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OBJECTIVE: Very often the performance of a Bayesian Network (BN) is affected when applied to a new target population. This is mainly because of differences in population characteristics. External validation of the model performance on different populations is a standard approach to test model's generalisability. However, a good predictive performance is not enough to show that the model represents the unique population characteristics and can be adopted in the new environment. METHODS: In this paper, we present a methodology for updating and recalibrating developed BN models - both their structure and parameters - to better account for the characteristics of the target population. Attention has been given on incorporating expert knowledge and recalibrating latent variables, which are usually omitted from data-driven models. RESULTS: The method is successfully applied to a clinical case study about the prediction of trauma-induced coagulopathy, where a BN has already been developed for civilian trauma patients and now it is recalibrated on combat casualties. CONCLUSION: The methodology proposed in this study is important for developing credible models that can demonstrate a good predictive performance when applied to a target population. Another advantage of the proposed methodology is that it is not limited to data-driven techniques and shows how expert knowledge can also be used when updating and recalibrating the model.
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Modelos Estatísticos , Humanos , Teorema de BayesRESUMO
BACKGROUND: Blood transfusion for bleeding trauma patients is a promising pre-hospital intervention with potential to improve outcomes. However, it is not yet clear which patients may benefit from pre-hospital transfusions. The aim of this study was to enhance our understanding of how experienced pre-hospital clinicians make decisions regarding patient blood loss and the need for transfusion, and explore the factors that influence clinical decision-making. METHODS: Pre-hospital physicians, from two air ambulance sites in the south of England, were interviewed between December 2018 and January 2019. Participants were involved in teaching or publishing on the management of bleeding trauma patients and had at least 5 years of continuous and contemporary practice at consultant level. Interviews were semi-structured and explored how decisions were made and what made decisions difficult. A qualitative description approach was used with inductive thematic analysis to identify themes and subthemes related to blood transfusion decision-making in trauma. RESULTS: Ten pre-hospital physicians were interviewed and three themes were identified: recognition-primed analysis, uncertainty and imperfect decision analysis. The first theme describes how participants make decisions using selected cues, incorporating their experience and are influenced by external rules and group expectations. What made decisions difficult for the participants was encapsulated in the uncertainty theme. Uncertainty emerged regarding the patient's true underlying physiological state and the treatment effect of blood transfusion. The last theme focuses on the issues with decision-making itself. Participants demonstrated lapses in decision awareness, often incomplete decision evaluation and described challenges to effective learning due to incomplete patient outcome information. CONCLUSION: Pre-hospital clinicians make decisions about bleeding and transfusion which are recognition-primed and incorporate significant uncertainty. Decisions are influenced by experience and are subject to bias. Improved understanding of the decision-making processes provides a theoretical perspective of how decisions might be supported in the future.
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Transfusão de Sangue , Tomada de Decisões , Humanos , Incerteza , Hospitais , Pesquisa QualitativaRESUMO
Importance: Bleeding is the most common cause of preventable death after trauma. Objective: To determine the effectiveness of resuscitative endovascular balloon occlusion of the aorta (REBOA) when used in the emergency department along with standard care vs standard care alone on mortality in trauma patients with exsanguinating hemorrhage. Design, Setting, and Participants: Pragmatic, bayesian, randomized clinical trial conducted at 16 major trauma centers in the UK. Patients aged 16 years or older with exsanguinating hemorrhage were enrolled between October 2017 and March 2022 and followed up for 90 days. Intervention: Patients were randomly assigned (1:1 allocation) to a strategy that included REBOA and standard care (n = 46) or standard care alone (n = 44). Main Outcomes and Measures: The primary outcome was all-cause mortality at 90 days. Ten secondary outcomes included mortality at 6 months, while in the hospital, and within 24 hours, 6 hours, or 3 hours; the need for definitive hemorrhage control procedures; time to commencement of definitive hemorrhage control procedures; complications; length of stay; blood product use; and cause of death. Results: Of the 90 patients (median age, 41 years [IQR, 31-59 years]; 62 [69%] were male; and the median Injury Severity Score was 41 [IQR, 29-50]) randomized, 89 were included in the primary outcome analysis because 1 patient in the standard care alone group declined to provide consent for continued participation and data collection 4 days after enrollment. At 90 days, 25 of 46 patients (54%) had experienced all-cause mortality in the REBOA and standard care group vs 18 of 43 patients (42%) in the standard care alone group (odds ratio [OR], 1.58 [95% credible interval, 0.72-3.52]; posterior probability of an OR >1 [indicating increased odds of death with REBOA], 86.9%). Among the 10 secondary outcomes, the ORs for mortality and the posterior probabilities of an OR greater than 1 for 6-month, in-hospital, and 24-, 6-, or 3-hour mortality were all increased in the REBOA and standard care group, and the ORs were increased with earlier mortality end points. There were more deaths due to bleeding in the REBOA and standard care group (8 of 25 patients [32%]) than in standard care alone group (3 of 18 patients [17%]), and most occurred within 24 hours. Conclusions and Relevance: In trauma patients with exsanguinating hemorrhage, a strategy of REBOA and standard care in the emergency department does not reduce, and may increase, mortality compared with standard care alone. Trial Registration: isrctn.org Identifier: ISRCTN16184981.
