Browsing by Issue Date, starting with "2024-09"
Now showing 1 - 10 of 13
Results Per Page
Sort Options
- Intelligent PPG-based Heart Rate Signal Analysis for Car Drivers MonitoringPublication . Baiense, João Pedro; Eerdekens, Anniek; Schampheleer, Jorn; Deruyck, Margot; Pires, Ivan Miguel; Velez, Fernando JoséThis research aims to contribute to enhancing road safety through the development and exploration of an intelligent wristbandbased health monitoring solution for car drivers. It focuses on using various sensors, such as the photoplethysmogram (PPG) and an accelerometer, to accurately estimate the drivers’ heart rate. The primary goal was to create a robust and accurate model capable of real-time heart rate estimation from PPG signals, with the potential to improve the effectiveness of Internet of Medical Things (IoMT) applications in the healthcare sector. The study delves into the multiple processing steps involved in improving the quality of data to make it suitable for efficient processing by the deep learning model, encompassing data analysis, signal interpretation, and applying diverse techniques such as filters, data shifting, and data manipulation. The research integrated the leave-one-session-out (LOSO) cross-validation technique for model training and evaluation alongside fine-tuning hyperparameters to optimize model performance and efficiency. The achieved Mean Absolute Error (MAE) of 3.450 ± 1.324 bpm and Mean Squared Error (MSE) of 69.50 ± 93.57 bpm2 represent notable outcomes, resulting in a 54.9% improvement in MAE from the original study. Additionally, the research integrated the model into a user-friendly mobile application, visually presenting the results and enabling users to examine their health status in real-time. These findings highlight the significance of eticulous data analysis and processing in wearable device applications and the high accuracy of the proposed model.
- Segurança, Defesa e a Paz: Educação para a Cidadania no Currículo Escolar em PortugalPublication . Albernaz, V. B.O presente estudo tem como objetivo refletir sobre quais as estratégias educativas para a educação e para a cidadania dos jovens voltadas para a segurança, defesa e a paz no ensino secundário em Portugal. Buscamos debater sobre as diferenças de adoção pedagógica entre um Estabelecimento Militar de Educação e um Estabelecimento Regular de ensino e refletir sobre a importância na adoção de uma Unidade Curricular-UC voltada para o ensino de Segurança, Defesa e Paz nos estabelecimentos regulares de ensino. Metodologicamente, a pesquisa resulta de uma pesquisa bibliográfica e documental, visando delimitar os referenciais teóricos. Em seguida aborda as leis e diretrizes que legitimam a educação para a cidadania voltada para a segurança, defesa e a paz. Por último realiza a comparação dos planos curriculares das seguintes escolas: Colégio Militar em Lisboa e Escola Secundária Campos Melo, na Covilhã.
- Towards a Framework for System and Attack Modelling and Mapping of Requirements and Technology for the Internet of ThingsPublication . Sequeiros, João Bernardo Ferreira; Inácio, Pedro Ricardo MoraisThe proliferation of Internet of Things (IoT) devices has been expanding several domains, offering unprecedented connectivity and convenience. However, this surge in interconnected devices has brought forth significant security challenges, as constrained budgets and development time leave security in a secondary role, or even non-existent. This is compounded upon by small design and development teams, where security expertise is reduced and lacking, creating a landscape of IoT systems that are unsecured and ripe for attack by malicious actors. The data gathered by these devices, their general lack of security, and the possibility of serving ans entry points to otherwise more secure systems, makes them increasingly tempting targets for exploration and exploitation. This thesis attempts to bridge the gap of aiding in the secure IoT system development, by approaching the issue of security in IoT from a standpoint of low knowledge and/or low expertise in IoT security. The first step towards the main goal is the extensive survey of existing IoT architectures and modeling tools, to aid in identifying the main challenges in secure IoT development and what can be improved or built upon. The second phase advances upon what was surveyed, by proposing an IoT system model that encompasses a large set of IoT ecosystems, and that embeds security in its essence, by identifying, for each system component, what are its critical security requirements, and what are the most attractive targets for an attacker on the given component. This model is complemented by the creation of an attack taxonomy, that attempts to take the most common attacks on IoT, and identifying where in the system those attacks may occur. To further aid the development process and provide a practical substrate to the Doctor of Philosophy (degree) (Ph.D.) work, an attack modeling tool named Attack Trees for IoT (ATIoT) is presented as a means to identify, starting from a system description given through a direct answer questionnaire, the attacks the system may be more susceptible to, providing the user with a set of attack trees, together with detailed node descriptions, of the identified attacks for the described system. Joining ATIoT, other existing tools are mapped to the proposed model, to further aid in identifying where security requirements, best practices, guidelines, security mechanisms and potential threats in an IoT system should be applied or can be found, further enhancing the usefulness of such tools. Motivated by the profound transformation that Artificial Intelligence (AI) is causing in the technological world, and the always fast advancing security area, a series of experiments of applying different AI mechanisms to the developed tools are also detailed herein. They specifically concern the application of classification models to the elicitation of security requirements, and the use of Large Language Models (LLMs) for identifying potential attacks from a textual system description. The thesis presents the results of these experiments, which show the promise of applying such methodologies to the process of security engineering. Main conclusions include achieving the goal of creating a panoply of mechanisms and tools that aid the development of secure IoT systems, that were designed towards being used by developers with low or no security background and expertise. It was also concluded that AI methods can aid in the maintaining of such tools and mechanisms, ensuring their validity in a longer time period, a challenge always present in fast-paced, always evolving areas.
- Influence of aluminum nanoparticles in alternative fuel: Single droplet combustion experiments and modelingPublication . Ferrão, Inês; Mendes, Tomás; Mendes, Miguel; Moita, A. S.; Silva, A. R. R.In this work, the effect of adding aluminum nanoparticles on hydrotreated vegetable oil was investigated experimentally and numerically in terms of nanofuel stability and single droplet combustion. The purpose is to understand the phenomena related to isolated droplet combustion when metallic particles are added to a liquid biofuel. Falling droplet combustion experiments were conducted in a drop tube furnace at two different furnace temperatures (800 C and 1000 C) using a high-speed camera coupled with a high magnification lens to investigate the droplet size evolution as disruptive burning phenomena. In numerical terms, a simplified macroscopic model was developed to predict the burning behavior of isolated nanofuel droplets, considering hexadecane as a surrogate fuel for the biofuel. The results reveal that adding nanoparticles resulted in a departure from the -law. Moreover, an increase in the overall droplet burning rate was observed, and according to the numerical results, nanoparticle radiation absorption is the responsible mechanism. Micro-explosions occurred for all nanofuels, and this disruptive burning behavior substantially influenced the droplet lifetime.
- Thermal properties of electrical arc furnace slag based materials obtained by accelerated carbonationPublication . Cristino, Luciana Sucupira; Gomes, João Paulo de CastroReducing dependence on fossil fuels and harnessing renewable energy are imperative to facing the current climate emergency and mitigating problems related to pollutants. This thesis focuses on the analysis of the microstructure and thermal properties of mortars manufactured with 100% electric arc furnace slag (EAF-slag) for passive solar energy capture, aiming to contribute to sustainable energy solutions. The first phase involved a comprehensive review of recent civil engineering research on solar thermal energy storage, highlighting the potential of energy harvesting devices. In addition, it delved deeper into the investigation of accelerated carbonation materials used both in research environments and in the construction sector. The subsequent step evaluated the thermal capacity of the EAF-slag through differential scanning calorimetry (DSC). The results indicated that the EAF-slag binders exhibited consistent and minimal changes in heat flux responses at various temperature rates, contrasting with the irregular and more significant variations observed in the Portland cement-based binders. The DSC results emphasized the potential of EAF-slag in developing materials with thermal properties. The third stage analyzed the thermal properties, microstructure and compressive strength of 100% EAF-slag mortars, with and without biochar. The incorporation of biochar led to a reduction in the thermal conductivity of the specimens. However, all EAF-slag specimens obtained results that surpass conventional Portland cement specimens in thermal conductivity. EAF-slag mortars demonstrated favorable thermal properties in all tests carried out. The thermal expansion of EAF-slag mortars was slightly more than twice that of Portland cement (PC) mortars. The EAF-slag mortar sample