Effect of a High-Sensitivity Troponin I and Associated Diagnostic Protocol on Emergency Department Length of Stay: A Retrospective Cohort Study.

Background: The objective of this study was to assess the introduction of a high-sensitivity troponin I (hs-TnI) assay and its associated accelerated protocol on emergency department (ED) length of stay (LOS) for patients presenting with chest pain, compared to an accelerated diagnostic protocol using conventional troponin (TnI) testing. Methods: We conducted a retrospective cohort study of all adults with a primary presenting complaint of chest pain of cardiac origin and a Canadian Triage and Acuity Scale score of 2 or 3, between November 8, 2019 and November 9, 2021, to a tertiary-care urban Canadian ED. The primary outcome was ED LOS. Secondary outcomes included consultation proportions and major adverse cardiac events within 30 days of the index ED visit. Results: A total of 2640 patients presenting with chest pain were included, with 1333 in the TnI group and 1307 in the hs-TnI group. Median ED LOS decreased significantly, from 392 minutes for the TnI group, and 371 minutes for the hs-TnI group (median difference = 21 minutes; 95% confidence interval: 5.3, 36.7). The numbers of consultations and admissions were not statistically different between study periods. The major adverse cardiac events outcomes did not change following the implementation of the hs-TnI test (13.6% vs 13.1%; P = 0.71). Conclusions: The implementation of an accelerated chest pain protocol using an hs-TnI assay in a tertiary-care Canadian ED was associated with a modest reduction of LOS for all patients, and a substantial reduction of LOS for patients undergoing serial troponin testing. This strategy was safe, with no increase in adverse outcomes.

Contexte: Cette étude visait à évaluer l'introduction du dosage de la troponine I de haute sensibilité (hs-TnI) et le protocole accéléré qui lui est associé sur la durée des séjours aux urgences dans le cas des patients qui consultent pour une douleur thoracique, comparativement à un protocole diagnostique accéléré faisant appel à un test de troponine classique (TnI). Méthodologie: Nous avons mené une étude de cohorte rétrospective portant sur tous les adultes qui se sont présentés aux urgences d'un établissement urbain de soins tertiaires canadien entre le 8 novembre 2019 et le 9 novembre 2021 principalement pour une douleur thoracique d'origine cardiaque et dont le score était de 2 ou 3 à l'Échelle canadienne de triage et de gravité (ETG). Le principal critère d'évaluation était la durée du séjour au service des urgences. Les critères d'évaluation secondaires comprenaient la fréquence des consultations et les événements cardiaques indésirables majeurs dans les 30 jours ayant suivi la visite de référence aux urgences. Résultats: Au total, 2640 patients qui s'étaient présentés aux urgences pour une douleur thoracique ont été inclus, 1333 se trouvant dans le groupe TnI et 1307 dans le groupe hs-TnI. La durée médiane du séjour aux urgences a diminué considérablement, passant de 392 minutes dans le groupe TnI à 371 minutes dans le groupe hs-TnI (différence médiane de 21 minutes; intervalle de confiance [IC] à 95 % : 5,3-36,7). Les consultations et les admissions n'ont pas affiché de différence statistique entre les périodes de l'étude. Les événements cardiaques indésirables majeurs n'ont pas varié après l'introduction du dosage de la hs-TnI (13,6 % vs 13,1 %; p = 0,71). Conclusions: L'adoption d'un protocole accéléré pour la douleur thoracique à l'aide du dosage de la hs-TnI au service des urgences d'un établissement de soins tertiaires canadien a été associée à une légère réduction de la durée du séjour pour l'ensemble des patients et à une réduction substantielle de cette durée pour les patients soumis à des analyses de la troponine en série. De plus, cette stratégie était sûre sans hausse des événements indésirables.

Resident Physician Wellness Curriculum: A Study of Efficacy and Satisfaction.