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Oclusão com Balão , Exsanguinação , Humanos , Masculino , Adulto , Feminino , Exsanguinação/complicações , Teorema de Bayes , Estudos Retrospectivos , Hemorragia/etiologia , Hemorragia/terapia , Aorta , Oclusão com Balão/efeitos adversos , Oclusão com Balão/métodos , Ressuscitação/métodos , Escala de Gravidade do Ferimento , Serviço Hospitalar de Emergência , Reino UnidoRESUMO
BACKGROUND: High energy pelvic ring injuries are associated with significant morbidity and mortality and can be accompanied by haemorrhagic shock following associated vascular injury. This study evaluated the causes and predictors of mortality in haemodynamically unstable pelvic fractures. METHODS: This retrospective observational study at a Major Trauma Centre reviewed 938 consecutive adult patients (≥ 18yrs) with pelvic ring injuries between December 2014 and November 2018. Patients with features of haemorrhagic shock were included, defined as: arrival Systolic BP < 90 mmHg, Base Deficit ≥ 6.0 mmol/l, or transfusion of ≥ 4 units of packed red blood cells within 24 h. RESULTS: Of the 102 patients included, all sustained injuries from high energy trauma, and 47.1% underwent a haemorrhage control intervention (Resuscitative Endovascular Balloon Occlusion of the Aorta-REBOA, Interventional Radiology-IR, or Laparotomy). These were more often required following vertical shear injuries (OR 10.7, p = 0.036). Overall, 33 patients (32.4%) died; 16 due to a head injury, and only 2 directly from acute pelvic exsanguination (6.1%). Multivariable logistic regression demonstrated that increasing age, Injury Severity Score, Abbreviated Injury Scale (AIS) Head ≥ 3 and open pelvic fracture were all independent predictors of mortality, and IR was associated with reduced mortality. Lateral Compression III (LC3) injuries were associated with mortality due to multiple organ dysfunction syndrome (MODS). CONCLUSION: Haemodynamically unstable patients with pelvic ring injuries have a high mortality rate, but death is usually attributed to other injuries or later complications, and not from acute exsanguination. This reflects improvements in resuscitative care, transfusion protocols, and haemorrhage control techniques.
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Fraturas Ósseas , Ossos Pélvicos , Choque Hemorrágico , Adulto , Humanos , Choque Hemorrágico/terapia , Choque Hemorrágico/complicações , Exsanguinação/complicações , Hemorragia/etiologia , Pelve , Ossos Pélvicos/lesões , Fraturas Ósseas/complicações , Fraturas Ósseas/cirurgia , Escala de Gravidade do Ferimento , Estudos RetrospectivosRESUMO
INTRODUCTION: The 6-hour threshold to revascularization of an ischemic limb is ubiquitous in the trauma literature, however, contemporary evidence suggests that this threshold should be less. This study aims to characterize the relationship between the duration of limb ischemia and successful limb salvage following lower extremity arterial trauma. METHODS: This is a cohort study of the United States and UK military service members injured while serving in Iraq or Afghanistan between 2003 and 2013. Consecutive patients who sustained iliac, femoral, or popliteal artery injuries, and underwent surgery to attempt revascularization, were included. The association between limb outcome and the duration of limb ischemia was assessed using the Kaplan-Meier method. RESULTS: One hundred twenty-two patients (129 limbs) who sustained iliac (2.3%), femoral (56.6%), and popliteal (41.1%) arterial injuries were included. Overall, 87 limbs (67.4%) were successfully salvaged. The probability of limb salvage was 86.0% when ischemia was ≤1 hour; 68.3% when between 1 and 3 hours; 56.3% when between 3 and 6 hours; and 6.7% when >6 hours ( P <0.0001). Shock more than doubled the risk of failed limb salvage [hazard ratio=2.42 (95% confidence interval: 1.27-4.62)]. CONCLUSIONS: Limb salvage is critically dependent on the duration of ischemia with a 10% reduction in the probability of successful limb salvage for every hour delay to revascularization. The presence of shock significantly worsens this relationship. Military trauma systems should prioritize rapid hemorrhage control and early limb revascularization within 1 hour of injury.
