Are we talking about practice? A randomized study comparing simulation-based deliberate practice and mastery learning to self-guided practice.

OBJECTIVES: Simulation-based technical skills training is now ubiquitous in medicine, particularly for high acuity, low occurrence (HALO) procedures. Mastery learning and deliberate practice (ML + DP) are potentially valuable educational methods, however, they are resource intensive. We sought to compare the effect of deliberate practice and mastery learning versus self-guided practice on skill performance of the rare, life-saving procedure, a bougie-assisted cricothyroidotomy (BAC). METHODS: We conducted a multi-center, randomized study at five North American emergency medicine (EM) residency programs. We randomly assigned 176 EM residents to either the ML + DP or self-guided practice groups. Three blinded airway experts independently evaluated BAC skill performance by video review before (pre-test), after (post-test) and 6-12 months (retention) after the training session. The primary outcome was post-test skill performance using a global rating score (GRS). Secondary outcomes included performance time and skill performance at the retention test. RESULTS: Immediately following training, GRS scores were significantly higher as mean performance improved from pre-test, (22, 95% CI = 21-23) to post-test (27, 95% CI = 26-28), (p < 0.001) for all participants. However, there was no difference between the groups on GRS scores (p = 0.2) at the post-test or at the retention test (p = 0.2). At the retention test, participants in the ML + DP group had faster performance times (66 s, 95% CI = 57-74) compared to the self-guided group (77 s, 95% CI = 67-86), (p < 0.01). CONCLUSIONS: There was no significant difference in skill performance between groups. Residents who received deliberate practice and mastery learning demonstrated an improvement in skill performance time.

ABSTRAIT: OBJECTIFS: La formation aux compétences techniques fondée sur la simulation est maintenant omniprésente en médecine, en particulier pour les procédures de grande acuité et de faible occurrence (HALO). L'apprentissage de la maîtrise et la pratique délibérée (ML+DP) sont des méthodes éducatives potentiellement précieuses, mais elles exigent beaucoup de ressources. Nous avons cherché à comparer l'effet de la pratique délibérée et de l'apprentissage de la maîtrise par rapport à la pratique autoguidée sur le rendement des compétences de la rare intervention de sauvetage, une cricothyroïdotomie à la bougie. MéTHODES: Nous avons mené une étude multicentrique randomisée dans le cadre de cinq programmes nord-américains de résidence en médecine d'urgence. Nous avons affecté au hasard 176 résidents en SE aux groupes de ML+DP ou de pratique autoguidée. Trois experts des voies respiratoires aveuglés ont évalué de façon indépendante la performance des compétences en BAC par examen vidéo avant (pré-test), après (post-test) et 6 à 12 mois (rétention) après la séance de formation. Le principal résultat a été le rendement des compétences après le test au moyen d'une cote globale (SRC). Les résultats secondaires comprenaient le temps consacré au rendement et le rendement des compétences au test de rétention. RéSULTATS: Immédiatement après la formation, les résultats des SRC étaient beaucoup plus élevés, car le rendement moyen s'est amélioré entre le prétest (22, IC à 95 % = 21 à 23) et le post-test (27, IC à 95 % = 26 à 28), (p < 0,001) pour tous les participants. Cependant, il n'y avait aucune différence entre les groupes sur les scores GRS (p = 0,2) au post-test ou au test de rétention (p = 0,2). Au test de rétention, les participants du groupe ML+DP avaient des temps de performance plus rapides (66 secondes, IC à 95 % = 57 à 74) que ceux du groupe autoguidé (77 secondes, IC à 95 % = 67 à 86) (p < 0,01). CONCLUSIONS: Il n'y avait pas de différence significative dans le rendement des compétences entre les groupes. Les résidents qui ont bénéficié d'une pratique délibérée et d'un apprentissage de la maîtrise ont démontré une amélioration du temps consacré aux compétences.

Well-tempered metadynamics applied to field-theoretic simulations of diblock copolymer melts.

Well-tempered metadynamics (WTMD) is applied to field-theoretic simulations (FTS) to locate the order-disorder transition (ODT) in incompressible melts of diblock copolymer with an invariant polymerization index of N̄=104. The polymers are modeled as discrete Gaussian chains with N = 90 monomers, and the incompressibility is treated by a partial saddle-point approximation. Our implementation of WTMD proves effective at locating the ODT of the lamellar and cylindrical regions, but it has difficulty with that of the spherical and gyroid regions. In the latter two cases, our choice of order parameter cannot sufficiently distinguish the ordered and disordered states because of the similarity in microstructures. The gyroid phase has the added complication that it competes with a number of other morphologies, and thus, it might be beneficial to extend the WTMD to multiple order parameters. Nevertheless, when the method works, the ODT can be located with impressive accuracy (e.g., ΔχN ∼ 0.01).

Field-Theoretic Simulations for Block Copolymer Melts Using the Partial Saddle-Point Approximation.

Field-theoretic simulations (FTS) provide an efficient technique for investigating fluctuation effects in block copolymer melts with numerous advantages over traditional particle-based simulations. For systems involving two components (i.e., A and B), the field-based Hamiltonian, Hf[W-,W+], depends on a composition field, W-(r), that controls the segregation of the unlike components and a pressure field, W+(r), that enforces incompressibility. This review introduces researchers to a promising variant of FTS, in which W-(r) fluctuates while W+(r) tracks its mean-field value. The method is described in detail for melts of AB diblock copolymer, covering its theoretical foundation through to its numerical implementation. We then illustrate its application for neat AB diblock copolymer melts, as well as ternary blends of AB diblock copolymer with its A- and B-type parent homopolymers. The review concludes by discussing the future outlook. To help researchers adopt the method, open-source code is provided that can be run on either central processing units (CPUs) or graphics processing units (GPUs).

