ABSTRACT
En los estudios de casos y controles anidados, el muestreo de los controles se hace habitualmente por densidad de incidencia y mediante emparejamiento. Con respecto a los casos control clásicos, son más eficientes, permiten el cálculo de la incidencia de la enfermedad y cuentan con más validez interna por la menor presencia de sesgo. Las técnicas de riesgos competitivos pueden usarse si se estudian diferentes tipos de eventos y nos centramos en el tiempo y el tipo del primer evento. El particionamiento recursivo es un tipo de análisis multivariante cuyo propósito es la construcción de algoritmos de clasificación, especialmente útiles cuando hay un gran número de variables predictoras con relaciones complejas con el evento objeto de estudio
In nested case-control studies, sampling of controls is usually done by density of incidence and pairing. With regard to the classic control cases studies, nested ones are more efficient, allow the calculation of the incidence of the disease and they have more internal validity due to the lower presence of bias. Competitive risks techniques can be used if we study different types of events and focus on the time and type of the first event. Recursive partitioning is a type of multivariate analysis whose purpose is the construction of classification algorithms, and it is especially useful when there are a large number of predictive variables with complex relationships with the event
Subject(s)
Humans , Case-Control Studies , Clinical Trials as Topic/ethics , Critical Care/statistics & numerical data , Epidemiologic Studies , Research/statistics & numerical data , Algorithms , Causality , Clinical Trials as Topic/statistics & numerical data , Control Groups , Epidemiologic Research Design , Ethics, Research , Observational Studies as Topic/ethics , Observational Studies as Topic/statistics & numerical dataABSTRACT
In nested case-control studies, sampling of controls is usually done by density of incidence and pairing. With regard to the classic control cases studies, nested ones are more efficient, allow the calculation of the incidence of the disease and they have more internal validity due to the lower presence of bias. Competitive risks techniques can be used if we study different types of events and focus on the time and type of the first event. Recursive partitioning is a type of multivariate analysis whose purpose is the construction of classification algorithms, and it is especially useful when there are a large number of predictive variables with complex relationships with the event.
Subject(s)
Critical Care/statistics & numerical data , Epidemiologic Studies , Research/statistics & numerical data , Algorithms , Case-Control Studies , Causality , Clinical Trials as Topic/ethics , Clinical Trials as Topic/statistics & numerical data , Control Groups , Epidemiologic Research Design , Ethics, Research , Humans , Incidence , Observational Studies as Topic/ethics , Observational Studies as Topic/statistics & numerical data , Research Design , Risk Assessment , Statistics, NonparametricSubject(s)
Brain Ischemia/drug therapy , Fibrinolytic Agents/adverse effects , Hemoptysis/chemically induced , Stroke/drug therapy , Thrombolytic Therapy/adverse effects , Tissue Plasminogen Activator/adverse effects , Acute Disease , Aged , Brain Ischemia/complications , Fatal Outcome , Humans , Male , Stroke/etiologyABSTRACT
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No disponible
Subject(s)
Male , Aged , Humans , Stroke/drug therapy , Thrombolytic Therapy/adverse effects , Hemoptysis/chemically induced , Cerebral Hemorrhage/chemically induced , Radiography, Thoracic , Risk Factors , Multiple Organ FailureABSTRACT
INTRODUCTION: Current Spanish law defines the criteria to be met in the case of brain death (BD) and the complementary tests to confirm it, although they do not always need to be carried out. In Spain one of the most frequently used methods is the electroencephalogram (EEG), which has its shortcomings in patients who are under sedation with barbiturates. Transcranial Doppler (TCD) offers a number of advantages in the diagnosis of BD, but it also has certain limitations. In these cases, a cerebral perfusion scan (CPS) with HMPAO can be very useful. CASE REPORTS: We describe the case of two patients who were admitted to the Intensive Care Unit with serious traumatic brain injuries. Progress was unfavourable and the findings of the clinical exploration were compatible with BD. Since we were dealing with patients under barbiturate therapy, the EEGs were complex and difficult to interpret. TCD was difficult to perform in both cases because of loss of brain matter and displacement of intracranial structures, respectively. CPS, however, allowed us to confirm the diagnosis of BD. CONCLUSION: Although it has obvious advantages, TCD cannot always be performed to confirm BD diagnosis. In these cases, CPS can be an extremely valuable tool
Subject(s)
Brain Death/diagnosis , Oximes , Radiopharmaceuticals , Tomography, X-Ray Computed , Adult , Brain/blood supply , Echoencephalography , Electroencephalography , Humans , Male , Public Health/legislation & jurisprudence , Spain , Ultrasonography, Doppler, TranscranialABSTRACT
Introducción. La legislación española vigente establece los criterios de muerte encefálica (ME) y las pruebas complementarias de confirmación -que no siempre es necesario realizar-.Entre ellas, la más utilizada en nuestro país es el electroencefalograma (EEG), que tiene limitaciones en pacientes con sedación barbitúrica. El Doppler transcraneal (DTC) presenta numerosas ventajas para el diagnóstico de ME, pero también algunas limitaciones. En esos casos, la gammagrafía de perfusión cerebral (GPC) con HMPAO puede ser de gran utilidad. Casos clínicos. Se presentan dos pacientes jóvenes que ingresan en la Unidad de Cuidados Intensivos tras traumatismo craneoencefálico grave. Evolucionan desfavorablemente y presentan exploración clínica compatible con ME. Los EEG, al tratarse ambos pacientes con barbitúricos, son de interpretación compleja. El DTC es difícil de realizar en ambos casos, por presentar pérdida de masa encefálica y desplazamiento de estructuras intracraneales, respectivamente. La GPC, sin embargo, permitió confirmar el diagnóstico de ME. Conclusión. El DTC, aunque presenta evidentes ventajas, no siempre puede realizarse para confirmar el diagnóstico de ME. En esos casos, la GPC puede ser muy útil (AU)
