Bispectral Index monitoring as an early neurological prognostic tool after an out-of-hospital cardiac arrest successfully resuscitated: a prospective cohort study

Abstract

Introduction: out-of-hospital cardiac arrests are one of the major complications of cardiovascular diseases. Patients who survive a cardiac arrest suffer what is known as Post-Cardiac Arrest Syndrome, which worst consequence is the post-anoxic encephalopathy, the leading cause of disability in patients after cardiac arrest. Therapeutic hypothermia, among other interventions, has proven to diminish the damage to the brain when the patient is in this situation. But, in order to avoid the painful sensation this treatment causes, patients are sedated. This makes the neurological evaluation of the patients unreliable with the tools we have until now. So, we have to wait more than 72 hours to have an accurate prognostic of the patient. In such situation, where therapeutic decisions on highly invasive acute cardiac assistance have to be taken, the actual lapse of time is unacceptable. In the last years, researchers have been looking for new tools that make possible to give an earlier and accurate prognosis among patients who have suffered cardiac arrests successfully resuscitated undergoing therapeutic hypothermia. Bispectral index monitoring has been proposed as a proper tool to assess the neurological prognostic since it could provide us information about the cerebral perfusion probably earlier than the available tools. Objective: the aim of this study is to describe patterns among the graphs created with Bispectral Index values of each patient and to identify if these patterns have a prognostic value in terms of neurological and functional outcomes at discharge from hospital and at follow up at 6 months and at the first year. We want to find as well a cut-off point, which in the first 24 hours allow clinicians to classify patients who had suffered a cardiac arrest successfully resuscitated according to their neurological outcomes. Design: it will be a multi-centric prospective cohort study involving the coronary care units of Hospital Universitari Josep Trueta (Girona), Hospital Universitari de la Vall d’Hebron (Barcelona), Hospital Universitari de la Santa Creu i Sant Pau (Barcelona), Hospital Universitari de Bellvitge (Hospitalet del Llobregat) and Hospital Universitari Germans Trias i Pujol (Badalona). Methods: 330 adult patients who have suffered an out-of-hospital cardiac arrest successfully resuscitated and undergoing therapeutic hypothermia will be included in our study. Since the moment therapeutic hypothermia starts, all of them will be connected to Bispectral index monitors by a sensor-strip located in their foreheads. We will record the first 72 hours of Bispectral index monitoring. This study will be conducted in three years