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Traumatismos da Perna , Lesões do Sistema Vascular , Amputação Cirúrgica , Estudos de Coortes , Humanos , Isquemia/etiologia , Isquemia/cirurgia , Traumatismos da Perna/cirurgia , Salvamento de Membro/métodos , Extremidade Inferior/irrigação sanguínea , Extremidade Inferior/cirurgia , Artéria Poplítea , Estudos Retrospectivos , Resultado do Tratamento , Estados Unidos , Lesões do Sistema Vascular/cirurgiaRESUMO
OBJECTIVE: The aim of this study was to develop and validate a risk prediction tool for trauma-induced coagulopathy (TIC), to support early therapeutic decision-making. BACKGROUND: TIC exacerbates hemorrhage and is associated with higher morbidity and mortality. Early and aggressive treatment of TIC improves outcome. However, injured patients that develop TIC can be difficult to identify, which may compromise effective treatment. METHODS: A Bayesian Network (BN) prediction model was developed using domain knowledge of the causal mechanisms of TIC, and trained using data from 600 patients recruited into the Activation of Coagulation and Inflammation in Trauma (ACIT) study. Performance (discrimination, calibration, and accuracy) was tested using 10-fold cross-validation and externally validated on data from new patients recruited at 3 trauma centers. RESULTS: Rates of TIC in the derivation and validation cohorts were 11.8% and 11.0%, respectively. Patients who developed TIC were significantly more likely to die (54.0% vs 5.5%, P < 0.0001), require a massive blood transfusion (43.5% vs 1.1%, P < 0.0001), or require damage control surgery (55.8% vs 3.4%, P < 0.0001), than those with normal coagulation. In the development dataset, the 14-predictor BN accurately predicted this high-risk patient group: area under the receiver operating characteristic curve (AUROC) 0.93, calibration slope (CS) 0.96, brier score (BS) 0.06, and brier skill score (BSS) 0.40. The model maintained excellent performance in the validation population: AUROC 0.95, CS 1.22, BS 0.05, and BSS 0.46. CONCLUSIONS: A BN (http://www.traumamodels.com) can accurately predict the risk of TIC in an individual patient from standard admission clinical variables. This information may support early, accurate, and efficient activation of hemostatic resuscitation protocols.
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Transtornos da Coagulação Sanguínea/etiologia , Aprendizado de Máquina Supervisionado , Ferimentos e Lesões/complicações , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Teorema de Bayes , Tomada de Decisão Clínica , Feminino , Humanos , Londres , Masculino , Pessoa de Meia-Idade , Valor Preditivo dos Testes , Estudos Prospectivos , Medição de Risco , Índices de Gravidade do TraumaRESUMO
OBJECTIVE: The aim of this study was to identify the effects of recent innovations in trauma major hemorrhage management on outcome and transfusion practice, and to determine the contemporary timings and patterns of death. BACKGROUND: The last 10 years have seen a research-led change in hemorrhage management to damage control resuscitation (DCR), focused on the prevention and treatment of trauma-induced coagulopathy. METHODS: A 10-year retrospective analysis of prospectively collected data of trauma patients who activated the Major Trauma Centre's major hemorrhage protocol (MHP) and received at least 1 unit of red blood cell transfusions (RBC). RESULTS: A total of 1169 trauma patients activated the MHP and received at least 1 unit of RBC, with similar injury and admission physiology characteristics over the decade. Overall mortality declined from 45% in 2008 to 27% in 2017, whereas median RBC transfusion rates dropped from 12 to 4 units (massive transfusion rates from 68% to 24%). The proportion of deaths within 24âhours halved (33%-16%), principally with a fall in mortality between 3 and 24âhours (30%-6%). Survivors are now more likely to be discharged to their own home (57%-73%). Exsanguination is still the principal cause of early deaths, and the mortality associated with massive transfusion remains high (48%). Late deaths are now split between those due to traumatic brain injury (52%) and multiple organ dysfunction (45%). CONCLUSIONS: There have been remarkable reductions in mortality after major trauma hemorrhage in recent years. Mortality rates continue to be high and there remain important opportunities for further improvements in these patients.
