Using Systems Thinking and Complexity Theory to understand and improve Emergency Medicine: Lessons from COVID-19 in a safety net health system.

RATIONALE: COVID-19 has fundamentally changed the practice of Emergency Medicine (EM). Care delivery on the front lines has historically depended upon ostensibly reliable input-output models for staffing, supplies, policies, and therapies. Challenged by the complexity of healthcare during the pandemic, the fallibility of these reductionist models was quickly revealed. Providers and systems quickly had to reconceptualize their dependence on the wider, complex system in which healthcare operates and find adaptive solutions to rapid changes. AIMS/METHOD: This papers seeks to review and describe how Systems Thinking and Complexity Theory (ST/CT)-concepts, principles, and tools that can be used to understand and impact our constantly evolving health system-can be applied to better understand and enact change in complex settings such as during COVID-19. Some of these ST/CT are described through the real world example of the Alameda Health System Vaccine Taskforce. RESULTS: ST/CT concepts such as Unintended Consequences, Interrelationships, Emergent Behavior, Feedback Loops, and Path Dependence can help EM providers and planners understand the context in which their system operates. Key principles such as Collaboration, Iterative Learning, and Transformational Leadership can help these actors respond to current and future challenges. The integration of these concepts and principles into the Learning Health System offers a model for tying these key concepts and principles together into an adaptive, cross-sectoral organizational approach. CONCLUSION: By integrating ST/CT into the practice of EM, we can not only improve our ability to care for patients but also our capacity to understand and strengthen our wider systems of care.

Disturbance of Growth in Pediatric Patients Due to Osteomyelitis Caused by Growth Plate Infection.

Osteomyelitis, a severe bone infection, poses a multifaceted challenge to healthcare professionals. While its pathophysiology and treatment have been extensively studied, the impact of osteomyelitis on skeletal growth, particularly in pediatric patients, is an area that warrants attention. This abstract highlights the significance of understanding and managing growth disturbances in osteomyelitis, providing key findings and recommendations for clinicians. Understanding growth disturbance in osteomyelitis is essential because it can lead to lifelong consequences for pediatric patients. The infection may affect the growth plate, leading to limb length discrepancies, angular deformities, and functional impairments. These complications not only diminish the quality of life but also pose a substantial economic burden on the healthcare system. Therefore, early recognition and intervention are crucial. Key findings indicate that the risk of growth disturbances in osteomyelitis is particularly high in pediatric patients due to the vulnerability of the growth plate. Timely diagnosis, appropriate management, and targeted interventions can mitigate the long-term sequelae of growth disturbances. These include utilizing advanced imaging techniques to assess the extent of growth plate involvement, optimizing antibiotic therapy, and employing surgical techniques like epiphysiodesis, guided growth, or corrective osteotomies. Additionally, fostering a multidisciplinary approach that involves orthopedic surgeons, infectious disease specialists, and pediatric endocrinologists is vital to achieving successful outcomes. Recommendations for managing growth disturbance in osteomyelitis encompass early detection, meticulous monitoring, and a tailored treatment plan. Healthcare providers should remain vigilant for signs of growth plate involvement in osteomyelitis patients, especially in the pediatric population. A thorough evaluation, including advanced imaging and clinical assessment, is essential for accurate diagnosis. Close collaboration between specialists to address the infection and its skeletal consequences is crucial. Furthermore, patient and family education plays a pivotal role in fostering compliance with the treatment regimen. In conclusion, understanding and managing growth disturbances in osteomyelitis is paramount, particularly in pediatric patients. The implications of growth plate involvement are significant, and timely intervention is essential to prevent lifelong consequences. By implementing a comprehensive approach that combines accurate diagnosis, multidisciplinary collaboration, and patient education, healthcare professionals can enhance the quality of life and well-being of those affected by this challenging condition.

Cholesterol enriched diet suppresses ATF6 and PERK and upregulates the IRE1 pathways of the unfolded protein response in spontaneously hypertensive rats: Relevance to pathophysiology of atherosclerosis in the setting of hypertension.