maintained a higher temperature than the PC mortar sample. The material with particle size composition ranging from 1 mm to 2 mm and 100% EAF slag without biochar showed the most promising results of all tests of passive solar energy utilization in the construction industry. These findings highlight a potential for 100% EAF-slag materials in passive solar thermal applications. Their superior thermal conductivity, substantial thermal capacitance, gradual heat absorption and heat release characteristics, and resilience to the effects of thermal energy position them as materials that perform well in maintaining mechanical stability even under extreme summer conditions. This research highlights the feasibility of 100% EAF-slag carbonated materials for construction, offering a sustainable solution that mitigates the environmental impacts associated with waste and conventional passive solar thermal energy storage. This study represents an advancement toward innovative and sustainable practices in civil engineering and construction. The analyzed material can be applied to facades, roofs, and pavements in areas with high solar exposure and elevated temperatures.
- Essays on electricity market price dynamics: the effects of restructuring the generation mix and energy transition policiesPublication . Macedo, Daniela Pereira; Marques, António Manuel CardosoProducing energy from fossil energy sources is the giant behind the climate change. The energy transition is fostering the massive integration of intermittent Renewable Energy Sources (RES-I) to reduce carbon dioxide and other greenhouse gas emissions. The integration of RES-I, such as wind and solar photovoltaic (PV) power, in electricity markets entails great challenges mainly because of (i) intermittent production levels; and (ii) nearly zero marginal production costs. The inherent features of RES-I are being claimed of decreasing the wholesale electricity price, also known as the Merit-Order Effect (MOE). Meanwhile, the volatility of the wholesale electricity prices was also found to be strongly affected by electricity production levels from RES-I. This thesis is focused on analyzing the electricity market price dynamics in European countries and is divided in two parts. The first part consists of four essays, where the MOE and the behaviour of the wholesale electricity price is assessed in detail. The second part is composed by two essays, that discuss the potential consequences of energy transition policies aiming the reduction of the dependency in fossil fuels. The first part assesses, in the first essay, the impact in behaviour of the volatility of the Portuguese wholesale electricity price of the electricity produced from wind and solar PV power, by analysing two different samples. The long-sample covers a period where both wind and solar PV power incurred significant development levels, although the deployment of wind power stands out. Meanwhile, the small sample is focused in analysing the significant deployment of solar PV power. The main findings of this essay suggest that the the behaviour of the volatility of the electricity price, per-si, is less persistent in short-sample. This could be related to the knowledge acquired by market participants regarding the ramp-up phase of wind power, which makes them less susceptible of making short-sighted decisions in the speed-up period of the solar PV power. Furthermore, the electricity produced from wind and solar PV power revealed to increase and decrease the volatility of the wholesale electricity price, respectively. The differing production patterns of wind and solar PV power could be behind the reasoning for their divergent impacts on the volatility of the wholesale electricity price. Therefore, in the second and third essays, the behaviour of the wholesale electricity price is analysed for each hour of the day, by also considering the role of external factors, namely electricity imports and exports. Two different electricity markets, i.e., the Nord Pool and the Iberian, namely by focusing on Sweden and Spain, respectively, were analysed. The results of these two electricity systems, which have different pricing mechanisms (namely, zonal and uniform) and generation mix structures, were critically compared. The results of essay 2 revealed that the magnitude of the MOE was stable in Sweden during the 24 hours of the day. Meanwhile, in Spain, the behaviour of the MOE was found to vary significantly during the day. In fact, the differing behaviours of the MOE are related with the baseload and backup strategies used in each electricity system. The Swedish electricity system, has high production levels from nuclear power – with low production costs - and it belongs to an electricity market with great production levels of hydro power. However, in the Spanish electricity system, natural gas is the major backup energy source, which entails higher production costs. Another revealing finding of these two essays is the impact of the electricity flow in the behaviour of the