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Transfusão de Sangue , Hemorragia/terapia , Ressuscitação/métodos , Adulto , Feminino , Hemorragia/etiologia , Hemorragia/mortalidade , Humanos , Masculino , Pessoa de Meia-Idade , Ressuscitação/tendências , Estudos Retrospectivos , Índice de Gravidade de Doença , Sobreviventes , Fatores de Tempo , Resultado do Tratamento , Ferimentos e Lesões/complicações , Adulto JovemRESUMO
BACKGROUND: Intravenous tranexamic acid (TXA) reduces bleeding deaths after injury and childbirth. It is most effective when given early. In many countries, pre-hospital care is provided by people who cannot give i.v. injections. We examined the pharmacokinetics of intramuscular TXA in bleeding trauma patients. METHODS: We conducted an open-label pharmacokinetic study in two UK hospitals. Thirty bleeding trauma patients received a loading dose of TXA 1 g i.v., as per guidelines. The second TXA dose was given as two 5 ml (0·5 g each) i.m. injections. We collected blood at intervals and monitored injection sites. We measured TXA concentrations using liquid chromatography coupled to mass spectrometry. We assessed the concentration time course using non-linear mixed-effect models with age, sex, ethnicity, body weight, type of injury, signs of shock, and glomerular filtration rate as possible covariates. RESULTS: Intramuscular TXA was well tolerated with only mild injection site reactions. A two-compartment open model with first-order absorption and elimination best described the data. For a 70-kg patient, aged 44 yr without signs of shock, the population estimates were 1.94 h-1 for i.m. absorption constant, 0.77 for i.m. bioavailability, 7.1 L h-1 for elimination clearance, 11.7 L h-1 for inter-compartmental clearance, 16.1 L volume of central compartment, and 9.4 L volume of the peripheral compartment. The time to reach therapeutic concentrations (5 or 10 mg L-1) after a single intramuscular TXA 1 g injection are 4 or 11 min, with the time above these concentrations being 10 or 5.6 h, respectively. CONCLUSIONS: In bleeding trauma patients, intramuscular TXA is well tolerated and rapidly absorbed. CLINICAL TRIAL REGISTRATION: 2019-000898-23 (EudraCT); NCT03875937 (ClinicalTrials.gov).
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Antifibrinolíticos/farmacocinética , Hemorragia/tratamento farmacológico , Hemorragia/etiologia , Ácido Tranexâmico/farmacocinética , Ferimentos e Lesões/complicações , Antifibrinolíticos/administração & dosagem , Antifibrinolíticos/uso terapêutico , Feminino , Humanos , Injeções Intramusculares , Masculino , Pessoa de Meia-Idade , Estudos Prospectivos , Ácido Tranexâmico/administração & dosagem , Ácido Tranexâmico/uso terapêutico , Resultado do Tratamento , Reino UnidoRESUMO
OBJECTIVES: Estimating the likely success of limb revascularization in patients with lower-extremity arterial trauma is central to decisions between attempting limb salvage and amputation. However, the projected outcome is often unclear at the time these decisions need to be made, making them difficult and threatening sound judgement. The objective of this study was to develop and validate a prediction model that can quantify an individual patient's risk of failed revascularization. METHODS: A BN prognostic model was developed using domain knowledge and data from the US joint trauma system. Performance (discrimination, calibration, and accuracy) was tested using ten-fold cross validation and externally validated on data from the UK Joint Theatre Trauma Registry. BN performance was compared to the mangled extremity severity score. RESULTS: Rates of amputation performed because of nonviable limb tissue were 12.2% and 19.6% in the US joint trauma system (n = 508) and UK Joint Theatre Trauma Registry (n = 51) populations respectively. A 10-predictor BN accurately predicted failed revascularization: area under the receiver operating characteristic curve (AUROC) 0.95, calibration slope 1.96, Brier score (BS) 0.05, and Brier skill score 0.50. The model maintained excellent performance in an external validation population: AUROC 0.97, calibration slope 1.72, Brier score 0.08, Brier skill score 0.58, and had significantly better performance than mangled extremity severity score at predicting the need for amputation [AUROC 0.95 (0.92-0.98) vs 0.74 (0.67-0.80); P < 0.0001]. CONCLUSIONS: A BN (https://www.traumamodels.com) can accurately predict the outcome of limb revascularization at the time of initial wound evaluation. This information may complement clinical judgement, support rational and shared treatment decisions, and establish sensible treatment expectations.
