Sex-Dependent Differences in the Ischemia/Reperfusion-Induced Expression of AMPA Receptors.

Following ischemia/reperfusion, AMPA receptors (AMPARs) mediate pathologic delayed neuronal death through sustained expression of calcium-permeable AMPARs, leading to excitotoxicity. Preventing the surface removal of GluA2-containing AMPARs may yield new therapeutic targets for the treatment of ischemia/reperfusion. This study utilized acute organotypic hippocampal slices from aged male and female Sprague Dawley rats and subjected them to oxygen-glucose deprivation/reperfusion (OGD/R) to examine the mechanisms underlying the internalization and degradation of GluA2-containing AMPARs. We determined the effect of OGD/R on AMPAR subunits at the protein and mRNA transcript levels utilizing Western blot and RT-qPCR, respectively. Hippocampal slices from male and female rats responded to OGD/R in a paradoxical manner with respect to AMPARs. GluA1 and GluA2 AMPAR subunits were degraded following OGD/R in male rats but were increased in female rats. There was a rapid decrease in GRIA1 (GluA1) and GRIA2 (GluA2) mRNA levels in the male hippocampus following ischemic insult, but this was not observed in females. These data indicate a sex-dependent difference in how AMPARs in the hippocampus respond to ischemic insult, and may help explain, in part, why premenopausal women have a lower incidence/severity of ischemic stroke compared with men of the same age.

An examination of the effects of eye-tracking on behavior in psychology experiments.

Eye-tracking is emerging as a tool for researchers to better understand cognition and behavior. However, it is possible that experiment participants adjust their behavior when they know their eyes are being tracked. This potential change would be considered a type of Hawthorne effect, in which participants alter their behavior in response to being watched and could potentially compromise the outcomes and conclusions of experimental studies that use eye tracking. We examined whether eye-tracking produced Hawthorne effects in six commonly used psychological scales and five behavioral tasks. The dependent measures were selected because they are widely used and cited and because they involved measures of sensitive topics, including gambling behavior, racial bias, undesirable personality characteristics, or because they require working memory or executive attention resources, which might be affected by Hawthorne effects. The only task where Hawthorne effects manifested was the mixed gambles task, in which participants accepted or rejected gambles involving a 50/50 chance of gaining or losing different monetary amounts. Participants in the eye-tracking condition accepted fewer gambles that were low in expected value, and they also took longer to respond for these low-value gambles. These results suggest that eye-tracking is not likely to produce Hawthorne effects in most common psychology laboratory tasks, except for those involving risky decisions where the probability of the outcomes from each choice are known.

Correlation of Colorectal Surgical Skill With Patient Outcomes: A Cautionary Tale.