Many studies have been dedicated to hypertension and hypercholesterolemia, as they are the primary conditions that influence the unfolded protein response (UPR). However, the concurrent effects of these two factors are unknown. Our research used spontaneously hypertensive rats (SHR) fed a cholesterol enriched diet (CED) as model of atherosclerosis formation to discover what effect the simultaneous actions of hypertension and hypercholesterolemia have on the UPR. The combination of hypertension and consumption of a CED (not the CED alone) caused the formation of early atherosclerotic features. Both increased expression of the CCAAT-enhancer-binding protein (CHOP) and the insulin induced gene 1 (INSIG1), which is the target gene of the sterol regulatory element-binding protein 1-c (SREBP1-c), and decreased expression of the spliced x-box binding protein1 (sXBP1) mRNA were observed in the SHR fed a CED. Cholesterol overload strongly suppressed glucose regulated protein 78 (GRP78), glucose regulated protein 94 (GRP 94), and the expression of CHOP and INSIG1 mRNA in both normotensive and hypertensive rats. Unlike other UPR factors, the sXBP1 mRNA expression was strongly downregulated in SHR fed a normal diet but upregulated in those fed a CED. The changes to UPR in the SHR fed a CED were associated with improvement of the initially impaired heart function of the rats.

Neighbourhood influence on the fourth dose of diphtheria-tetanus-pertussis vaccination.

OBJECTIVES: Using 542,159 vaccination records from children born between April 1, 2007, and March 31, 2012, in the Michigan Care Improvement Registry and data from the American Community Survey, we determine if neighbourhood-level characteristics at the Census tract level and block level are associated with low uptake of the fourth dose of diphtheria-tetanus-acellular pertussis vaccine (DTaP4). STUDY DESIGN: This study was a cross-sectional study. METHODS: We used exploratory factor analysis to determine important socio-economic factors at the Census block level and tract level. We then used generalised estimating equations to test the relationship between block- and tract-level socio-economic factors and DTaP4 uptake. RESULTS: DTaP4 coverage was 88.6% (95% confidence interval [CI]: 88.4%-88.7%) in Michigan. At the Census tract level, two factors surfaced as important for DTaP4 vaccination: 'affluence' (Cronbach's alpha = 0.88) and 'socio-economic disadvantage' (Cronbach's alpha = 0.89). At the Census block level, one factor was important: 'affluence' (Cronbach's alpha = 0.90). Affluence may relate to knowledge about medical exemptions and antivaccination sentiment, while socio-economic disadvantage may indicate limited access to healthcare resources. Children in high-affluence tracts had 1.08% lower vaccination coverage (95% CI: -1.62% to -0.55%) than children in low affluence tracts. Children in low socio-economic disadvantage tracts had 2.92% higher coverage than children in high socio-economic disadvantage tracts (95% CI: 2.58%-3.26%). CONCLUSIONS: This study articulates the need to further understand the contribution of neighbourhood-level characteristics, from both affluent and socioeconomically disadvantaged areas to low vaccination rates. Developing a better understanding of these social environmental factors will help determine useful community-level interventions to improve vaccination rates and reduce disease burden.

Complex systems thinking in emergency medicine: A novel paradigm for a rapidly changing and interconnected health care landscape.

INTRODUCTION: The specialty of emergency medicine is experiencing the convergence of a number of transformational forces in the United States, including health care reform, technological advancements, and societal shifts. These bring both opportunity and uncertainty. 21ST CENTURY CHALLENGES: Persistent challenges such as the opioid epidemic, rising health care costs, misaligned incentives, patients with multiple chronic diseases, and emergency department crowding continue to plague the acute, unscheduled care system. REDUCTIONISM AND COMPLEX SYSTEMS THINKING: The traditional approach to health care practice and improvement-reductionism-is not adequate for the complexity of the twenty-first century. Reductionist thinking will likely continue to produce unintended consequences and suboptimal outcomes. Complex systems thinking provides a perspective and set of tools better suited for the challenges and opportunities facing public health in general, and emergency medicine more specifically. IMPLICATIONS FOR EMERGENCY MEDICINE: This article introduces complex systems thinking and argues for its application in the context of emergency medicine by drawing on the history of the circumstances surrounding the formation of the specialty and by providing examples of its application to several practice challenges.

Environmental consequences of the flooding of the Bay Park Sewage Treatment Plant during Superstorm Sandy.

Failure of the Bay Park Sewage Treatment Plant (STP) during Superstorm Sandy led to adverse effects in the waters of Hempstead Bay, Long Island, NY. These appear to be related to large discharges of partially treated sewage through its primary and auxiliary outfalls. Modeled dilution discharges indicate that sewage infiltrated the bay, remaining up to 10days. Water column impacts included salinity and dissolved oxygen declines, and biological oxygen demand and nitrogen concentration increases. While the STP does not appear to have released fecal coliform, there were elevated levels of enterococci within the bay for a considerable period following the storm, probably from multiple sources. The STP's reduced functioning and associated environmental impacts, even with resilience upgrades, are not conducive to removing the bay from the list of Impaired Water Bodies. The results reinforce the need to transfer the discharge from the existing outfall to the ocean.