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Algoritmos , Artérias/lesões , Artérias/cirurgia , Sistemas de Apoio a Decisões Clínicas , Extremidade Inferior/irrigação sanguínea , Extremidade Inferior/cirurgia , Adolescente , Adulto , Amputação Cirúrgica , Humanos , Extremidade Inferior/lesões , Aprendizado de Máquina , Pessoa de Meia-Idade , Estudos Prospectivos , Resultado do Tratamento , Procedimentos Cirúrgicos Vasculares , Adulto JovemRESUMO
OBJECTIVE: Vascular injury is a leading cause of death and disability in military and civilian settings. Most wartime and an increasing amount of civilian vascular trauma arises from penetrating mechanisms of injury due to gunshot or explosion. The objective of this study was to provide a comprehensive examination of penetrating lower extremity arterial injury and to characterize long-term limb salvage and differences related to mechanisms of injury. METHODS: The military trauma registries of the United States and the United Kingdom were analyzed to identify service members who sustained penetrating lower limb arterial injury (2001-2014). Treatment and limb salvage data were studied and comparisons made of patients whose penetrating vascular trauma arose from explosion (group 1) vs gunshot (group 2). Standardized statistical testing was used, with Bonferroni corrections for multiple comparisons. RESULTS: The cohort consisted of 568 combat casualties (mean age, 25.2 years) with 597 injuries (explosion, n = 416; gunshot, n = 181). Group 1 had higher Injury Severity Score (P < .05) and Mangled Extremity Severity Score (P < .0001), required more blood transfusion (P < .05), and had more tibial (P < .01) and popliteal (P < .05) arterial injuries; group 2 had more profunda femoris injuries (P < .05). Initial surgical management for the whole cohort included vein interposition graft (33%), ligation (31%), primary repair with or without patch angioplasty (16%), temporary vascular shunting (15%), and primary amputation (6%). No difference in patency of arterial reconstruction was found between group 1 and group 2, although group 1 had a higher incidence of primary (13% vs 2%; P < .05) and secondary (19% vs 9%; P < .05) amputation. Similarly, longer term freedom from amputation was lower for group 1 than for group 2 (68% vs 89% at 5.5 years; Cox hazard ratio, 0.30; P < .0001), as was physical functioning (36-Item Short Form Health Survey data; mean, 39.80 vs 43.20; P < .05). CONCLUSIONS: The majority of wartime lower extremity arterial injuries result from an explosive mechanism that preferentially affects the tibial vasculature and results in poorer long-term limb salvage compared with those injured with firearms. The mortality associated with immediate limb salvage attempts is low, and delayed amputations occur weeks later, affording the patient involvement in the decision-making and rehabilitation planning. We recommend assertive attempts at vascular repair and limb salvage for service members injured by explosive and gunshot mechanisms.
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Amputação Cirúrgica , Artérias/cirurgia , Traumatismos por Explosões/cirurgia , Procedimentos Endovasculares , Extremidade Inferior/irrigação sanguínea , Enxerto Vascular , Ferimentos por Arma de Fogo/cirurgia , Adulto , Amputação Cirúrgica/efeitos adversos , Amputação Cirúrgica/mortalidade , Conflitos Armados , Artérias/lesões , Artérias/fisiopatologia , Traumatismos por Explosões/diagnóstico , Traumatismos por Explosões/mortalidade , Traumatismos por Explosões/fisiopatologia , Bases de Dados Factuais , Procedimentos Endovasculares/efeitos adversos , Procedimentos Endovasculares/mortalidade , Humanos , Escala de Gravidade do Ferimento , Ligadura , Salvamento de Membro , Medicina Militar , Sistema de Registros , Estudos Retrospectivos , Fatores de Risco , Fatores de Tempo , Resultado do Tratamento , Reino Unido , Estados Unidos , Enxerto Vascular/efeitos adversos , Enxerto Vascular/métodos , Enxerto Vascular/mortalidade , Ferimentos por Arma de Fogo/diagnóstico , Ferimentos por Arma de Fogo/mortalidade , Ferimentos por Arma de Fogo/fisiopatologia , Adulto JovemRESUMO
INTRODUCTION: Tranexamic acid (TXA) reduces bleeding and mortality. Recent trials have demonstrated improved survival with shorter intervals to TXA administration. The aims of this service evaluation were to assess the interval from injury to TXA administration and describe the characteristics of patients who received TXA pre-hospital and in-hospital. METHODS: We reviewed Trauma and Audit Research Network records and local trauma registries to identify patients of any age that received TXA at all London Major Trauma Centres and Queen's Medical Centre, Nottingham, during 2017. We used the 2016 NICE Guidelines (NG39) which state that TXA should be given within 3 hours of injury. RESULTS: We identified 1018 patients who received TXA, of whom 661 (65%) had sufficient data to assess the time from injury to TXA administration. The median interval was 74 min (IQR: 47-116). 92% of patients received TXA within 3 hours from injury, and 59% within 1 hour. Half of the patients (54%) received prehospital TXA. The median time to TXA administration when given prehospital was 51 min (IQR: 39-72), and 112 min (IQR: 84-160) if given in-hospital (p<0.001). In-hospital TXA patients had less haemodynamic derangement and lower base deficit on admission compared with patients given prehospital TXA. CONCLUSION: Prehospital administration of TXA is associated with a shorter interval from injury to drug delivery. Identifying a proportion of patients at risk of haemorrhage remains a challenge. However, further reinforcement is needed to empower pre-hospital clinicians to administer TXA to trauma patients without overt signs of shock.
