Abstract Arterial hypertension is responsible for high morbidity and mortality. Despite increasing awareness of the consequences of uncontrolled hypertension and the publication of several recommendations and guidelines, blood pressure control rates are suboptimal, and approximately half of the patients do not reach the targets. Defined as an increase in blood pressure, hypertension is characterized by hemodynamic abnormalities in cardiac output, systemic vascular resistance, or arterial compliance. Therefore, the approach to arterial hypertension can be improved by the knowledge of the hemodynamics underlying the blood pressure increase. Impedance Cardiography has emerged as a new strategy to customize therapy and monitor patients aiming to improve blood pressure control according to the hemodynamic profile, rather than a blind intensive care approach. This is a review of impedance cardiography evidence, its benefits, actual and future applications in the approach and management of arterial hypertension.

Resumo Objetivo: A determinação do prognóstico de pacientes em coma após parada cardíaca tem implicações clínicas, éticas e sociais. Exame neurológico, marcadores de imagem e bioquímicos são ferramentas úteis e bem aceitas na previsão da recuperação. Com o advento da hipotermia terapêutica, tais informações devem de ser confirmadas. Neste estudo procurou-se determinar a validade de diferentes marcadores que podem ser utilizados na detecção de pacientes com mau prognóstico durante um protocolo de hipotermia. Métodos: Foram coletados prospectivamente os dados de pacientes adultos, internados após parada cardíaca em nossa unidade de terapia intensiva para realização de protocolo de hipotermia. Nosso intuito foi realizar um estudo descritivo e analítico para analisar a relação entre os dados clínicos, parâmetros neurofisiológicos, de imagem e bioquímicos, e o desfecho após 6 meses, conforme definido pela escala Cerebral Performance Categories (bom, se 1-2, e mau, se 3-5). Foi coletada uma amostra para determinação de neuroenolase após 72 horas. Os exames de imagem e neurofisiológicos foram realizados 24 horas após o período de reaquecimento. Resultados: Foram incluídos 67 pacientes, dos quais 12 tiveram evolução neurológica favorável. Fibrilação ventricular e atividade teta no eletroencefalograma se associaram a bom prognóstico. Pacientes submetidos a resfriamento mais rápido (tempo médio de 163 versus 312 minutos), com lesão cerebral causada por hipóxia/isquemia detectada na ressonância nuclear magnética ou níveis de neuroenolase superiores a 58ng/mL se associaram a desfecho neurológico desfavorável (p < 0,05). Conclusão: A presença de lesão cerebral causada por hipóxia/isquemia e de neuroenolase foram fortes preditores de má evolução neurológica. Apesar da crença de que atingir rapidamente a temperatura alvo da hipotermia melhora o prognóstico neurológico, nosso estudo demonstrou que este fator se associou a um aumento da mortalidade e a uma pior evolução neurológica.

ABSTRACT Objective: The determination of coma patient prognosis after cardiac arrest has clinical, ethical and social implications. Neurological examination, imaging and biochemical markers are helpful tools accepted as reliable in predicting recovery. With the advent of therapeutic hypothermia, these data need to be reconfirmed. In this study, we attempted to determine the validity of different markers, which can be used in the detection of patients with poor prognosis under hypothermia. Methods: Data from adult patients admitted to our intensive care unit for a hypothermia protocol after cardiac arrest were recorded prospectively to generate a descriptive and analytical study analyzing the relationship between clinical, neurophysiological, imaging and biochemical parameters with 6-month outcomes defined according to the Cerebral Performance Categories scale (good 1-2, poor 3-5). Neuron-specific enolase was collected at 72 hours. Imaging and neurophysiologic exams were carried out in the 24 hours after the rewarming period. Results: Sixty-seven patients were included in the study, of which 12 had good neurological outcomes. Ventricular fibrillation and electroencephalographic theta activity were associated with increased likelihood of survival and improved neurological outcomes. Patients who had more rapid cooling (mean time of 163 versus 312 minutes), hypoxic-ischemic brain injury on magnetic resonance imaging or neuron-specific enolase > 58ng/mL had poor neurological outcomes (p < 0.05). Conclusion: Hypoxic-ischemic brain injury on magnetic resonance imaging and neuron-specific enolase were strong predictors of poor neurological outcomes. Although there is the belief that early achievement of target temperature improves neurological prognoses, in our study, there were increased mortality and worse neurological outcomes with earlier target-temperature achievement.