Anti-inflammatory and antioxidant effect of cerium dioxide nanoparticles immobilized on the surface of silica nanoparticles in rat experimental pneumonia.

A massage with the potent counter-inflammatory material, cerium dioxide nanoparticles, is promising and the antioxidant properties of CeO2 are considered the main, if not the only, mechanism of this action. Nevertheless, the elimination of ceria nano-particles from the organism is very slow and there is a strong concern for toxic effect of ceria due to its accumulation. To overcome this problem, we engineered a combined material in which cerium nanoparticles were immobilized on the surface of silica nanoparticles (CeO2 NP), which is shown to be easily removed from an organism and could be used as carriers for nano-ceria. In our study particle size was 220±5nm, Zeta-potential -4.5mV (in water), surface charge density -17.22µC/cm2 (at pH 7). Thirty-six male Wistar rats, 5 months old and 250-290g were divided into four groups: 1) control; 2) CeO2 NP treatment; 3) experimental pneumonia (i/p LPS injection, 1mg/kg); and 4) experimental pneumonia treated with CeO2 NP (4 times during the study in dosage of 0.6mg/kg with an orogastric catheter). Gas exchange and pulmonary ventilation were measured four times: 0, 1, 3 and 24h after LPS injection in both untreated and CeO2 NP-treated animals. The mRNA of TNF-α, Il-6, and CxCL2 were determined by RT-PCR. ROS-generation in blood plasma and lung tissue homogenates were measured by means of lucigenin- and luminol-enhanced chemiluminescence. Endotoxemia in the acute phase was associated with: (1) pathological changes in lung morphology; (2) increase of ROS generation; (3) enhanced expression of CxCL2; and (4) a gradual decrease of VO2 and VE. CeO2 NP treatment of intact animals did not make any changes in all studied parameters except for a significant augmentation of VO2 and VE. CeO2 NP treatment of rats with pneumonia created positive changes in diminishing lung tissue injury, decreasing ROS generation in blood and lung tissue and decreasing pro-inflammatory cytokine expression (TNF-α, Il-6 and CxCL2). Oxygen consumption in this group was increased compared to the LPS pneumonia group. In our study we have shown anti-inflammatory and antioxidant effects of CeO2 NP. In addition, this paper is the first to report that CeO2 NP stimulates oxygen consumption in both healthy rats, and rats with pneumonia. We propose the key in understanding the mechanisms behind the phenomena lies in the property of CeO2 NP to scavenge ROS and the influence of this potent antioxidant on mitochondrial function. The study of biodistribution and elimination of СеО2NP is the purpose of our ongoing study.

Anti-leukemic activity and tolerability of anti-human CD47 monoclonal antibodies.

CD47, a broadly expressed cell surface protein, inhibits cell phagocytosis via interaction with phagocyte-expressed SIRPα. A variety of hematological malignancies demonstrate elevated CD47 expression, suggesting that CD47 may mediate immune escape. We discovered three unique CD47-SIRPα blocking anti-CD47 monoclonal antibodies (mAbs) with low nano-molar affinity to human and cynomolgus monkey CD47, and no hemagglutination and platelet aggregation activity. To characterize the anti-cancer activity elicited by blocking CD47, the mAbs were cloned into effector function silent and competent Fc backbones. Effector function competent mAbs demonstrated potent activity in vitro and in vivo, while effector function silent mAbs demonstrated minimal activity, indicating that blocking CD47 only leads to a therapeutic effect in the presence of Fc effector function. A non-human primate study revealed that the effector function competent mAb IgG1 C47B222-(CHO) decreased red blood cells (RBC), hematocrit and hemoglobin by >40% at 1 mg/kg, whereas the effector function silent mAb IgG2σ C47B222-(CHO) had minimal impact on RBC indices at 1 and 10 mg/kg. Taken together, our findings suggest that targeting CD47 is an attractive therapeutic anti-cancer approach. However, the anti-cancer activity observed with anti-CD47 mAbs is Fc effector dependent as are the side effects observed on RBC indices.

Insensitivity to pain induced by a potent selective closed-state Nav1.7 inhibitor.