BACKGROUND: Previous work has demonstrated a correlation between video ratings of surgical skill and clinical outcomes. Some have proposed the use of video review for technical skill assessment, credentialing, and quality improvement. OBJECTIVE: Before its adoption as a quality measure for colorectal surgeons, we must first determine whether video-based skill assessments can predict patient outcomes among specialty surgeons. DESIGN: Twenty-one surgeons submitted one representative video of a minimally invasive colectomy. Each video was edited to highlight key steps and then rated by 10 peer surgeons using a validated American Society of Colon and Rectal Surgeons assessment tool. Linking surgeons' ratings to a validated surgical outcomes registry, we assessed the relationship between skill and risk-adjusted complication rates. SETTINGS: The study was conducted with the Michigan Surgical Quality Collaborative, a statewide collaborative including 70 community, academic, and tertiary hospitals. PATIENTS: Patients included those who underwent minimally invasive colorectal resection performed by the participating surgeons. MAIN OUTCOME MEASURES: Main outcome measures included 30-day risk-adjusted postoperative complications. RESULTS: The average technical skill rating for each surgeon ranged from 2.6 to 4.6. Risk-adjusted complication rate per surgeon ranged from 9.9% to 33.1%. Patients of surgeons in the bottom quartile of overall skill ratings were older and more likely to have hypertension or to smoke; patients of surgeons in the top quartile were more likely to be immunosuppressed or have an ASA score of 3 or higher. After patient- and surgery-specific risk adjustment, there was no statistically significant difference in complication rates between the bottom and top quartile surgeons (17.5% vs 16.8%, respectively, p = 0.41). LIMITATIONS: Limitations included retrospective cohort design with short-term follow-up of sampled cases. Videos were edited to highlight key steps, and reviewers did not undergo training to establish norms. CONCLUSIONS: Our study demonstrates that video-based peer rating of minimally invasive colectomy was not correlated with postoperative complications among specialty surgeons. As such, the adoption of video review for use in credentialing should be approached with caution. See Video Abstract at http://links.lww.com/DCR/B802.CORRELACIÓN ENTRE LA HABILIDAD QUIRÚRGICA COLORRECTAL Y LOS RESULTADOS OBTENIDOS EN EL PACIENTE: RELATO PRECAUTORIOANTECEDENTES:Trabajos anteriores han demostrado una correlación entre la video-calificación de la habilidad quirúrgica y los resultados clínicos. Algunos autores han propuesto el uso de la revisión de videos para la evaluación de la habilidad técnica, la acreditación y la mejoría en la calidad quirúrgica.OBJETIVO:Antes de su adopción como medida de calidad entre los cirujanos colorrectales, primero debemos determinar si las evaluaciones de habilidades basadas en video pueden predecir los resultados clínicos de los pacientes entre cirujanos especializados.DISEÑO:Veintiún cirujanos enviaron un video representativo de una colectomía mínimamente invasiva. Cada video fue editado para resaltar los pasos clave y luego fué calificado por 10 cirujanos revisores utilizando una herramienta de evaluación validada por la ASCRS. Al vincular las calificaciones de los cirujanos al registro de resultados quirúrgicos aprobado, evaluamos la relación entre la habilidad y las tasas de complicaciones ajustadas al riesgo.AJUSTE:Colaboración en todo el estado incluyendo 70 hospitales comunitarios, académicos y terciarios, el Michigan Surgical Quality Collaborative.PACIENTES:Todos aquellos sometidos a resección colorrectal mínimamente invasiva realizada por los cirujanos participantes.MEDIDA DE RESULTADO PRINCIPAL:Complicaciones posoperatorias ajustadas al riesgo a los 30 días.RESULTADOS:La calificación de la habilidad técnica promedio de cada cirujano osciló entre 2.6 y 4.6. La tasa de complicaciones ajustada al riesgo por cirujano osciló entre el 9,9% y el 33,1%. Los pacientes operados por los cirujanos del cuartil inferior de las calificaciones generales de habilidades eran fumadores y añosos, y tambiés más propensos a la hipertensión arterial. Los pacientes operados por los cirujanos del cuartil superior tenían más probabilidades de ser inmunosuprimidos o tener una puntuación ASA> = 3. Después del ajuste de riesgo específico de la cirugía y el paciente, no hubo diferencias estadísticamente significativas en las tasas de complicaciones entre los cirujanos del cuartil inferior y superior (17,5% frente a 16,8%, respectivamente, p = 0,41).LIMITACIONES:Diseño de cohortes retrospectivo con seguimiento a corto plazo de los casos muestreados. Los videos se editaron para resaltar los pasos clave y los revisores no recibieron capacitación para establecer normas.CONCLUSIONES:Nuestro estudio demuestra que la evaluación realizada por los revisores basada en el video de la colectomía mínimamente invasiva no se correlacionó con las complicaciones post-operatorias entre los cirujanos especialistas. Por tanto, la adopción de la revisión del video quirúrgico para su uso en la acreditación profesional, debe abordarse con mucha precaución. Consulte Video Resumen en http://links.lww.com/DCR/B802. (Traducción-Dr. Xavier Delgadillo).

Oxidative Stress Underlies the Ischemia/Reperfusion-Induced Internalization and Degradation of AMPA Receptors.

Stroke is the fifth leading cause of death annually in the United States. Ischemic stroke occurs when a blood vessel supplying the brain is occluded. The hippocampus is particularly susceptible to AMPA receptor-mediated delayed neuronal death as a result of ischemic/reperfusion injury. AMPA receptors composed of a GluA2 subunit are impermeable to calcium due to a post-transcriptional modification in the channel pore of the GluA2 subunit. GluA2 undergoes internalization and is subsequently degraded following ischemia/reperfusion. The subsequent increase in the expression of GluA2-lacking, Ca2+-permeable AMPARs results in excitotoxicity and eventually delayed neuronal death. Following ischemia/reperfusion, there is increased production of superoxide radicals. This study describes how the internalization and degradation of GluA1 and GluA2 AMPAR subunits following ischemia/reperfusion is mediated through an oxidative stress signaling cascade. U251-MG cells were transiently transfected with fluorescently tagged GluA1 and GluA2, and different Rab proteins to observe AMPAR endocytic trafficking following oxygen glucose-deprivation/reperfusion (OGD/R), an in vitro model for ischemia/reperfusion. Pretreatment with Mn(III)tetrakis(1-methyl-4-pyridyl)porphyrin (MnTMPyP), a superoxide dismutase mimetic, ameliorated the OGD/R-induced, but not agonist-induced, internalization and degradation of GluA1 and GluA2 AMPAR subunits. Specifically, MnTMPyP prevented the increased colocalization of GluA1 and GluA2 with Rab5, an early endosomal marker, and with Rab7, a late endosomal marker, but did not affect the colocalization of GluA1 with Rab11, a marker for recycling endosomes. These data indicate that oxidative stress may play a vital role in AMPAR-mediated cell death following ischemic/reperfusion injury.

Achieving the High-Value Colectomy: Preventing Complications or Improving Efficiency.