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Tempo para o Tratamento/estatística & dados numéricos , Ácido Tranexâmico/administração & dosagem , Adulto , Antifibrinolíticos/administração & dosagem , Antifibrinolíticos/farmacologia , Antifibrinolíticos/uso terapêutico , Feminino , Hemorragia/tratamento farmacológico , Hemorragia/mortalidade , Humanos , Londres , Masculino , Pessoa de Meia-Idade , Sistema de Registros/estatística & dados numéricos , Estudos Retrospectivos , Estatísticas não Paramétricas , Ácido Tranexâmico/farmacologia , Ácido Tranexâmico/uso terapêutico , Centros de Traumatologia/organização & administração , Centros de Traumatologia/estatística & dados numéricosRESUMO
Many medical conditions are only indirectly observed through symptoms and tests. Developing predictive models for such conditions is challenging since they can be thought of as 'latent' variables. They are not present in the data and often get confused with measurements. As a result, building a model that fits data well is not the same as making a prediction that is useful for decision makers. In this paper, we present a methodology for developing Bayesian network (BN) models that predict and reason with latent variables, using a combination of expert knowledge and available data. The method is illustrated by a case study into the prediction of acute traumatic coagulopathy (ATC), a disorder of blood clotting that significantly increases the risk of death following traumatic injuries. There are several measurements for ATC and previous models have predicted one of these measurements instead of the state of ATC itself. Our case study illustrates the advantages of models that distinguish between an underlying latent condition and its measurements, and of a continuing dialogue between the modeller and the domain experts as the model is developed using knowledge as well as data.
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Transtornos da Coagulação Sanguínea/terapia , Informática Médica/métodos , Algoritmos , Teorema de Bayes , Coagulação Sanguínea , Análise por Conglomerados , Tomada de Decisões , Sistemas de Apoio a Decisões Clínicas , Diagnóstico por Computador , Serviços Médicos de Emergência/organização & administração , Humanos , Erros Médicos/prevenção & controle , Informática Médica/tendências , Medição de Risco , Sensibilidade e EspecificidadeRESUMO
Complex clinical decisions require the decision maker to evaluate multiple factors that may interact with each other. Many clinical studies, however, report 'univariate' relations between a single factor and outcome. Such univariate statistics are often insufficient to provide useful support for complex clinical decisions even when they are pooled using meta-analysis. More useful decision support could be provided by evidence-based models that take the interaction between factors into account. In this paper, we propose a method of integrating the univariate results of a meta-analysis with a clinical dataset and expert knowledge to construct multivariate Bayesian network (BN) models. The technique reduces the size of the dataset needed to learn the parameters of a model of a given complexity. Supplementing the data with the meta-analysis results avoids the need to either simplify the model - ignoring some complexities of the problem - or to gather more data. The method is illustrated by a clinical case study into the prediction of the viability of severely injured lower extremities. The case study illustrates the advantages of integrating combined evidence into BN development: the BN developed using our method outperformed four different data-driven structure learning methods, and a well-known scoring model (MESS) in this domain.
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Teorema de Bayes , Sistemas de Apoio a Decisões Clínicas , Medicina Baseada em Evidências , Algoritmos , Humanos , Metanálise como Assunto , Modelos Teóricos , Lesões do Sistema VascularRESUMO
Background: Hemorrhage is the most common cause of potentially preventable death after injury. Early identification of patients with major hemorrhage (MH) is important as treatments are time-critical. However, diagnosis can be difficult, even for expert clinicians. This study aimed to determine how accurate clinicians are at identifying patients with MH in the prehospital setting. A second aim was to analyze factors associated with missed and overdiagnosis of MH, and the impact on mortality. Methods: Retrospective evaluation of consecutive adult (≥16 years) patients injured in 2019-2020, assessed by expert trauma clinicians in a mature prehospital trauma system, and admitted to a major trauma center (MTC). Clinicians decided to activate the major hemorrhage protocol (MHPA) or not. This decision was compared with whether patients had MH in hospital, defined as the critical admission threshold (CAT+): administration of ≥3 U of red blood cells during any 60-minute period within 24 hours of injury. Multivariate logistical regression analyses were used to analyze factors associated with diagnostic accuracy and mortality. Results: Of the 947 patients included in this study, 138 (14.6%) had MH. MH was correctly diagnosed in 97 of 138 patients (sensitivity 70%) and correctly excluded in 764 of 809 patients (specificity 94%). Factors associated with missed diagnosis were penetrating mechanism (OR 2.4, 95% CI 1.2 to 4.7) and major abdominal injury (OR 4.0; 95% CI 1.7 to 8.7). Factors associated with overdiagnosis were hypotension (OR 0.99; 95% CI 0.98 to 0.99), polytrauma (OR 1.3, 95% CI 1.1 to 1.6), and diagnostic uncertainty (OR 3.7, 95% CI 1.8 to 7.3). When MH was missed in the prehospital setting, the risk of mortality increased threefold, despite being admitted to an MTC. Conclusion: Clinical assessment has only a moderate ability to identify MH in the prehospital setting. A missed diagnosis of MH increased the odds of mortality threefold. Understanding the limitations of clinical assessment and developing solutions to aid identification of MH are warranted. Level of evidence: Level III-Retrospective study with up to two negative criteria. Study type: Original research; diagnostic accuracy study.
