynchrony and added a rapid electrical model to predict electrical activation timing. The model was calibrated to quantitatively match changes in hemodynamics and global and local LV wall mass from a canine study of LBBB and CRT. The calibrated model was used to investigate the influence of LV lead location and ischemia on CRT remodeling outcome. Our model results suggest that remodeling outcome varies with both lead location and ischemia location, and does not always correlate with short-term improvement in QRS duration. The results and time frame required to customize and run this model suggest promise for this approach in a clinical setting.

Individual variability in animal-specific hemodynamic compensation following myocardial infarction.

Ventricular enlargement and heart failure are common in patients who survive a myocardial infarction (MI). There is striking variability in the degree of post-infarction ventricular remodeling, however, and no one factor or set of factors have been identified that predicts heart failure risk well. Sympathetic activation directly and indirectly modulates hypertrophic stimuli by altering both neurohormonal milieu and ventricular loading. In a recent study, we developed a method to identify the balance of reflex compensatory mechanisms employed by individual animals following MI based on measured hemodynamics. Here, we conducted prospective studies of acute myocardial infarction in rats to test the degree of variability in reflex compensation as well as whether responses to pharmacologic agents targeted at those reflex mechanisms could be anticipated in individual animals. We found that individual animals use very different mixtures of reflex compensation in response to experimental coronary ligation. Some of these mechanisms were related - animals that compensated strongly with venoconstriction tended to exhibit a decrease in the contractility of the surviving myocardium and those that increased contractility tended to exhibit venodilation. Furthermore, some compensatory mechanisms - such as venoconstriction - increased the extent of predicted ventricular enlargement. Unfortunately, initial reflex responses to infarction were a poor predictor of subsequent responses to pharmacologic agents, suggesting that customizing pharmacologic therapy to individuals based on an initial response will be challenging.

The influence of boundary conditions and protein availability on the remodeling of cardiomyocytes.

The heart muscle is capable of growing and remodeling in response to changes in its mechanical and hormonal environment. While this capability is essential to the healthy function of the heart, under extreme conditions it may also lead to heart failure. In this work, we derive a thermodynamically based and microscopically motivated model that highlights the influence of mechanical boundary conditions and hormonal changes on the remodeling process in cardiomyocytes. We begin with a description of the kinematics associated with the remodeling process. Specifically, we derive relations between the macroscopic deformation, the number of sarcomeres, the sarcomere stretch, and the number of myofibrils in the cell. We follow with the derivation of evolution equations that describe the production and the degradation of protein in the cytosol. Next, we postulate a dissipation-based formulation that characterizes the remodeling process. We show that this process stems from a competition between the internal energy, the entropy, the energy supplied to the system by ATP and other sources, and dissipation mechanisms. To illustrate the merit of this framework, we study four initial and boundary conditions: (1) a myocyte undergoing isometric contractions in the presence of either an infinite or a limited supply of proteins and (2) a myocyte that is free to dilate along the radial direction with an infinite and a limited supply of proteins. This work underscores the importance of boundary conditions on the overall remodeling response of cardiomyocytes, suggesting a plausible mechanism that might play a role in distinguishing eccentric vs. concentric hypertrophy.

A Simulation Systems Testing Program Using HFMEA Methodology Can Effectively Identify and Mitigate Latent Safety Threats for a New On-Site Helipad.

BACKGROUND: Fundamental changes in critical systems within hospitals present safety risks. Some threats can be identified prospectively, others are only uncovered when the system goes live. Simulation and Healthcare Failure Mode and Effect Analysis (HFMEA) can be used together to prospectively test a system without endangering patients. The research team combined iterative simulations and HFMEA methodologies to conduct simulation-based clinical systems testing (SbCST) to detect and mitigate latent safety threats (LSTs) prior to opening a hospital helipad. METHODS: This study was conducted in three phases. In Phase I, an interprofessional team created a process map and conducted a tabletop exercise, identifying LSTs that could theoretically occur during patient transfer from the new helipad. Using HFMEA methodology, steps predicted to be affected by the new helipad were probed. Identified LSTs were assigned a hazard score. Mitigation solutions were proposed. Results from Phase I were used to plan Phase II, which used low-fidelity simulation to test communication processes and travel paths. High-fidelity simulation was used in Phase III to test previously identified LSTs. RESULTS: Over three testing phases, 31 LSTs were identified: 15 in Phase I, 7 in Phase II, and 9 in Phase III. LSTs fell under the categories of care coordination, facilities, and equipment, and devices. Eighteen (58.1%) were designated "critical" (hazard score ≥ 8). CONCLUSION: A three-phase SbCST program using HFMEA methodology was an effective tool to identify LSTs. An iterative approach, using results of each phase to inform the structure of the next, facilitated testing of proposed mitigation strategies.

Young drivers' determinants of driving under the influence of cannabis: Findings from the Youth Cannabis and Driving Survey (YouCanDS).