A Novel Application of the Modified Angoff Method to Rate Case Difficulty in Simulation-Based Research.

INTRODUCTION: Simulation use in research is often limited by controlling for scenario difficulty when using repeated measures. Our study assesses the feasibility of the Modified Angoff Method to reach expert consensus regarding difficulty of medical simulations. We compared scores with participant physiologic stress. METHODS: Emergency medicine physicians with expertise in simulation education were asked to review 8 scenarios and estimate the percentage of resident physicians who would perform all critical actions using the modified Angoff method. A standard deviation (SD) of less than 10% of estimated percentage correct signified consensus. Twenty-five residents then performed the 6 scenarios that met consensus and heart rate variability (HRV) was measured. RESULTS: During round 1, experts rated 4/8 scenarios within a 10% SD for postgraduate year 3 (PGY3) and 3/8 for PGY4 residents. In round 2, 6/8 simulation scenarios were within an SD of 10% points for both years. Intraclass correlation coefficient was 0.84 for PGY3 ratings and 0.89 for PGY4 ratings. A mixed effects analysis of variance showed no significant difference in HRV change from rest to simulation between teams or scenarios. Modified Angoff Score was not a predictor of HRV (multiple R2 = 0.0176). CONCLUSIONS: Modified Angoff ratings demonstrated consensus in quantifying the estimated percentage of participants who would complete all critical actions for most scenarios. Although participant HRV did decrease during the scenarios, we were unable to significantly correlate this with ratings. This modified Angoff method is a feasible approach to evaluate simulation difficulty for educational and research purposes and may decrease the time and resources necessary for scenario piloting.

Fluctuation correction for the critical transition of symmetric homopolymer blends.

Monte Carlo simulations are performed on structurally symmetric binary homopolymer blends over a wide range of invariant polymerization indices, N¯. A finite-size scaling analysis reveals that certain critical exponents deviate from the expected 3D-Ising values as N¯ increases. However, the deviations are consistent with previous simulations and can be attributed to the fact that the system crosses over to mean-field behavior when the molecules become too large relative to the size of the simulation box. Nevertheless, the finite-size scaling techniques provide precise predictions for the position of the critical transition. Using a previous calibration of the Flory-Huggins interaction parameter, χ, we confirm that the critical point scales as (χN)c=2+cN¯-1∕2 for large N¯, and more importantly we are able to extract a reliable estimate, c≈1.5, for the universal constant.

Universality between Experiment and Simulation of a Diblock Copolymer Melt.

The equivalent behavior among analogous block copolymer systems involving chemically distinct molecules or mathematically different models has long hinted at an underlying universality, but only recently has it been rigorously demonstrated by matching results from different simulations. The profound implication of universality is that simple coarse-grained models can be calibrated so as to provide quantitatively accurate predictions to experiment. Here, we provide the first compelling demonstration of this by simulating a polyisoprene-polylactide diblock copolymer melt using a previously calibrated lattice model. The simulation successfully predicts the peak in the disordered-state structure function, the position of the order-disorder transition, and the latent heat of the transition in excellent quantitative agreement with experiment. This could mark a new era of precision in the field of block copolymer research.

Universality of block copolymer melts.

Simulations of five different coarse-grained models of symmetric diblock copolymers are compared to demonstrate a universal (i.e., model-independent) dependence of the free energy and order-disorder transition (ODT) on the invariant degree of polymerization N̄. The actual values of χN at the ODT approach predictions of the Fredrickson-Helfand (FH) theory for N̄ ≳ 10(4) but significantly exceed FH predictions at lower values characteristic of most experiments. The FH theory fails for modest N̄ because the competing phases become strongly segregated near the ODT, violating an underlying assumption of weak segregation.

Multistate outbreak of toxic anterior segment syndrome, 2005.

PURPOSE: To present the findings of an outbreak of toxic anterior segment syndrome (TASS). SETTING: Six states, 7 ophthalmology surgical centers, United States. METHODS: Cases were identified through electronic communication networks and via reports to a national TASS referral center. Information on the procedure, details of instrument reprocessing, and products used during cataract surgery were also collected. Medications used during the procedures were tested for endotoxin using a kinetic assay. RESULTS: The search identified 112 case patients (median age 74 years) from 7 centers from July 19, 2005, through November 28, 2005. Common presenting clinical features included blurred vision (60%), anterior segment inflammation (49%), and cell deposition (56%). Of the patients, 100 (89%) had been exposed to a single brand of balanced salt solution manufactured by Cytosol Laboratories and distributed by Advanced Medical Optics as AMO Endosol. Two patients continued to have residual symptoms. There were no reports of significant breaches in sterile technique or instrument reprocessing. Of 14 balanced salt solution lots, 5 (35%) had levels exceeding the endotoxin limit (0.5 EU/mL). Based on these findings, the balanced salt solution product was withdrawn, resulting in a termination of the outbreak. CONCLUSIONS: This is the first known report of an outbreak of TASS caused by intrinsic contamination of a product with endotoxin. Ophthalmologists and epidemiologists should be aware of TASS and its common causes. To facilitate investigations of adverse outcomes such as TASS, those performing cataract surgeries should document the type and lot numbers of products used intraoperatively.