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Importance: Hemorrhage is the most common cause of preventable death after injury. Most deaths occur early, in the prehospital phase of care. Objective: To establish whether prehospital zone 1 (supraceliac) partial resuscitative endovascular balloon occlusion of the aorta (Z1 P-REBOA) can be achieved in the resuscitation of adult trauma patients at risk of cardiac arrest and death due to exsanguination. Design, Setting, and Participants: This was a prospective observational cohort study (Idea, Development, Exploration, Assessment and Long-term follow-up [IDEAL] 2A design) with recruitment from June 2020 to March 2022 and follow-up until discharge from hospital, death, or 90 days evaluating a physician-led and physician-delivered, urban prehospital trauma service in the Greater London area. Trauma patients aged 16 years and older with suspected exsanguinating subdiaphragmatic hemorrhage, recent or imminent hypovolemic traumatic cardiac arrest (TCA) were included. Those with unsurvivable injuries or who were pregnant were excluded. Of 2960 individuals attended by the service during the study period, 16 were included in the study. Exposures: ZI REBOA or P-REBOA. Main Outcomes and Measures: The main outcome was the proportion of patients in whom Z1 REBOA and Z1 P-REBOA were achieved. Clinical end points included systolic blood pressure (SBP) response to Z1 REBOA, mortality rate (1 hour, 3 hours, 24 hours, or 30 days postinjury), and survival to hospital discharge. Results: Femoral arterial access for Z1 REBOA was attempted in 16 patients (median [range] age, 30 [17-76] years; 14 [81%] male; median [IQR] Injury Severity Score, 50 [39-57]). In 2 patients with successful arterial access, REBOA was not attempted due to improvement in clinical condition. In the other 14 patients (8 [57%] of whom were in traumatic cardiac arrest [TCA]), 11 successfully underwent cannulation and had aortic balloons inflated in Z1. The 3 individuals in whom cannulation was unsuccessful were in TCA (failure rate = 3/14 [21%]). Median (IQR) pre-REBOA SBP in the 11 individuals for whom cannulation was successful (5 [46%] in TCA) was 47 (33-52) mm Hg. Z1 REBOA plus P-REBOA was associated with a significant improvement in BP (median [IQR] SBP at emergency department arrival, 101 [77-107] mm Hg; 0 of 10 patients were in TCA at arrival). The median group-level improvement in SBP from the pre-REBOA value was 52 (95% CI, 42-77) mm Hg (P < .004). P-REBOA was feasible in 8 individuals (8/11 [73%]) and occurred spontaneously in 4 of these. The 1- and 3-hour postinjury mortality rate was 9% (1/11), 24-hour mortality was 27% (3/11), and 30-day mortality was 82% (9/11). Survival to hospital discharge was 18% (2/11). Both survivors underwent early Z1 P-REBOA. Conclusions and Relevance: In this study, prehospital Z1 P-REBOA is feasible and may enable early survival, but with a significant incidence of late death. Trial Registration: ClinicalTrials.gov Identifier: NCT04145271.
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BACKGROUND: Junctional vascular trauma such as that at the thoracic outlet poses particular challenges in surgical management. The use of endovascular techniques for such injuries is attractive as repair may be facilitated without the need for thoracotomy; however, the utility of such techniques is currently based on opinion, small retrospective series, and literature reviews of narrative and not systematic quality. The objective of this study is to provide a complete and systematic analysis of the literature pertaining to open surgery (OS) and endovascular management (EM) of thoracic outlet vascular injuries. METHODS: An electronic search using the MEDLINE, Embase, Cochrane Library, Science Citation Index, and LILACS databases was performed for articles published from 1947 to November 2011. The review conformed to the Preferred Reporting Items for Systematic Reviews and Meta-analyses statement standards. Prospective studies and retrospective cohorts of more than 10 patients were included. The primary outcome was all-cause mortality. RESULTS: One prospective noncomparative study and 73 retrospective series met the inclusion criteria. There were no randomized studies. All studies were at high risk of bias. Fifteen studies described outcomes for both OS and EM (549 patients). The majority of these studies described EM for traumatic arteriovenous fistulas or false aneurysms in stable patients. Direct comparison between OS and EM was possible in only three studies (comprising 23 OS and 25 EM patients), which showed no difference in all-cause mortality (odds ratio, 0.67; 95% confidence interval [CI], 0.11-4.05), but a shorter operating time with EM (mean difference = 58.34 minutes; 95% CI, 17.82-98.85). These three series included successful EM of unstable patients and those with vessel transection. There were 55 studies describing only OS (2057 patients) with a pooled mortality rate of 12.4% (95% CI, 9.9%-15.2%). Four studies described only EM (101 patients) with a pooled mortality rate of 26% (95% CI, 8%-51%), but these represented a distinct subgroup of cases (mainly iatrogenic injuries in older patients). CONCLUSIONS: The current evidence is weak and fails to show superiority of one modality over the other. EM is currently used primarily in highly selected cases, but there are reports of a broader applicability in trauma. High-quality randomized studies or large-scale registry data are needed to further comment on the relative merits or disadvantages of EM in comparison to OS.
