RESUMO

Background: Reported data suggest that 4.2 million deaths will occur within 30 days of surgery worldwide each year, half of which are in low- and middle-income countries. Postoperative complications are a leading cause of long-term morbidity and mortality. Patients who survive and leave the hospital after surgical complications regularly experience reductions in long-term survival and functional independence, resulting in increased costs. With a high volume of surgery performed, there is a growing perception of the substantial impact of even minor enhancements in perioperative care. The Latin American Surgical Outcomes Study (LASOS) is an international, multicentre, prospective cohort study of adults submitted to in-patient surgery in Latin America aiming to provide detailed data describing postoperative complications and surgical mortality. Methods: LASOS is a 7 day cohort study of adults undergoing surgery in Latin America. Details of preoperative risk factors, intraoperative care, and postoperative outcomes will be collected. The primary outcome will be in-hospital postoperative complications of any cause. Secondary outcomes include in-hospital all-cause mortality, duration of hospital stay after surgery, and admission to a critical care unit within 30 days after surgery during the index hospitalisation. Results: The LASOS results will be published in peer-reviewed journals, reported and presented at international meetings, and widely disseminated to patients and public in participating countries via mainstream and social media. Conclusions: The LASOS may augment our understanding of postoperative complications and surgial mortality in Latin America. Clinical trial registration: NCT05169164.

RESUMO

Impulsivity has traditionally been thought to involve various behavioral traits that can be measured using different laboratory protocols. Whereas some authors regard different measures of impulsivity as reflecting fundamentally distinct and unrelated behavioral tendencies (fragmentation approach), others regard those different indexes as analogue forms of the same behavioral tendency, only superficially different (unification approach). Unifying accounts range from mere intuitions to more sophisticated theoretical systems. Some of the more complete attempts at unifying are intriguing but have validity weaknesses. We propose a new unifying attempt based on theoretical points posed by other authors and supplemented by theory and research on associative learning. We then apply these assumptions to characterize the paradigms used to study impulsivity in laboratory settings and evaluate their scope as an attempt at unification. We argue that our approach possesses a good balance of parsimony and empirical and theoretical grounding, as well as a more encompassing scope, and is more suitable for experimental testing than previous theoretical frameworks. In addition, the proposed approach is capable of generating a new definition of impulsivity and outlines a hypothesis of how self-control can be developed. Finally, we examine the fragmentation approach from a different perspective, emphasizing the importance of finding similarities among seemingly different phenomena.

RESUMO

Con el objetivo de evaluar el desarrollo del control del estímulo, seis ratas fueron expuestas a un programa de reforzamiento definido temporalmente (T = 60-s, = 0.5) en el que los subciclos tD y tΔ se correlacionaron con diferentes estímulos auditivos y probabilidades de reforzamiento de 1 y 0, respectivamente. Para tres ratas el subciclo tD siempre fue seguido del subciclo tΔ, mientras que para las ratas restantes ambos subciclos se presentaron de manera aleatoria (p = .5) dentro de la sesión. Al final del experimento, las frecuencias de respuesta de presión de la palanca fueron más altas durante tD y en presencia del estímulo que señaló dicho subciclo, que durante tΔ en todas las ratas. Los resultados indican que la disponibilidad limitada de reforzamiento de los programas definidos temporalmente no impide el control del estímulo, así como que dicho control se desarrolla sin patrones conductuales derivados de la regularidad secuencial entre los subciclos. Adicionalmente, los resultados cuestionan el posible desarrollo de una función de reforzador condicionado por parte del estímulo en el subciclo tΔ.

In order to evaluate the development of stimulus control, six rats were exposed to a temporally defined reinforcement schedule (T = 60-s, = 0.5) in which tD and tΔ were correlated with different auditory stimuli and with reinforcement probabilities of 1 and 0, respectively. For three rats, tD subcycle always was followed by tΔ subcycle, while for the remaining rats both subcycles were presented randomly (p = .5) within the session. At the end of the experiment, lever-pressing response frequencies were higher during tD and in the presence of the stimulus that signaled such subcycle than during tΔ subcycle for all rats. Results indicate that the limited-hold reinforcement in temporally defined schedules does not necessarily prevent stimulus control, and that such control develops without any behavioral pattern derived from sequential regularity between subcycles. Additionally, results call in to question the possible development of a conditioned reinforcement function by the stimulus in tΔ subcycle.