Background Recent literature highlights the alarming prevalence of burnout, depression, and illness during residency training; a trend that is also linked to suboptimal patient care. Dedicated wellness curricula may be one solution to this concerning issue. Purpose To determine the effect of a multi-faceted wellness curriculum during emergency medicine residency training on wellness scores and to assess resident satisfaction with the program. Methods This study was conducted via a longitudinal survey. In 2009, a faculty-derived resident wellness curriculum (F-RWC) was initiated. This program was then bolstered with a parallel resident-derived curriculum (R-RWC) one year later, in 2010. Emergency medicine residents were surveyed in 2009, 2010, and 2011 to assess wellness at baseline, after one year of the F-RWC, and after one year of combined RWCs, respectively. Surveys included two validated assessment instruments (the Brief Resident Wellness Profile (BRWP) and the SF-8TM Health Survey), a satisfaction Likert scale, and a demographics information sheet. Results The survey response rates were 89% (n=17), 100% (n=17), and 83% (n=24) from 2009, 2010, and 2011, respectively, for a total of 58 participants. From baseline in 2009, there was a significant improvement in resident wellness, with the addition of parallel RWC by 2011, as measured by the BRWP (p=0.024). The faces scale, a subset of the BRWP, showed a trend toward benefit but did not reach statistical significance (p=0.085). There was no evidence of a statistically significant change in SF-8TM scores over time. Participants consistently reported positive satisfaction scores with RWC initiatives. Conclusions Dedicated RWC, with input from both faculty and resident physicians, improved wellness during residency training with a high degree of participant satisfaction. Such programs are needed to support resident physicians during their training.

Perspective: Resident physician wellness: a new hope.

Residency training is a challenging period in a physician's career owing to a multitude of stressors perhaps not previously encountered. In some cases, these stressors may culminate in a state of burnout. In response, much has been written about the issues of personal wellness during residency training. Recently, duty hours reform has been the major focus of addressing resident wellness; however, this intervention has established little benefit and has created unintended negative consequences. Alternatively, an emerging solution may be the implementation of resident wellness programs into residency training. Such programs are defined by a combination of active and passive initiatives targeting the various domains of physical, mental, social, and intellectual wellness. In contrast to duty hours reform, resident wellness programs are generally free from controversy and have been shown to improve resident wellness and enhance empathy.This article highlights the salient causes of burnout as it applies to present-day resident physicians and the patient care they provide. Moreover, in the wake of the controversy surrounding duty hours reform, a novel approach to resident wellness involving structured resident wellness programs is discussed. Specifically included are the fundamental components of a wellness program, the advantages held over duty hours reform, methods to evaluate program efficacy, and the current evidence to support these initiatives. Formal wellness curricula, including an evaluative process, should be an integral component of physician training. These programs represent a new hope in the solution to the long-debated issue of burnout and wellness during residency training.

CD44 interacts directly with Lck in a zinc-dependent manner.

CD44 is a widely expressed cell adhesion molecule with functional similarities to the selectin and integrin adhesion molecules. CD44 has a lectin domain that binds hyaluronan, a component of the extracellular matrix. Interactions between CD44 and hyaluronan promote lymphocyte rolling under flow and cell-cell and cell-matrix adhesion. Attachment of lymphocytes to immobilized CD44 antibodies induces cell adhesion and spreading, which is dependent on Src family kinase activity. Both Lck and Fyn associate with CD44 in T cells. CD4 and CD8 associate with Lck via a zinc-dependent interaction that is inhibited by the divalent metal cation chelator, 1,10-phenanthroline. Here we show that both CD4 and CD44-mediated T cell spreading is abolished in the presence of 1,10-phenanthroline and their association with Lck is significantly reduced. In contrast, the co-immunoprecipitation of Fyn by CD44 was unaffected. The cytoplasmic domain of CD44 was required for divalent cation-dependent association of Lck, but not for its association with Fyn. Mutational analysis of CD44 revealed that cysteine residues were not essential for the interaction nor were the carboxy-terminal 41 amino acids. Progressive deletion of the remaining 31 amino acids of the CD44 cytoplasmic domain revealed the importance of this membrane proximal region for its association with Lck. Using purified recombinant proteins, we demonstrated a direct, zinc-inducible interaction between the cytoplasmic domain of CD44 and Lck but not Fyn. The zinc-inducible interaction required the first 13 amino acids of the cytoplasmic domain of CD44 and the non-catalytic regions of Lck. Taken together, we conclude that CD44 directly associates with Lck in a zinc-inducible manner and this is important for the transmission of CD44-mediated signaling events leading to T cell spreading.