wholesale electricity price. In Spain, electricity imports and exports reduce both the mean and volatility of the electricity price, in most hours of the day, as evidenced in the third essay. Meanwhile, in Sweden, the electricity flow, with neighbouring countries, appear to augment the volatility of electricity prices, mainly during peak hours of electricity consumption. This could be related with congestion in transmission lines. In fact, both zonal and uniform pricing mechanism reveal inneficiencies. In the fourth essay, where the main advantages and disadvantages of pricing mechanisms – zonal, uniform and nodal - are discussed, the potential inefficiencies in the redispatch mechanism, in the zonal and uniform pricing mechanisms, are warned. Backup strategies seem to have a prominent role in ensuring energy security. However, recent energy policies appear to underestimate the flexibility needs in electricity markets by strongly betting on displacing fossil energy sources. The second part of this thesis analyses, in the fifth essay, the role of the natural gas in the pre- and post-decommission period of coal power plants, in Portugal. The results revealed that the electricity produced from natural gas explains a greater percentage of the variance in electricity price after the decommissioning of coal power plants. In fact, the energy transition seems not to be ready to displace fossil energy sources from the electricity markets. In the last essay of this thesis, the impact of investment in research, development and demonstration (RD&D) in fossil energy sources and RES in retail electricity prices (both industrial and household) is analysed for 10 European countries. Additional investments RD&D in fossil energy sources is likely to decrease retail electricity prices (both industrial and households), while RD&D investments in RES increase household electricity prices. In short, this thesis provides insightful guidelines for designing energy policies considering the sustainable diversification of the electricity generation mix during the energy transition. The role of the electricity flow and resilient backup strategies were identified as potential strategies to ensure the resilience, as well as the reliability of electricity markets.
- Aplicação de Patient-Reported Outcome Measures (PROMs) em pacientes com Hipertensão Arterial – Revisão SistemáticaPublication . Fonseca, Daniel Filipe Silva; Almeida, Anabela Antunes de; Sousa, Miguel Castelo Branco Craveiro deIntrodução: A Hipertensão Arterial (HTA) é uma doença com elevada prevalência a nível mundial, sendo que para o seu tratamento é essencial a adesão do paciente às alterações de estilo de vida e à terapêutica farmacológica. Neste contexto de cuidados centrados no paciente, os Patient-Reported Outcome Measures (PROMs) têm particular interesse, por obter informações sobre vários resultados da saúde da perspetiva do paciente (PRO), o que permite melhorar os seus cuidados de saúde. Objetivo: Identificar quais os PROMs genéricos ou específicos de HTA que estão a ser aplicados para estudar doentes de HTA. Métodos: Para esta revisão sistemática da literatura foram utilizadas as bases de dados PubMed, B-on e Web of Science. Foram selecionados artigos escritos em inglês, espanhol e português, com publicação entre 23 de março de 2019 e 23 de março de 2024. A data da última pesquisa foi 23 de março de 2024. Foram incluídos artigos que aplicassem PROMs genéricos ou específicos de HTA a adultos com HTA, e excluídos protocolos de ensaios clínicos e estudos de desenvolvimento e/ou validação de PROMs. Para sintetizar os dados extraídos dos estudos foi elaborada uma tabela no Excel. Resultados: Foram obtidos 728 artigos da pesquisa nas bases de dados. Após remoção de duplicados (n=503), foram submetidos a triagem do título e resumo 225 artigos, com exclusão de 118 artigos nesta fase. Foram procurados 107 artigos para recuperação integral, resultando em 85 artigos. Deste número foram excluídos 77 artigos, por não cumprirem os critérios de elegibilidade, resultando num número final de 8 artigos. Estes artigos foram publicados em países diferentes, com tipos de estudos diferentes e tamanhos de amostra variáveis entre 140 a 1225. Foi identificado um total de 19 PROMs, incluindo um PROMs específico da HTA, o MINICHAL, e os seguintes PROMs genéricos: 6 domínios do PROMIS; EQ-5D-3L e EQ-5D-5L, com o EQ-VAS aplicado isoladamente também; SF-36 e SF-12; MMAS-8; TSQM 1.4; PHQ-8; GHQ-12; PSS; STAI; BDI-II; HADS. Quanto aos domínios avaliados, houve um foco na saúde mental, seguido da QVRS e da adesão à medicação. Conclusão: Esta revisão sistemática da literatura identificou um número variado de PROMs que avaliam diversos domínios, com destaque para o MINICHAL e os questionários dos grupos PROMIS, EuroQOL e SF-36/SF-12. Tendo em conta o número de estudos incluídos, é necessária mais investigação nesta área para esclarecer quais os instrumentos mais adequados, com desenvolvimento, validação e aplicação de mais PROMs específicos de HTA.
