RESUMEN
A well-functioning placenta is critical for healthy fetal development, as the placenta brings fetal blood in close contact with nutrient rich maternal blood, enabling exchange of nutrients and waste between mother and fetus. The feto-placental circulation forms a complex branching structure, providing blood to fetal capillaries, which must receive sufficient blood flow to ensure effective exchange, but at a low enough pressure to prevent damage to placental circulatory structures. The branching structure of the feto-placental circulation is known to be altered in complications such as fetal growth restriction, and the presence of regions of vascular dysfunction (such as hypovascularity or thrombosis) are proposed to elevate risk of placental pathology. Here we present a methodology to combine micro-computed tomography and computational model-based analysis of the branching structure of the feto-placental circulation in ex vivo placentae from normal term pregnancies. We analyse how vascular structure relates to function in this key organ of pregnancy; demonstrating that there is a 'resilience' to placental vascular structure-function relationships. We find that placentae with variable chorionic vascular structures, both with and without a Hyrtl's anastomosis between the umbilical arteries, and those with multiple regions of poorly vascularised tissue are able to function with a normal vascular resistance. Our models also predict that by progressively introducing local heterogeneity in placental vascular structure, large increases in feto-placental vascular resistances are induced. This suggests that localised heterogeneities in placental structure could potentially provide an indicator of increased risk of placental dysfunction.
Asunto(s)
Placenta , Circulación Placentaria , Simulación por Computador , Femenino , Humanos , Placenta/diagnóstico por imagen , Embarazo , Relación Estructura-Actividad , Microtomografía por Rayos XRESUMEN
OBJECTIVES: This umbrella review consolidates evidence available on empathy training, its effectiveness and design mechanisms that contribute to effectiveness. METHODS: We conducted an umbrella review (review of reviews) of empathy, compassion and person-centred communication training in healthcare published between 2018 and 2022. One reviewer screened titles, abstracts and full-text articles, with a second reviewer at full-text stage. Quality appraisal was done in duplicate. Data extraction was piloted by two reviewers and conducted by one reviewer with a quality check of all extracted data. All reviewers provided input into synthesis of results and analysis. RESULTS: Twenty-five reviews were included. We provide an overview of the definitions of empathy, compassion and person-centred communication, outcome measures used, a synthesis of findings on the mechanisms and effectiveness of training and a summary of review recommendations. CONCLUSIONS: For policy and practice, we advise the inclusion of empathic communication into the curriculum; longitudinal and sequenced learning; debriefing, targeted feedback, enabling self-reflection, deliberate practice, experiential learning; improving motivation by teaching the benefits of empathy and teaching sustainable empathy. Future research should involve patients in training and research and study the effect of targeting interventions at healthcare practitioners and patients.