BACKGROUND: There is increased focus on the value of surgical care. Postoperative complications decrease value, but it is unknown whether high-value hospitals spend less than low-value hospitals in cases without complications. Previous studies have not evaluated both expenditures and validated outcomes in the same patients, limiting the understanding of interactions between clinical performance, efficient utilization of services, and costliness of surgical episodes. OBJECTIVE: This study aimed to identify payment differences between low- and high-value hospitals in colectomy cases without adverse outcomes using a linked data set of multipayer claims and validated clinical outcomes. DESIGN: This is a retrospective observational cohort study. We assigned each hospital a value score (ratio of cases without adverse outcome to mean episode payment). We stratified hospitals into tertiles by value and used analysis of variance tests to compare payments between low- and high-value hospitals, first for all cases, and then cases without adverse outcome. SETTING: January 2012 to December 2016, this investigation used clinical registry data from 56 hospitals participating in the Michigan Surgical Quality Collaborative, linked with 30-day episode payments from the Michigan Value Collaborative. PATIENTS: A total of 2947 patients undergoing elective colectomy were selected. MAIN OUTCOME MEASURES: The primary outcome measured was risk-adjusted, price-standardized 30-day episode payments. RESULTS: The mean adjusted complication rate was 31% (±10.7%) at low-value hospitals and 14% (±4.6%) at high-value hospitals (p < 0.001). Low-value hospitals were paid $3807 (17%) more than high-value hospitals ($22,271 vs $18,464, p < 0.001). Among cases without adverse outcome, payments were still $2257 (11%) higher in low-value hospitals ($19,424 vs $17,167, p = 0.04). LIMITATIONS: This study focused on outcomes and did not consider processes of care as drivers of value. CONCLUSIONS: In elective colectomy, high-value hospitals achieve lower episode payments than low-value hospitals for cases without adverse outcome, indicating mechanisms for increasing value beyond reducing complications. Worthwhile targets to optimize value in elective colectomy may include enhanced recovery protocols or other interventions that increase efficiency in all phases of care. See Video Abstract at http://links.lww.com/DCR/B56. LOGRANDO LA COLECTOMÍA DE ALTO VALOR: PREVINIENDO COMPLICACIONES O MEJORANDO LA EFICIENCIA: Hay un mayor enfoque en el valor de la atención quirúrgica. Las complicaciones postoperatorias disminuyen el valor, pero se desconoce si en los casos sin complicaciones, los hospitales de alto valor gastan menos que los hospitales de bajo valor. Estudios anteriores no han evaluado ambos gastos y validado resultados en los mismos pacientes, limitando la comprensión de las interacciones entre el rendimiento clínico, utilización eficiente de los servicios y costos de los episodios quirúrgicos.Identificar las diferencias de pago entre los hospitales de alto y bajo valor, en casos de colectomía sin resultados adversos, utilizando un conjunto de datos vinculados de reclamos de pago múltiple y resultados clínicos validados.Estudio de cohorte observacional retrospectivo. Asignamos a cada hospital una puntuación de valor (proporción de casos sin resultado adverso al pago medio del episodio). Estratificamos los hospitales por valor en terciles y utilizamos el análisis de pruebas de varianza para comparar los pagos entre hospitales de bajo y alto valor, primero para todos los casos y luego casos sin resultados adversos.De enero del 2012 a diciembre del 2016, utilizando datos de registro clínico de 56 hospitales que participan en el Michigan Surgical Quality Collaborative, vinculado con pagos de episodios de 30 días, del Michigan Value Collaborative.Un total de 2947 pacientes con colectomía electiva.Pagos por episodio de 30 días, ajustados al riesgo y estandarizados por precio.La tasa media de complicación ajustada fue de 31% (±10.7%) en hospitales de bajo valor y 14% (±4.6%) en hospitales de alto valor (p < 0.001). A los hospitales de bajo valor se les pagó $3807 (17%) más que a los hospitales de alto valor ($22,271 frente a $18,464, p < 0.001). Entre los casos sin resultados adversos, los pagos fueron de $2257 (11%) más altos en hospitales de bajo valor ($19,424 vs $17,167, p = 0.04).Este estudio se centró en los resultados y no se consideraron a los procesos de atención, como impulsores de valor.En la colectomía electiva, los hospitales de alto valor logran pagos de episodios más bajos, que en los hospitales de bajo valor con casos sin resultados adversos, indicando mecanismos para aumentar el valor, más allá que la reducción de complicaciones. Objetivos valiosos para optimizar el valor de la colectomía electiva, pueden incluir mejoras en los protocolos de recuperación, así como otras intervenciones que aumenten la eficiencia en todas las fases de la atención. Vea el resumen del video en http://links.lww.com/DCR/B56.

Uptake of Total Mesorectal Excision and Total Mesorectal Excision Grading for Rectal Cancer: A Statewide Study.