A systematic approach to the treatment of HIV and hepatitis C virus infection in the inner city: a Canadian perspective.

The treatment of injection drug users (IDUs) coinfected with human immunodeficiency virus (HIV) and hepatitis C virus (HCV) presents multiple challenges, many of which could be addressed by the development of directly observed therapy programs. This is made all the more feasible by the validation of once-daily treatment regimens for HIV. We have demonstrated that virological suppression can be achieved and maintained in as many as 80% of active IDUs who have received highly active antiretroviral therapy for 48 months. This approach has now been validated in first- and second-line therapy, as well as for the treatment of bacterial infections in this population, achieving therapeutic results similar to those reported in the general population. The model is now being applied to the treatment of HCV infection, focusing on patients with infection due to HCV genotype 2 or 3, in whom the likelihood of response may exceed 80%. Our ultimate goal is to ensure that, even in treating IDUs in the inner city, no patient is left behind.

Subdomain X of the kinase domain of Lck binds CD45 and facilitates dephosphorylation.

CD45 is a transmembrane, two-domain protein-tyrosine phosphatase expressed exclusively in nucleated hematopoietic cells. The Src family kinase, Lck, is a major CD45 substrate in T cells and CD45 dephosphorylation of Lck is important for both T cell development and activation. However, how the substrate specificity of phosphatases such as CD45 is achieved is not well understood. Analysis of the interaction between the cytoplasmic domain of CD45 and its substrate, Lck, revealed that the active, membrane-proximal phosphatase domain of CD45 (CD45-D1) bound to the phosphorylated Lck kinase domain, the SH2 domain, and the unique N-terminal region of Lck. The second, inactive phosphatase domain (CD45-D2) bound only to the kinase domain of Lck. CD45-D2 was unable to bind phosphotyrosine, and its interaction with the kinase domain of Lck was independent of tyrosine phosphorylation. The binding of CD45-D2 was localized to subdomain X (SD10) of Lck. CD45-D2 bound similarly to Src family kinases but bound Csk to a lesser extent and did not bind significantly to the less related kinase, Erk1. CD45 dephosphorylated Lck and Src at similar rates but dephosphorylated Csk and Erk1 at lower rates. Replacement of Erk1 SD10 with that of Lck resulted in the binding of CD45-D2 and the conversion of Erk1 to a more efficient CD45 substrate. This demonstrates a role for CD45-D2 in binding substrate and identifies the SD10 region in Lck as a novel site involved in substrate recognition.

The noncatalytic domains of Lck regulate its dephosphorylation by CD45.

The Src-family tyrosine kinase, Lck, contains two key regulatory phosphotyrosine residues, tyrosine 394 (Tyr-394) and tyrosine 505 (Tyr-505), both of which can be dephosphorylated by CD45. Here, the interaction of CD45 with its substrate, Lck, was determined to be complex, involving multiple interactions with both the catalytic and noncatalytic regions of Lck. CD45 preferentially dephosphorylated Tyr-394 over Tyr-505 in Lck. This was not due to sequence specificity surrounding the phosphotyrosine, but was due to the noncatalytic domains of Lck. The interactions with the noncatalytic domains of Lck and CD45 enhanced the dephosphorylation of Tyr-394 whereas intramolecular interactions within Lck reduced, but did not abolish, the dephosphorylation of Tyr-505. This demonstrates that the noncatalytic domains of Lck regulate the dephosphorylation of both Tyr-394 and Tyr-505 by CD45.