Pain places a devastating burden on patients and society and current pain therapeutics exhibit limitations in efficacy, unwanted side effects and the potential for drug abuse and diversion. Although genetic evidence has clearly demonstrated that the voltage-gated sodium channel, Nav1.7, is critical to pain sensation in mammals, pharmacological inhibitors of Nav1.7 have not yet fully recapitulated the dramatic analgesia observed in Nav1.7-null subjects. Using the tarantula venom-peptide ProTX-II as a scaffold, we engineered a library of over 1500 venom-derived peptides and identified JNJ63955918 as a potent, highly selective, closed-state Nav1.7 blocking peptide. Here we show that JNJ63955918 induces a pharmacological insensitivity to pain that closely recapitulates key features of the Nav1.7-null phenotype seen in mice and humans. Our findings demonstrate that a high degree of selectivity, coupled with a closed-state dependent mechanism of action is required for strong efficacy and indicate that peptides such as JNJ63955918 and other suitably optimized Nav1.7 inhibitors may represent viable non-opioid alternatives for the pharmacological treatment of severe pain.

Reproductive competency and mitochondrial variation in aged Syrian hamster oocytes.

The hamster is a useful model of human reproductive biology because its oocytes are similar to those in humans in terms of size and structural stability. In the present study we evaluated fecundity rate, ovarian follicular numbers, ova production, mitochondrial number, structure and function, and cytoplasmic lamellae (CL) in young (2-4 months) and old (12-18 months) Syrian hamsters (Mesocricetus auratus). Young hamsters had higher fertilisation rates and larger litters than old hamsters (100 vs 50% and 9.3±0.6 vs 5.5±0.6, respectively). Ovarian tissue from superovulated animals showed a 46% decrease in preantral follicles in old versus young hamsters. There was a 39% reduction in MII oocyte number in old versus young hamsters. Young ova had no collapsed CL, whereas old ova were replete with areas of collapsed, non-luminal CL. Eighty-nine per cent of young ova were expanded against the zona pellucida with a clear indentation at the polar body, compared with 58.64% for old ova; the remaining old ova had increased perivitelline space with no polar body indentation. Higher reactive oxygen species levels and lower mitochondrial membrane potentials were seen in ova from old versus young hamsters. A significant decrease in mitochondrial number (36%) and lower frequency of clear mitochondria (31%) were observed in MII oocytes from old versus young hamster. In conclusion, the results of the present study support the theory of oocyte depletion during mammalian aging, and suggest that morphological changes of mitochondria and CL in oocytes may be contributing factors in the age-related decline in fertility rates.

Highly fluorescent resorcinarene cavitand nanocapsules with efficient renal clearance.

Nanomaterial based imaging approaches hold substantial promise in addressing current diagnostic and therapeutic challenges. One of the key requirements for the successful clinical translation of nanomaterials is their complete clearance from the body within a reasonable time period preferably via the renal filtration route. This article describes the synthesis of highly fluorescent, water soluble, resorcinarene cavitand nanocapsules and demonstrates their effective renal clearance in mice. The synthesis and functionalization of nanocapsules was accomplished in a one-pot operation via thiol-ene reactions without involving self-assembly, sacrificial templates or emulsions. Water soluble resorcinarene cavitand nanocapsules obtained by this approach were covalently functionalized with Alexa Fluor 750. Highly fluorescent nanocapsules with hydrodynamic diameters of 122 nm and 68 nm and extinction coefficients of 1.3 × 10(9) M(-1) cm(-1) and 1.5 × 10(8) M(-1) cm(-1) respectively were prepared by varying the reaction conditions. The in vivo biodistribution and clearance of these nanocapsules in mice followed by whole-body fluorescence imaging showed that they were both cleared renally within a few hours. Given the inherent encapsulation capabilities of nanocapsules, the renal clearance demonstrated in this work opens up new opportunities for their theranostic applications especially for targeting and treating the urinary tract.

MFGE8 regulates TGF-ß-induced epithelial mesenchymal transition in endometrial epithelial cells in vitro.