BACKGROUND: Total mesorectal excision is associated with decreased local recurrence and improved disease-free survival following rectal cancer resection. The extent to which total mesorectal excision has been adopted in the United States is unknown. OBJECTIVE: We sought to assess trends in total mesorectal excision performance and grading in Michigan hospitals. DESIGN: This is a retrospective cohort study from the Michigan Surgical Quality Collaborative. Trends in total mesorectal excision performance and grade assignment were analyzed by using χ tests and linear regression. SETTINGS: Participating hospitals (initially 14 hospitals, now 38) abstracted medical records data for rectal cancer cases from 2007 to 2016. PATIENTS: Patients who underwent rectal cancer resection were included. MAIN OUTCOME MEASURE: The main outcome measures were surgeon-documented total mesorectal excision performance and pathologist-reported total mesorectal excision grade. RESULTS: Of 510 rectal cancer cases, 367 (72.0%) had surgeon-reported total mesorectal excision performance and 78 (15.3%) had pathologist-reported total mesorectal excision grade. Between-hospital variability in total mesorectal excision performance ranged from 0% to 97% and total mesorectal excision grading ranged from 0% to 90%. Total mesorectal excision grading was associated with a higher likelihood of also having adequate lymph node assessment (88.5% versus 71.9%, p = 0.002). There has been a statistically significant trend toward an increase in total mesorectal excision grading in the original 14 hospitals (p = 0.001), but not in the complete cohort of all hospitals (p = 0.057). LIMITATIONS: This is a retrospective cohort design with sampled rectal cancer cases. In addition, there is insufficient granularity to capture all factors associated with total mesorectal excision performance or grade assignment. CONCLUSIONS: The rates of total mesorectal excision performance and grade assignment are widely variable throughout the state of Michigan. Overall, grade assignment remains very low. This suggests an opportunity for quality improvement projects to increase total mesorectal excision performance and grading, involving both the surgeons and pathologists for effective implementation. See Video Abstract at http://links.lww.com/DCR/B53. IMPLEMENTACIÓN DE LA ESCISIÓN MESORRECTAL TOTAL Y LA CLASIFICACIÓN POR ESCISIÓN MESORRECTAL TOTAL PARA EL CÁNCER RECTAL: UN ESTUDIO A NIVEL ESTATAL.: La escisión mesorrectal total se asocia con una menor recurrencia local y una mejor supervivencia libre de enfermedad después de la resección del cáncer rectal. Se desconoce hasta que punto se ha adoptado la escisión mesorrectal total en los Estados Unidos.Se intento evaluar las tendencias en el rendimiento y la clasificación de la escisión mesorrectal total en los hospitales de Michigan.Este es un estudio de cohorte retrospectivo de la "Michigan Surgical Quality Collaborative". Las tendencias en el rendimiento de la escisión mesorrectal total y la asignación de grado se analizaron mediante pruebas de chi-cuadrada y regresión lineal.Los hospitales participantes (inicialmente 14 hospitales, ahora 38) extrajeron datos de registros médicos de los casos de cáncer rectal desde 2007 hasta 2016.Pacientes que se sometieron a resección de cáncer rectal.Las principales medidas de resultado fueron el rendimiento de la escisión mesorrectal total documentado por el cirujano y el grado de escisión mesorrectal total informada por el patólogo.De 510 casos de cáncer rectal, 367 (72.0%) tenían un rendimiento de escisión mesorrectal total reportado por el cirujano y 78 (15.3%) tenían un grado de escisión mesorrectal total reportado por el patólogo. La variabilidad entre hospitales en el rendimiento de la escisión mesorrectal total varió del 0 al 97% y la clasificación de la escisión mesorrectal total varió del 0 al 90%. La clasificación de la escisión mesorrectal total se asoció con una mayor probabilidad de tener también una evaluación adecuada de los ganglios linfáticos (88.5% versus 71.9%, p = 0.002). Ha habido una tendencia estadísticamente significativa hacia un aumento en la clasificación de la escisión mesorrectal total en los 14 hospitales originales (p = 0.001), pero no en la cohorte completa de todos los hospitales (p = 0.057).Diseño de cohorte retrospectivo con casos de cáncer rectal muestreados. Además, no hay suficiente granularidad para capturar todos los factores asociados con el rendimiento de la escisión mesorrectal total o la asignación de grados.Las tasas de rendimiento de escisión mesorrectal total y asignación de grado son muy variables en todo el estado de Michigan. En general, la asignación de calificaciones sigue siendo muy baja. Esto sugiere una oportunidad para que los proyectos de mejora de la calidad aumenten el rendimiento y la clasificación de la escisión mesorrectal total, involucrando tanto a los cirujanos como a los patólogos para una implementación efectiva. Vea el resumen del video en http://links.lww.com/DCR/B53.

Gas Permeation Properties, Physical Aging, and Its Mitigation in High Free Volume Glassy Polymers.

Hundreds of polymers have been evaluated as membrane materials for gas separations, but fewer than 10 have made it into current commercial applications, mainly due to the effects of physical aging and plasticization. Efforts to overcome these two problems are a significant focus in gas separation membrane research, in conjunction with improving membrane separation performance to surpass the Robeson upper bounds of selectivity versus permeability for commercially important gas pairs. While there has been extensive research, ranging from manipulating the chemistry of existing polymers (e.g., thermally rearranged or cross-linked polyimides) to synthesizing new polymers such as polymers of intrinsic microporosity (PIMs), there have been three major oversights that this review addresses: (1) the need to compare the approaches to achieving the best performance in order to identify their effectiveness in improving gas transport properties and in mitigating aging, (2) a common standardized aging protocol that allows rapid determination of the success (or not) of these approaches, and (3) standard techniques that can be used to characterize aging and plasticization across all studies to enable them to be robustly and equally compared. In this review, we also provide our perspectives on a few key aspects of research related to high free volume polymer membranes: (1) the importance of Robeson plots for membrane aging studies, (2) eliminating thermal history, (3) measurement and reporting of gas permeability and aging rate, (4) aging and storing conditions, and (5) promising approaches to mitigate aging.