- Quantificação e potencial valorização de resíduos de Policloreto de Vinila (PVC) utilizados nos blocos operatórios hospitalaresPublication . Quaresma, Gabriela Lima de Oliveira; Campos, Luís Manuel Barreto; Salvador, Mário Rui Arrifano; Oliveira, Maria Elisa Cairrão RodriguesIntrodução: Atualmente, não existem dúvidas quanto ao contributo e impacto que a humanidade causou no planeta. As alterações climáticas são uma das maiores ameaças à Saúde da População, por isso é imperativo que os próprios serviços de saúde sejam promotores de estratégias de mitigação e redução do seu impacto no ambiente (e consequentemente na saúde). Sendo os resíduos um importante fator negativo ambiental dos Hospitais, a sua gestão pode e deve ser alvo de diversas estratégias de melhoria. A nível global é incentivada a realização da reciclagem, contudo a mesma é mais complicada e controversa para os plásticos utilizados nos hospitais. O policloreto de vinila (PVC) é identificado como o polímero mais utilizado, enquanto os blocos operatórios são uma das principais fontes de resíduos. Por estes motivos, o presente estudo dá primazia ao PVC utilizado nas cirurgias em bloco operatório em Portugal, quantificando-o e refletindo sobre a sua gestão. Materiais e Métodos: Num hospital, durante 49 dias, foram registados os números de cirurgias realizadas e a quantidade de PVC, previamente selecionado, descartado por dia em todo o bloco operatório. Foram ainda, consultados os números de cirurgias realizadas em bloco operatório, no ano de 2022, em todo o Sistema de saúde. Resultados: No período definido, realizaram-se 1 603 cirurgias e foi descartado cerca de 320,7 Kg de PVC, dando uma média de 0,2 Kg de PVC/ por cirurgia. Considerando o total de cirurgias realizadas em 2022, pode induzir-se que cerca de 218 240 Kg de PVC (~21,82 t) foi utilizado e descartado. Conclusões: Apesar de apresentar algumas limitações, este estudo demonstra um valor significativo de PVC a ser descartado e com grande impacto ambiental associado. Ao abrigo das recomendações atuais, importa compreender se este PVC, cumpre na sua constituição as normas europeias, se parte deste pode ser substituído por outras alternativas seguras e menos tóxicas e, ainda, se a sua gestão pode ser otimizada para cumprir com os objetivos ambientais. Reforça-se também a importância da revisão do enquadramento legislativo aplicado em Portugal e do empenhamento dos Profissionais de saúde.