This study investigated the role of milk fat globule-epidermal growth factor-factor 8 (MFGE8) in TGF-ß-induced epithelial-mesenchymal transition (EMT) of endometrial epithelial cells. These were in vitro studies using human endometrial epithelial cells and mouse blastocysts. We investigated the ability of TGF-ß to induce EMT in endometrial epithelial cells (HEC-1A) by assessment of cytological phenotype (by light and atomic force microscopy), changes in expression of the markers of cell adhesion/differentiation E- and N-cadherin, and of the transcription factor Snail (by immunofluorescence and immunoblotting), and competence to support embryo attachment in a mouse blastocyst outgrowth assay. We also studied the effects of E-cadherin expression in cells transfected by retroviral shRNA vectors specifically silencing MFGE8. Results demonstrated that TGF-ß induced EMT as demonstrated by phenotypic cell changes, by a switch of cadherin expression as well as by upregulation of the expression of the mesenchymal markers Snail and Vimentin. Upon MFGE8 knockdown, these processes were interfered with, suggesting that MFGE8 and TGF-ß together may participate in regulation of EMT. This study demonstrated for the first time that endometrial MFGE8 modulates TGF-ß-induced EMT in human endometrium cells.

Superstorm Sandy marine debris wash-ups on Long Island - What happened to them?

Superstorm Sandy generated huge quantities of debris in the Long Island, NY coastal zone. However, little appears to have been washed offshore to eventually be returned to Long Island's beaches as marine debris wash-ups. Information for our analysis includes debris collection statistics, very high resolution satellite images, along with wind and sea level data. Rigorous debris collection efforts along with meteorological conditions following the storm appear to have reduced the likelihood of debris wash-ups.

The Affordable Care Act: a case study for understanding and applying complexity concepts to health care reform.

RATIONALE, AIMS AND OBJECTIVES: The current health system in the United States is the result of a history of patchwork policy decisions and cultural assumptions that have led to persistent contradictions in practice, gaps in coverage, unsustainable costs, and inconsistent outcomes. In working toward a more efficient health system, understanding and applying complexity science concepts will allow for policy that better promotes desired outcomes and minimizes the effects of unintended consequences. METHODS: This paper will consider three applied complexity science concepts in the context of the Patient Protection and Affordable Care Act (PPACA): developing a shared vision around reimbursement for value, creating an environment for emergence through simple rules, and embracing transformational leadership at all levels. RESULTS AND CONCLUSIONS: Transforming the US health system, or any other health system, will be neither easy nor quick. Applying complexity concepts to health reform efforts, however, will facilitate long-term change in all levels, leading to health systems that are more effective, efficient, and equitable.

Medically-Derived (131)I as a Tool for Investigating the Fate of Wastewater Nitrogen in Aquatic Environments.

Medically derived (131)I (t1/2 = 8.04 d) is discharged from water pollution control plants (WPCPs) in sewage effluent. Iodine's nutrient-like behavior and the source-specificity of (131)I make this radionuclide a potentially valuable tracer in wastewater nitrogen studies. Iodine-131 was measured in Potomac River water and sediments in the vicinity of the Blue Plains WPCP, Washington, DC, USA. Dissolved (131)I showed a strong, positive correlation with δ(15)N values of nitrate (δ(15)NO3(-)) in the river, the latter being a traditional indicator of nutrient inputs and recycling. Surface water δ(15)NO3(-) values ranged from 8.7 to 33.4‰; NO3(-) + NO2(-) concentrations were 0.39-2.79 mg N L(-1) (26-186 µM). Sediment profiles of particulate (131)I and δ(15)N indicate rapid mixing or sedimentation and in many cases remineralization of a heavy nitrogen source consistent with wastewater nitrogen. Values of δ(15)N in sediments ranged from 4.7 to 9.3‰. This work introduces (131)I as a tool to investigate the short-term fate of wastewater nitrogen in the Potomac River and demonstrates the general utility of (131)I in aquatic research.

Characterization of secreted proteins of 2-cell mouse embryos cultured in vitro to the blastocyst stage with and without protein supplementation.

PURPOSE: To identify the secreted proteins of murine embryos grown in vitro. METHODS: Two-cell mouse embryos (n=432) were randomly allocated to culture to the blastocyst stage in protein-free and in protein-supplemented (3 % BSA) media. Proteins were separated by SDS-PAGE; bands were visualized by coomassie staining, followed by in-gel trypsin digestion and liquid chromatography-tandem mass spectrometry. RT-PCR and confocal microscopy were used to confirm gene/protein expression in blastocysts. RESULTS: Of all individually identified proteins, 34 and 23 were found in embryos cultured without and with BSA, respectively, and 20 were common. Identified proteins having an N-terminal secretory sequence or transmembrane domains located on the extracellular backbone were postulated as secreted proteins. Gene and protein expression for two selected molecules were confirmed. Functional analysis revealed over-represented processes related to lipid metabolism, cyclase activity, and cell adhesion/membrane functions. CONCLUSIONS: This study provided evidence to further characterize secreted proteins by mouse embryos grown from the 2-cell to the blastocyst stage in vitro. Because of homology between murine and human, these results may provide information to be translated to the clinical setting.