INTRODUCTION: Driving under the influence of cannabis (DUIC) is proven to increase the risk of collisions and is most common among young drivers (ages 16 to 24). However, little is known about the specific determinants of DUIC behavior among youth, which limits the capacity to develop evidence-based prevention and intervention efforts. This study developed and evaluated a youth DUIC questionnaire, which was used to establish the DUIC determinants of young drivers. METHOD: The questionnaire was based on the theoretical framework of general deterrence and general prevention. Data obtained included: demographics, past cannabis use and DUIC experiences, DUIC intention, experiences riding as a passenger with someone DUIC, knowledge and credibility of the law, attitudes towards DUIC, and social controls. The resulting questionnaire was validated for a sample of 426 young drivers in the province of Ontario, Canada. An ordinal regression was conducted to examine the relationships between questionnaire items and DUIC intention. RESULTS: The questionnaire displayed good construct validity and internal consistency across four out of five domains (KMO and Cronbach α values ≥ 0.70). Of the 426 respondents (52.6% female), 356 (83.6%) reported previous cannabis use, with 296 (69.5%) doing so in the past year, and 142 (33.3%) reporting DUIC. Furthermore, 179 (42%) study participants indicated at least a slight chance of DUIC in the next year. The regression analysis identified six variables predictive of DUIC intention: past DUIC incidence, perceived percent of those convicted that receive the penalty, moral awareness, perceived dangerousness, minor accident risk, and vicarious punishment avoidance. CONCLUSIONS: Preventive efforts should emphasize these determinants when designing targeted strategies and interventions. Practical Applications: These efforts should focus on educating the dangers and risk of a vehicle collision, that law enforcement has the capacity to apprehend and appropriately punish individuals DUIC, and that DUIC is wrong and socially unacceptable.

Cardiac Magnetic Resonance Assessment of Response to Cardiac Resynchronization Therapy and Programming Strategies.

OBJECTIVES: The objective was to determine the feasibility and effectiveness of cardiac magnetic resonance (CMR) cine and strain imaging before and after cardiac resynchronization therapy (CRT) for assessment of response and the optimal resynchronization pacing strategy. BACKGROUND: CMR with cardiac implantable electronic devices can safely provide high-quality right ventricular/left ventricular (LV) ejection fraction (RVEF/LVEF) assessments and strain. METHODS: CMR with cine imaging, displacement encoding with stimulated echoes for the circumferential uniformity ratio estimate with singular value decomposition (CURE-SVD) dyssynchrony parameter, and scar assessment was performed before and after CRT. Whereas the pre-CRT scan constituted a single "imaging set" with complete volumetric, strain, and scar imaging, multiple imaging sets with complete strain and volumetric data were obtained during the post-CRT scan for biventricular pacing (BIVP), LV pacing (LVP), and asynchronous atrial pacing modes by reprogramming the device outside the scanner between imaging sets. RESULTS: 100 CMRs with a total of 162 imaging sets were performed in 50 patients (median age 70 years [IQR: 50-86 years]; 48% female). Reduction in LV end-diastolic volumes (P = 0.002) independent of CRT pacing were more prominent than corresponding reductions in right ventricular end-diastolic volumes (P = 0.16). A clear dependence of the optimal CRT pacing mode (BIVP vs LVP) on the PR interval (P = 0.0006) was demonstrated. The LVEF and RVEF improved more with BIVP than LVP with PR intervals ≥240 milliseconds (P = 0.025 and P = 0.002, respectively); the optimal mode (BIVP vs LVP) was variable with PR intervals <240 milliseconds. A lower pre-CRT displacement encoding with stimulated echoes (DENSE) CURE-SVD was associated with greater improvements in the post-CRT CURE-SVD (r = -0.69; P < 0.001), LV end-systolic volume (r = -0.58; P < 0.001), and LVEF (r = -0.52; P < 0.001). CONCLUSIONS: CMR evaluation with assessment of multiple pacing modes during a single scan after CRT is feasible and provides useful information for patient care with respect to response and the optimal pacing strategy.

Automated Spatially Targeted Optical Microproteomics Investigates Inflammatory Lesions In Situ.

Tissue microenvironment properties like blood flow, extracellular matrix, or proximity to immune-infiltrate are important regulators of cell biology. However, methods to study regional protein expression in the native tissue environment are limited. To address this need, we developed a novel approach to visualize, purify, and measure proteins in situ using automated spatially targeted optical microproteomics (AutoSTOMP). Here, we report custom codes to specify regions of heterogeneity in a tissue section and UV-biotinylate proteins within those regions. We have developed liquid chromatography-mass spectrometry (LC-MS)/MS-compatible biochemistry to purify those proteins and label-free quantification methodology to determine protein enrichment in target cell types or structures relative to nontarget regions in the same sample. These tools were applied to (a) identify inflammatory proteins expressed by CD68+ macrophages in rat cardiac infarcts and (b) characterize inflammatory proteins enriched in IgG4+ lesions in human esophageal tissues. These data indicate that AutoSTOMP is a flexible approach to determine regional protein expression in situ on a range of primary tissues and clinical biopsies where current tools and sample availability are limited.