Structural characterization of nonactive site, TrkA-selective kinase inhibitors.

Current therapies for chronic pain can have insufficient efficacy and lead to side effects, necessitating research of novel targets against pain. Although originally identified as an oncogene, Tropomyosin-related kinase A (TrkA) is linked to pain and elevated levels of NGF (the ligand for TrkA) are associated with chronic pain. Antibodies that block TrkA interaction with its ligand, NGF, are in clinical trials for pain relief. Here, we describe the identification of TrkA-specific inhibitors and the structural basis for their selectivity over other Trk family kinases. The X-ray structures reveal a binding site outside the kinase active site that uses residues from the kinase domain and the juxtamembrane region. Three modes of binding with the juxtamembrane region are characterized through a series of ligand-bound complexes. The structures indicate a critical pharmacophore on the compounds that leads to the distinct binding modes. The mode of interaction can allow TrkA selectivity over TrkB and TrkC or promiscuous, pan-Trk inhibition. This finding highlights the difficulty in characterizing the structure-activity relationship of a chemical series in the absence of structural information because of substantial differences in the interacting residues. These structures illustrate the flexibility of binding to sequences outside of-but adjacent to-the kinase domain of TrkA. This knowledge allows development of compounds with specificity for TrkA or the family of Trk proteins.

Association Between Hospital Staffing Models and Failure to Rescue.

OBJECTIVE: To identify hospital staffing models associated with failure to rescue (FTR) rates at low- and high-performing hospitals. BACKGROUND: FTR is an important quality measure in surgical safety and is a metric that hospitals are seeking to improve. Specific unit-level determinants of FTR, however, remain unknown. METHODS: Retrospective, observational study using data from the Michigan Quality Surgical Collaborative, which is a prospectively collected and clinically audited database in the state of Michigan. We identified 44,567 patients undergoing major general or vascular surgery from 2008 to 2012. Our main outcome measures were mortality, complications, and FTR rates. RESULTS: Hospital rates of FTR across low, middle, and high tertiles were 8.9%, 16.5%, and 19.9%, respectively (P < 0.001). Low FTR hospitals tended to have a closed intensive care unit staffing model (56% vs 20%, P < 0.001) and a higher proportion of board-certified intensivists (88% vs 60%, P < 0.001) when compared to high FTR hospitals. There was also significantly more staffing of low FTR hospitals by hospitalists (85% vs 20%, P < 0.001) and residents (62% vs 40%, P < 0.01). Low FTR hospitals were noted to have more overnight coverage (75% vs 45%, P < 0.001) as well as a dedicated rapid response team (90% vs 60%, P < 0.001). CONCLUSIONS: Low FTR hospitals had significantly more staffing resources than high FTR hospitals. Although hiring additional staff may be beneficial, there remain significant financial limitations for many hospitals to implement robust staffing models. Thus, our ongoing work seeks to improve rescue and implement effective staffing strategies within these constraints.

Targeting Value-Driven Quality Improvement for Laparoscopic Cholecystectomy in Michigan.

OBJECTIVE: The purpose of this study was to evaluate complete episode expenditures for laparoscopic cholecystectomy, a common and lower-risk operation, to characterize novel targets for value-based quality improvement. SUMMARY BACKGROUND DATA: Despite enthusiasm for improving the overall value of surgical care, most efforts have focused on high-risk inpatient surgery. METHODS: We identified 19,213 patients undergoing elective laparoscopic cholecystectomy from 2012 to 2015 using data from Medicare and a large private payer. We calculated price-standardized payments for the entire surgical episode of care and stratified patients by surgeon. We used linear regression to risk- and reliability-adjusted expenditures for patient characteristics, diagnoses, and the use of additional procedures. RESULTS: Fully adjusted total episode costs varied 2.4-fold across surgeons ($7922-$17,500). After grouping surgeons by adjusted total episode payments, each component of the total episode was more expensive for patients treated by the most expensive versus the least expensive quartile of surgeons. For example, payments for physician services were higher for the most expensive surgeons [$1932, 95% confidence interval (CI) $1844-$2021] compared to least expensive surgeons ($1592, 95% CI $1450-$1701, P < 0.01). Overall differences were driven by higher rates of complications (10% vs. 5%) and readmissions (14% vs. 8%), and lower rates of ambulatory procedures (77% vs. 56%) for surgeons with the highest versus lowest expenditures. Projections showed that a 10% increase ambulatory operations would yield $3.6 million in annual savings for beneficiaries. CONCLUSIONS: Episode payments for laparoscopic cholecystectomy vary widely across surgeons. Although improvements in several domains would reduce expenditures, efforts to expand ambulatory surgical practices may result in the largest savings to beneficiaries in Michigan.

Substance use is associated with reduced devaluation sensitivity.