Com o objetivo de avaliar o desenvolvimento do controle do estímulo, seis ratos foram expostos a um programa de reforço definido temporalmente (T = 60-s, = 0.5) no qual os subciclos tD e tΔ se correlacionaram com diferentes estímulos auditivos e probabilidades de reforço de 1 e 0, respectivamente. Para três ratos, o subciclo tD sempre foi seguido do subciclo tΔ, enquanto, para os ratos restantes, ambos os subciclos foram apresentados de maneira aleatória (p = ,5) dentro da sessão. Ao final da experiência, as frequências de resposta de pressão da alavanca foram mais altas durante tD e em presença do estímulo que sinalizou esse subciclo do que durante tΔ em todos os ratos. Os resultados indicam que a disponibilidade limitada de reforço dos programas definidos temporalmente não impede o controle do estímulo, da mesma forma que esse controle se desenvolve sem padrões comportamentais derivados da regularidade sequencial entre os subciclos. Além disso, os resultados questionam o possível desenvolvimento de uma função de reforçador condicionado por parte do estímulo no subciclo tΔ.

Assuntos

RESUMO

Some of the most frequently used methods in the study of conditioned reinforcement seem to be insufficient to demonstrate the effect. The clearest way to assess this phenomenon is the training of a new response. In the present study, rats were exposed to a situation in which a primary reinforcer and an arbitrary stimulus were paired and subsequently the effect of this arbitrary event was assessed by presenting it following a new response. Subjects under these conditions emitted more responses compared to their own responding before the pairing and to their responding on a similar operandum that was available concurrently that had no programmed consequences. Response rates also were higher compared to responding by subjects in similar conditions in which there was no contingency (a) between the arbitrary stimulus and the reinforcer, (b) between the response and the arbitrary stimulus or (c) both. Results are discussed in terms of necessary and sufficient conditions to study conditioned reinforcement.

Assuntos

RESUMO

En todo el mundo, las embarazadas constituyen el grupo más vulnerable frente a la anemia ferropriva, debido a los aportes insuficientes de este nutriente en la dieta y a sus altos requerimientos metabólicos. No obstante, los esfuerzos encaminados al control y prevención de esta deficiencia, la prevalencia de la anemia no ha disminuido en los últimos años. La suplementación con hierro/ácido fólico constituye la principal estyrategia para el control de la anemia en el embarazo. Los mecanismos de aplicación efectiva de esta estrategia han sido revisados en los últimos años, a fin de lograr un impacto y control efectivo de la anemia de este grupo poblacional. Actualmente se propone la administración de una tableta de 200 mg/día de sulfato ferroso, lo que conlleva la presencia de efectos indeseables relacionados con dosis u frecuencia de administración del mismo. Estudios recientes ponen en evidencia que la adminsitración diaria de hierro reduce la capacidad de absorción intestinal por varios días, debido a un bloqueo mucoso por sobrecarga; mientras que la administración intermitente mejora la absorción de la dosis adminsitrada. Se realizó un estudio experimental en 90 mujeres embarazadas, sin patologías sobreañadidas, con una edad promedio de 25.8 +ó- 0.7 años, que acudieron a la consulta prenatal en el Hospital Gineco Obstétrico Isidro Ayora. Se asignaron aleatoriamente a uno de los tres esquemas de suplementación: 1) una tabla semanal; 2) dos tabletas semanales 3) una tableta diaria (UNICEF, 200 mg SO4 Fe+0.25 mg Ac. Fólico). En las madres gestantes se valoró; status de hierro al inicio y al parto; en los recíen nacidos; antropometría y status de hierro en la sangre de cordón (extremo placentario).

Assuntos