- Vessel passivation strategies to reduce vessel pickingPublication . Coelho, João Pedro Rodrigues; Vaz, Álvaro Frederico CamposIn recent decades, the paper industry has faced several challenges, both in terms of decarbonisation of the industrial sector and in terms of innovation and concomitant evolution of the digital era. One of the problems associated with the paper industry, and in particular the study case, Eucalyptus globulus (hardwood), is the presence of vessel elements in the wood structure. This problem stands out not in production (paper industry) but in the use (consumer) of the final product. In the case of printing from paper produced with this pulp, the poor adhesion of these elements to the surface of the paper can cause them to come loose and contaminate the printing system, a phenomenon called vessel picking and ink refusal. It is a problem commonly found in printing industries that need to make large quantities of prints and associated with the paper industry for the production of paper. During the printing process, this phenomenon occurs due to the stickiness of the inks involved in the printing process and can cause vessel elements torn from the paper surface to contaminate the printing machine circuit. This contamination can result in a drop in production due to the stopping of printing machines for cleaning, which can result in increased costs. Although it is not a directly felt problem in the paper industry, there is a continuous need to optimize the characteristics of a product, reducing the rate of complaints due to this problem. There is also a need to follow the evolution of the digital era and technologies, including printing technologies that increasingly print faster and with more colours, posing other types of challenges to the paper structure while at the same time accompanying the decarbonisation of the sector. This thesis aimed to understand the phenomenon allowing the creation of papers with a low level of vessel picking and following the studies carried out over the last decades on the subject, some approaches to this problem were attempted. The physical separation of vessel elements was attempted, using the Jacquelin method and also the Britt-Jar method. Some adaptations were made to separation methods (Britt-Jar) and others were created for the same purpose (adapted Strainer). The objective was to create a pure vessel fraction (>90%) to be able to use different analytical means and better understand the differences in behaviour between fibres and vessels, and to create a pulp fraction sufficiently rich in vessels to enable the vessel picking study. Morphological studies were carried out on the characteristics of the pulp and after achieving satisfactory separation levels (>90%) it was possible to carry out more concrete studies on the surface and global chemistry of the vessel elements and fibres. It was also possible to advance two treatment hypotheses, mechanical and enzymatic. With these studies it was possible to discover similarities and differences that could justify the different interaction between the elements (fibres and vessels) and thus try to better understand the vessel picking effect. It was also possible to perceive the effect of the treatments on the different pulp elements. The results reveal differences between vessels and fibres and point to a greater hydrophobicity of the vessels in relation to fibres (μ-FTIR spectrum with differences in the peak relative to the CH bonds and the COC ether group; it is possible that the presence of a higher concentration of hydrocarbons may be related to the greater hydrophobicity shown by the vessels, in agreement with surface free energy values, where the vessels present a higher dispersive/polar energy ratio, and with the higher values of water contact angle for the vessels (more hydrophobic)), a higher content of lignin and extractives in the vessels (low O/C content in XPS and EDX observed in the vessels can be explained by a higher content of lignin and extractives), a higher content of hemicelluloses in the vessels (having a higher content of total acids and hexenuronic acids) and a greater porosity for the vessels in relation to fibres (vessels with a higher content of mesopores and lower content of micropores). The use of enzymatic treatments revealed to have a positive effect on some of the characteristics presented by fibres and vessels (reduction in hemicellulose content and superficial reduction in the content of extractives and hemicelluloses) and also on the selectivity of enzyme action (greater effect on vessels, probably due to difference in porosity). In this work, paper with different quantities of vessels was also simulated and treatments were carried out on them. The effect of beating was studied, the effect of two enzymes (xylanase and an enzymatic cocktail containing cellulase and laccase) and the two treatments simultaneously were studied. Beating proved to be the most effective method in reducing vessel picking (>90%), although both enzymes, with greater relevance for the enzymatic cocktail, showed some effectiveness (vessel picking decrease: xylanase ≈ 38%; enzymatic cocktail ≈ 53%). Enzymatic treatments mainly revealed changes in the behaviour of the vessels and consequently in their integration into the paper structure. A preferential attack on the vessels was detected, probably due to the greater porosity of the vessels; there was a consequent increase in porosity with the enzymatic treatment, where the effect was more pronounced in the vessels; reduced hydrophobicity, proven by water contact angle measurements as well as by the increase in the polar component of the sample’s surface energy. However, the combination of the two methods proved to be the most effective methodology (>91%), and there may be a balance between beating and the use of enzymes, resulting in a reduction in operating costs. Within the tests carried out, enzymatic tests were also carried out directly on a fraction of vessels, which revealed an effectiveness of 94% in reducing vessel picking. In short, the problem of vessel picking can be controlled through beating, which is not a 100% effective solution. Enzymatic treatments improve the beating effect, proving to be efficient in terms of reducing vessel picking, however, it is necessary not to neglect side effects in the tensile properties. From the point of view of the paper production industry, when subjected to a raise in vessel problems, enzymatic treatments should be considered, before beating, presenting a good solution to mitigate the vessel picking problem.