Substance use has been linked to impairments in reward processing and decision-making, yet empirical research on the relationship between substance use and devaluation of reward in humans is limited. We report findings from two studies that tested whether individual differences in substance use behavior predicted reward learning strategies and devaluation sensitivity in a nonclinical sample. Participants in Experiment 1 (N = 66) and Experiment 2 (N = 91) completed subscales of the Externalizing Spectrum Inventory and then performed a two-stage reinforcement learning task that included a devaluation procedure. Spontaneous eye blink rate was used as an indirect proxy for dopamine functioning. In Experiment 1, correlational analysis revealed a negative relationship between substance use and devaluation sensitivity. In Experiment 2, regression modeling revealed that while spontaneous eyeblink rate moderated the relationship between substance use and reward learning strategies, substance use alone was related to devaluation sensitivity. These results suggest that once reward-action associations are established during reinforcement learning, substance use predicted reduced sensitivity to devaluation independently of variation in eyeblink rate. Thus, substance use is not only related to increased habit formation but also to difficulty disengaging from learned habits. Implications for the role of the dopaminergic system in habitual responding in individuals with substance use problems are discussed.

Acute stress improves long-term reward maximization in decision-making under uncertainty.

Acute stress influences reward-seeking tendencies and risky decision-making. However, it is unclear how acute stress influences decision-making in situations in which individuals must learn to either maximize long-term or immediate rewards from experience. Consequently, this study sought to investigate whether acute stress enhances salience of small, immediate or large, delayed rewards on decision-making under uncertainty. The Socially Evaluated Cold Pressor Task (SECPT) was used to induce acute stress. Participants in Experiment 1 (N = 50) were exposed to either the SECPT or a warm-water control condition and then completed a decision-making task in which participants needed to learn to forego immediate rewards in favor of larger delayed rewards. The results demonstrated that acute stress enhanced decisions that maximized long-term, large rewards over immediate, small rewards. Experiment 2 (N = 50) included an assessment of salivary cortisol. Results replicated the behavioral findings in Experiment 1 and demonstrated that the acute stress manipulation increased salivary cortisol, thus providing a potential physiological mechanism for these results. This work suggests that moderate acute stress can improve decision-making under uncertainty that depends on learning to maximize long-term rewards from experience.

Mechanisms of age and race differences in receiving minimally invasive inguinal hernia repair.

BACKGROUND: Black patients and older adults are less likely to receive minimally invasive hernia repair. These differences by race and age may be influenced by surgeon-specific utilization rate of minimally invasive repair. In this study, we explored the association between race, age, and surgeon utilization of minimally invasive surgery (MIS) with the likelihood of receiving MIS inguinal hernia repair. METHODS: A retrospective cohort study was performed in patients undergoing elective primary inguinal hernia repair from 2012 to 2016, using data from the Michigan Surgical Quality Collaborative, a 72-hospital clinical registry. Surgeons were stratified by proportion of MIS performed. Using hierarchical logistic regression models, we investigated the association between receiving MIS repair and race, age, and surgeon MIS utilization rate. RESULTS: Out of 4667 patients, 1253 (27%) received MIS repair. Out of 190 surgeons, 81 (43%) performed only open repair. Controlling for surgeon MIS utilization, race was not associated with MIS receipt (OR 0.93, p = 0.775), but older patients were less likely to receive MIS repair (OR 0.41, p < 0.001). CONCLUSIONS: Race differences were explained by surgeon MIS utilization, implicating access to MIS-performing surgeon as a mediator. Conversely, age disparity was independent of MIS utilization, even after adjusting for comorbidities, indicating some degree of provider bias against performing MIS repair in older patients. Interventions to address disparities should include systematic efforts to improve access, as well as provider and patient education for older adults.

Surgeon utilization of minimally invasive techniques for inguinal hernia repair: a population-based study.

BACKGROUND: MIS utilization for inguinal hernia repair is low compared to in other procedures. The impact of low adoption in surgeons is unclear, but may affect regional access to minimally invasive surgery (MIS). We explored the impact of surgeon MIS utilization in inguinal hernia repair across a statewide population. METHODS: We analyzed 6723 patients undergoing elective inguinal hernia repair from 2012 to 2016 in the Michigan Surgical Quality Collaborative. The primary outcome was surgeon MIS utilization. The geographic distribution of high MIS-utilizing surgeons was compared across Hospital Referral Regions using Pearson's Chi-squared test. Hierarchical logistic regression was used to identify patient and hospital factors associated with MIS utilization. RESULTS: Surgeon MIS utilization varied, with 58% of 540 surgeons performing no MIS repair. For the remaining surgeons, MIS utilization was bimodally distributed. High-utilization surgeons were unevenly distributed across region, with corresponding differences in regional MIS rate ranging from 10 to 48% (p < 0.001). MIS was used in 41% of bilateral and 38% of recurrent hernia. MIS repair was more likely with higher hospital volume and less likely for patients aged 65+ (OR 0.68, p = 0.003), black patients (OR 0.75, p = 0.045), patients with COPD (OR 0.57, p < 0.001), and patients in ASA class > 3 (OR 0.79 p < 0.001). CONCLUSIONS: MIS utilization varies between surgeons, likely driving differences in regional MIS rates and leading to guideline-discordant care for patients with bilateral or recurrent hernia. Interventions to reduce this practice gap could include training programs in MIS repair, or regionalization of care to improve MIS access.

