RESUMO
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.
Assuntos
Cuidados Críticos/estatística & dados numéricos , Estudos Epidemiológicos , Pesquisa/estatística & dados numéricos , Algoritmos , Estudos de Casos e Controles , Causalidade , Ensaios Clínicos como Assunto/ética , Ensaios Clínicos como Assunto/estatística & dados numéricos , Grupos Controle , Projetos de Pesquisa Epidemiológica , Ética em Pesquisa , Humanos , Incidência , Estudos Observacionais como Assunto/ética , Estudos Observacionais como Assunto/estatística & dados numéricos , Projetos de Pesquisa , Medição de Risco , Estatísticas não ParamétricasAssuntos
Isquemia Encefálica/tratamento farmacológico , Fibrinolíticos/efeitos adversos , Hemoptise/induzido quimicamente , Acidente Vascular Cerebral/tratamento farmacológico , Terapia Trombolítica/efeitos adversos , Ativador de Plasminogênio Tecidual/efeitos adversos , Doença Aguda , Idoso , Isquemia Encefálica/complicações , Evolução Fatal , Humanos , Masculino , Acidente Vascular Cerebral/etiologiaRESUMO
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