Targeting microglial activation in stroke therapy: pharmacological tools and gender effects.

Ischemic stroke is caused by critical reductions in blood flow to brain or spinal cord. Microglia are the resident immune cells of the central nervous system, and they respond to stroke by assuming an activated phenotype that releases cytotoxic cytokines, reactive oxygen species, proteases, and other factors. This acute, innate immune response may be teleologically adapted to limit infection, but in stroke this response can exacerbate injury by further damaging or killing nearby neurons and other cell types, and by recruiting infiltration of circulating cytotoxic immune cells. The microglial response requires hours to days to fully develop, and this time interval presents a clinically accessible time window for initiating therapy. Because of redundancy in cytotoxic microglial responses, the most effective therapeutic approach may be to target the global gene expression changes involved in microglial activation. Several classes of drugs can do this, including histone deacetylase inhibitors, minocycline and other PARP inhibitors, corticosteroids, and inhibitors of TNFα and scavenger receptor signaling. Here we review the pre-clinical studies in which these drugs have been used to suppress microglial activation after stroke. We also review recent advances in the understanding of sex differences in the CNS inflammatory response, as these differences are likely to influence the efficacy of drugs targeting post-stroke brain inflammation.

Health systems in context: a systematic review of the integration of the social determinants of health within health systems frameworks / Sistemas de salud en su contexto: revisión sistemática de la integración de los determinantes sociales de la salud en los marcos de los sistemas de salud

OBJECTIVE: To systematically review and analyze various ways that health systems frameworks interact with the social determinants of health (SDH), as well as the implications of these interactions. METHODS: This was a review of the literature conducted in 2012 using predetermined criteria to search three comprehensive databases (PubMed, the Cochrane Database for Systematic Reviews, and the World Bank E-Library) and grey literature for articles with any consideration of the SDH within health systems frameworks. Snowball sampling and expert opinion were used to include any potentially relevant articles not identified by the initial search. In total, 4 152 documents were found; of these, 27 were included in the analyses. RESULTS: Five main categories of interaction between health systems and SDH emerged: Bounded, Production, Reciprocal, Joint, and Systems models. At one end were the Bounded and Production models, which conceive the SDH to be outside the health system; at the other end, the Joint and Systems models, which visualize a continuous and dynamic interaction. CONCLUSIONS: Considering the complex and dynamic interactions among different kinds of organizations involved in and with the health system,the Joint and Systems models seem to best reflect these interactions, and should thereby guide stakeholders in planning for change.

OBJETIVO: Examinar y analizar sistemáticamente las diversas maneras en que los marcos de los sistemas de salud abordan las interacciones con los determinantes sociales de la salud (DSS), así como las implicaciones de estas interacciones. MÉTODOS: En el 2012, se llevó a cabo una revisión de la bibliografía mediante la adopción de criterios predeterminados para consultar tres bases de datos integrales (PubMed, la Base de Datos Cochrane de Revisiones Sistemáticas y la Biblioteca electrónica del Banco Mundial) y la bibliografía gris, en busca de artículos que incluyeran cualquier tipo de consideración de los DSS en los marcos de los sistemas de salud. Se utilizó el muestreo de bola de nieve y la opinión de expertos con objeto de incluir cualquier artículo potencialmente pertinente no detectado en la búsqueda inicial. En total, se encontraron 4 152 documentos; de estos, 27 se incluyeron en el análisis. RESULTADOS: Se observaron cinco categorías o modelos principales de interacción entre los sistemas de salud y los DSS: Vinculado, de Producción, Recíproco, Conjunto y de Sistemas. En un extremo se situaban los modelos Vinculado y de Producción, que contemplan los DSS como externos al sistema de salud; en el otro extremo, los modelos Conjunto y de Sistemas, que conciben una interacción continua y dinámica entre ellos. CONCLUSIONES: Si se tienen en cuentas las complejas y dinámicas interacciones entre los diferentes tipos de organizaciones involucradas en y con el sistema de salud, los modelos Conjunto y de Sistemas parecen reflejar mejor estas interacciones y, en consecuencia, son los que deberían guiar a los interesados directos en la planificación de los cambios.