Understanding Disparities in Surgical Outcomes for Medicaid Beneficiaries.

BACKGROUND: Few studies have evaluated whether outcome disparities between Medicaid and private insurance beneficiaries are driven by the hospital at which the patient receives care. The purpose of this study was to evaluate the effect of the hospital on surgical outcomes in Medicaid beneficiaries. METHODS: We identified 139,566 non-elderly Medicaid and private insurance beneficiaries undergoing general, vascular, or gynecological surgery between 2012 and 2017 using a statewide clinical registry in Michigan. We calculated risk-adjusted rates of complications, readmissions, emergency department (ED) visits, and post-acute care utilization using multivariable logistic regression, accounting for patient and procedural factors. We then evaluated whether, and to what extent, the hospital influenced outcome disparities between Medicaid and privately insured beneficiaries. RESULTS: Risk-adjusted rates for all outcomes were higher in Medicaid beneficiaries. For example, overall post-discharge ED visit rates were 14.3% (95% CI 13.7% to 14.9%) for Medicaid compared to 7.5% (95% CI 7.1% to 7.9%, P < 0.01) for private insurance beneficiaries. Hospital factors explained 3.9% of the observed difference in complication rates between Medicaid and private insurance beneficiaries. In contrast, hospital factors explained a greater proportion of the disparities in readmissions (30.6%), ED visits (33.0%), and post-acute care utilization (16.1%). Results were similar when restricting the study population to elective cases only. CONCLUSIONS: Hospital factors account for a significant proportion of the disparities in post-discharge resource utilization between Medicaid and private insurance beneficiaries. Policies aiming to improve the quality and equity of surgical care for Medicaid beneficiaries should focus on the post-discharge period.

The Use of Opportunistic Salpingectomy at the Time of Benign Hysterectomy.

STUDY OBJECTIVE: To delineate the use of opportunistic salpingectomy over the study period, to examine factors associated with its use, and to evaluate whether salpingectomy was associated with perioperative complications. DESIGN: A retrospective cross-sectional study (Canadian Task Force classification II-2). SETTING: The Michigan Surgical Quality Collaborative. PATIENTS: Women undergoing ovarian-conserving hysterectomy for benign indications from January 2013 through April 2015. INTERVENTIONS: The primary outcome was the performance of opportunistic salpingectomy with ovarian preservation during benign hysterectomy. The change in the rate of salpingectomy was examined at 4-month intervals to assess a period effect over the study period. Multivariate logistic regression was performed to evaluate independent effects of patient, operative, and period factors. Perioperative outcomes were compared using propensity score matching. MEASUREMENTS AND MAIN RESULTS: There were 10 676 (55.9%) ovarian-conserving hysterectomies among 19 090 benign hysterectomies in the Michigan Surgical Quality Collaborative in the study period. The rate of opportunistic salpingectomy was 45.8% (n = 4890). Rates of opportunistic salpingectomy increased over the study period from 27.5% to 61.6% (p < .001), demonstrating a strong period effect in the consecutive 4-month period analysis. Salpingectomy was more likely with the laparoscopic approach (odds ratio = 3.48; 95% confidence interval, 3.15-3.85) and among women younger than 60 years of age (odds ratio = 1.60; 95% CI, 1.34-1.92). There was substantial variation in salpingectomy across hospital sites, ranging from 3.6% to 79.9%. Salpingectomy was associated with a 12-minute increase in operative time (p < .001), but there were no differences in the estimated blood loss or perioperative complications. CONCLUSION: The rates of salpingectomy increased significantly over the study period. The laparoscopic approach and younger age are associated with an increased probability of salpingectomy. Salpingectomy is not associated with increased blood loss or perioperative complications.

Intraoperative hyperglycemia is independently associated with infectious complications after non-cardiac surgery.

BACKGROUND: Perioperative hyperglycemia and its associated increase in morbidity and mortality have been well studied in the critical care and cardiac surgery literature. However, there is little data regarding the impact of intraoperative hyperglycemia on post-operative infectious complications in non-cardiac surgery. METHODS: All National Surgery Quality Improvement Program patients undergoing general, vascular, and urological surgery at our tertiary care center were reviewed. After integrating intraoperative glucose measurements from our intraoperative electronic health record, we categorized patients as experiencing mild (8.3-11.0 mmol/L), moderate (11.1-16.6 mmol/L), and severe (≥ 16.7 mmol/L) intraoperative hyperglycemia. Using multiple logistic regression to adjust for patient comorbidities and surgical factors, we evaluated the association of hyperglycemia with the primary outcome of postoperative surgical site infection, pneumonia, urinary tract infection, or sepsis within 30 days. RESULTS: Of 13,954 patients reviewed, 3150 patients met inclusion criteria and had an intraoperative glucose measurement. 49% (n = 1531) of patients experienced hyperglycemia and 15% (n = 482) patients experienced an infectious complication. Patients with mild (adjusted odds ratio 1.30, 95% confidence interval [1.01 to 1.68], p-value = 0.04) and moderate hyperglycemia (adjusted odds ratio 1.57, 95% confidence interval [1.08-2.28], p-value = 0.02) had a statistically significant risk-adjusted increase in infectious complications. The model c-statistic was 0.72 [95% confidence interval 0.69-0.74]. CONCLUSIONS: This is one of the first studies to demonstrate an independent relationship between intraoperative hyperglycemia and postoperative infectious complications. Future studies are needed to evaluate a causal relationship and impact of treatment.