Assuntos
Falso Aneurisma/terapia , Fístula Arteriovenosa/terapia , Procedimentos Endovasculares , Extremidade Superior/irrigação sanguínea , Procedimentos Cirúrgicos Vasculares , Lesões do Sistema Vascular/terapia , Adulto , Falso Aneurisma/etiologia , Falso Aneurisma/mortalidade , Falso Aneurisma/cirurgia , Fístula Arteriovenosa/etiologia , Fístula Arteriovenosa/mortalidade , Fístula Arteriovenosa/cirurgia , Causas de Morte , Distribuição de Qui-Quadrado , Procedimentos Endovasculares/efeitos adversos , Procedimentos Endovasculares/mortalidade , Feminino , Humanos , Doença Iatrogênica , Masculino , Razão de Chances , Seleção de Pacientes , Medição de Risco , Fatores de Risco , Resultado do Tratamento , Procedimentos Cirúrgicos Vasculares/efeitos adversos , Procedimentos Cirúrgicos Vasculares/mortalidade , Lesões do Sistema Vascular/etiologia , Lesões do Sistema Vascular/mortalidade , Lesões do Sistema Vascular/cirurgiaRESUMO
INTRODUCTION: Pedal cycling in cities has the potential to deliver significant health and economic benefits for individuals and society. Safety is the main concern for potential cyclists although the statistical risk of death is low. Little is known about the severity of injuries sustained by city cyclists and their outcome. AIM: The aim of this study was to characterise the physiological status and injury profile of cyclists admitted to our urban major trauma centre (MTC). METHODS: Database analysis of cyclist casualties between 2004 and 2009. The physiological parameters examined were admission systolic blood pressure (SBP), admission base deficit and prehospital Glasgow Coma Scale. RESULTS: 265 cyclists required full trauma-team activation. 82% were injured during a collision with a motorised vehicle. The majority (73%) had collided with a car or a heavy goods vehicle (HGV). These casualties formed the cohort for further analysis. Cyclists who collided with an HGV were more severely injured and had a higher mortality rate. Low SBP and high base deficit indicate that haemorrhagic shock is a key feature of HGV casualties. CONCLUSION: Collision with any vehicle can result in death or serious injury to a cyclist. Injury patterns vary with the type of vehicle involved. HGVs were associated with severe injuries and death as a result of uncontrollable haemorrhage. Awareness of this injury profile may aid prehospital management and expedite transfer to MTC care. Rapid haemorrhage control may salvage some, but not all, of these casualties. The need for continued collision prevention strategies and long-term outcome data collection in trauma patients is highlighted.
Assuntos
Acidentes de Trânsito , Ciclismo , Ferimentos e Lesões/epidemiologia , Adulto , Pressão Sanguínea/fisiologia , Feminino , Humanos , Escala de Gravidade do Ferimento , Londres/epidemiologia , Masculino , Pessoa de Meia-Idade , População Urbana , Ferimentos e Lesões/etiologia , Ferimentos e Lesões/fisiopatologiaRESUMO
Objective: The aim of this study was to determine the methods and metrics used to evaluate the usability of mobile application Clinical Decision Support Systems (CDSSs) used in healthcare emergencies. Secondary aims were to describe the characteristics and usability of evaluated CDSSs. Materials and Methods: A systematic literature review was conducted using Pubmed/Medline, Embase, Scopus, and IEEE Xplore databases. Quantitative data were descriptively analyzed, and qualitative data were described and synthesized using inductive thematic analysis. Results: Twenty-three studies were included in the analysis. The usability metrics most frequently evaluated were efficiency and usefulness, followed by user errors, satisfaction, learnability, effectiveness, and memorability. Methods used to assess usability included questionnaires in 20 (87%) studies, user trials in 17 (74%), interviews in 6 (26%), and heuristic evaluations in 3 (13%). Most CDSS inputs consisted of manual input (18, 78%) rather than automatic input (2, 9%). Most CDSS outputs comprised a recommendation (18, 78%), with a minority advising a specific treatment (6, 26%), or a score, risk level or likelihood of diagnosis (6, 26%). Interviews and heuristic evaluations identified more usability-related barriers and facilitators to adoption than did questionnaires and user testing studies. Discussion: A wide range of metrics and methods are used to evaluate the usability of mobile CDSS in medical emergencies. Input of information into CDSS was predominantly manual, impeding usability. Studies employing both qualitative and quantitative methods to evaluate usability yielded more thorough results. Conclusion: When planning CDSS projects, developers should consider multiple methods to comprehensively evaluate usability.