- Libertação Percutânea do Dedo em Gatilho: Relevância da Ecografia na Intervenção CirúrgicaPublication . Coelho, Rúben da Silva; Lopes, Cláudia Manuela Silva SantosIntrodução: O dedo em gatilho caracteriza-se por dor, rigidez e sensação de bloqueio na movimentação do(s) dedo(s) afetado(s). A técnica percutânea da libertação do dedo em gatilho destaca-se por ser menos invasiva e com uma recuperação mais rápida em comparação com a cirurgia aberta, embora estejam relatadas possíveis riscos de lesão do nervo digital e, por vezes, libertações incompletas da polia A1. A ecografia foi integrada neste procedimento com o intuito de minimizar as complicações descritas, uma vez que permite a visualização das estruturas anatómicas e ajuda a orientar os instrumentos cirúrgicos utilizados. Esta revisão pretende concluir se a cirurgia percutânea ecoguiada é uma abordagem com melhores outcomes quando comparada com a libertação percutânea sem ecografia. O objetivo principal foi comparar a eficácia da técnica na resolução do gatilho, evolução da dor e complicações, e os objetivos secundários avaliados foram o grau de satisfação dos pacientes e o tempo de recuperação para as AVDs e/ou trabalho. Métodos: Foi realizada, a sete e a 14 de junho de 2024, uma pesquisa e recolha da literatura sobre a cirurgia de libertação percutânea do dedo em gatilho, seguindo o diagrama das Guidelines PRISMA 2020. Foram utilizadas as bases de dados PubMed, Scopus, Biblioteca Virtual en Salud (BVS) - coordenada pelo BIREME/OPAS/OMS, sendo a LILACS a sua principal base de dados, recorrendo à seguinte equação de pesquisa: (((trigger finger) OR (trigger digit) OR (trigger thumb)) AND ((percutaneous) OR (minimally invasive))) NOT ((cadaver) OR (open)). Das três bases de dados, foram recolhidos e importados para a aplicação Zotero todos os resultados da pesquisa. Com base na estratégia PICO, foram incluídos os estudos que abordassem a técnica percutânea da libertação da polia A1, exceto revisões sistemáticas e meta-análises. Foram excluídos também estudos em cadáveres ou que abordassem resultados de infiltrações de corticosteróides. As variáveis estudadas nesta revisão foram: libertação com sucesso de dedos em gatilho, duração do período de recuperação e follow-up, grau de satisfação do paciente, evolução da dor e complicações. Resultados: No total foram recolhidos 285 artigos, dos quais foram selecionados 21 para leitura integral. Após a leitura e análise dos dados de cada um, verifica-se que ambas as técnicas possuem altas taxas resolução da patologia, entre os 72% e os 100%. Dos 21 artigos estudados, apenas quatro comparam diretamente a técnica percutânea com e sem ecografia. Sendo estes estudos comparativos a técnica ecoguiada parece ter melhores outcomes a curto-prazo, maior taxa de resolução do gatilho e menores complicações. Todos os artigos defendem que após uma intervenção percutânea, existe uma melhora significativa no VAS score, independentemente do recurso à ecografia. Conclusão: Os resultados desta revisão não permitem concluir que a libertação percutânea da polia A1 com recurso a ecografia possui melhores outcomes do que a libertação percutânea sem recurso à mesma, pelo que mais estudos serão necessários para mostrar a superioridade de uma técnica em relação a outra.