Gender differences in preference for reward frequency versus reward magnitude in decision-making under uncertainty.

Extensive research has focused on gender differences in intertemporal choices made from description in which participants must choose from multiple options that are specified without ambiguity. However, there has been limited work examining gender differences in intertemporal choices made from experience in which the possible payoffs among choice alternatives are not initially known and can only be gained from experience. Other work suggests that females attend more to reward frequency, whereas males attend more to reward magnitude. However, the tasks used in this research have been complex and did not examine intertemporal decision-making. To specifically test whether females are more sensitive to reward frequency and males are more sensitive to reward magnitude on intertemporal decisions made from experience, we designed a simple choice task in which participants pressed a response button at a time of their own choosing on each of many trials. Faster responses led to smaller, but more frequent rewards, whereas slower responses led to larger, but less frequently given rewards. As predicted, females tended to respond quicker for more certain, smaller rewards than males, supporting our prediction that women attend more to reward frequency whereas men attend more to reward magnitude.

Population-based Assessment of Intraoperative Fluid Administration Practices Across Three Surgical Specialties.

OBJECTIVE: To assess the variation in hospitals' approaches to intraoperative fluid management and their association with postoperative recovery. BACKGROUND: Despite increasing interest in goal-directed, restricted-volume fluid administration for major surgery, there remains little consensus on optimal strategies, due to the lack of institution-level studies of resuscitation practices. METHODS: Among 64 hospitals in a state-wide surgical collaborative, we profiled fluid administration practices during 8404 intestinal resections, 22,854 hysterectomies, and 1471 abdominopelvic endovascular procedures. We computed intraoperative fluid balance, accounting for patient morphometry, crystalloid, colloid, blood products, urine, blood loss, duration, and approach. We stratified hospitals by average fluid balance quartile, and compared patterns across disciplines and associations with risk-adjusted postoperative length of stay (pLOS). RESULTS: There was wide variation in fluid balance between hospitals (P < 0.001, all procedures), but significant within-hospital correlation across operations (Pearson rho: intestinal-hysterectomy = 0.50, intestinal-endovascular = 0.36, hysterectomy-endovascular = 0.54, all P < 0.05). Highest fluid balance hospitals had significantly longer adjusted pLOS than lowest balance hospitals for intestinal resection (6.5 vs 5.7 d, P < 0.001) and hysterectomy (1.9 vs 1.7 d, P < 0.001), but not endovascular (2.1 vs 2.3 d, P = 0.69). Risk-adjusted complication rates were not associated with fluid balance rankings. CONCLUSIONS: Hospitals' approaches to intraoperative fluid administration vary widely, and their practice patterns are pervasive across disparate procedures. High fluid balance hospitals have 12% to 14% longer risk-adjusted pLOS for visceral abdominal surgery, independent of patient complexity and complications. These findings are consistent with evidence that isovolemic resuscitation in enhanced recovery protocols accelerates recovery of bowel function.

Optimizing Value of Colon Surgery in Michigan.

OBJECTIVE: To assess the value of bundling perioperative care measures in colon surgery. BACKGROUND: Surgical site infections (SSI) in colectomy are associated with increased morbidity and cost. Perioperative care bundling has been designed to improve processes of care surrounding colectomy operations. METHODS: Retrospective cohort study performed by the Michigan Surgical Quality Collaborative (MSQC) of patients who underwent elective colon surgery from 2012 to 2015. We identified 3,387 patients in the MSQC database who underwent colon surgery. Of these cases, 332 had associated episodic cost data. RESULTS: High compliance (3-6 bundle elements) and low compliance (0-2 bundle elements) had a risk-adjusted SSI rate of 8.2% (95% confidence interval, CI, 7.2-9.2%) and 16.0% (95% CI, 12.9-19.1%), respectively (P < 0.01). When compared with low compliance, the high compliance group had an absolute risk reduction of 3.6% (P < 0.01), 2.9% (P < 0.01) and 1.3% (P < 0.01) for SSI rates in superficial space, deep space, and organ space, respectively. Low compliance had an average episodic cost of $20,046 (95% CI, $17,281-$22,812) whereas high compliance had an episodic cost of $15,272 (95% CI, $14,354-$16,192). This showed a $4,774 (95% CI, $1,859-$7,688) and 23.8% cost reduction (P < 0.01). Facility base payments decreased 14.8% ($13,444; $11,458), professional payments decreased 43.9% ($5,180; $2,906), and other payments decreased 36.2% ($1,422; $908). CONCLUSIONS: A colectomy perioperative care bundle in Michigan is associated with improved value of surgical care. We will expand efforts to implement perioperative care bundles in Michigan to improve outcomes and reduce costs.