Avaliação dos protocolos de morte encefálica

Abstract

The inherent complexity and urgency of diagnosing Brain Death (BD) constitute a persistent challenge in Intensive Care Units (ICU), representing a critical factor for the success of the National Transplant Policy (PNT). BD, defined as the irreversible cessation of all brain functions, is the legal premise of death authorizing organ removal, in accordance with Law No. 9,434/97 and CFM Resolution No. 2,173/17. The ethical and logistical imperative demands absolute celerity and safety, given that delay compromises organ viability. Furthermore, initiating the BD diagnostic protocol entails a fatal prognosis, culminating either in BD confirmation or Cardiac Arrest (PCR). With the objective of optimizing the diagnosis and the rational use of ancillary tests, such as the Electroencephalogram (EEG), this thesis sought to establish a robust predictive score capable of differentiating progression to BD from Death by Cardiac Arrest (PCR) in neurocritical patients. The study was conducted as a retrospective cohort analysis, approved by the Ethics Committee (CEP) of the Universidade Federal de Uberlândia (UFU), utilizing an Analytical Sample of N=66 patients and applying Binary Logistic Regression to identify independent predictive factors. The statistical model confirmed that the outcome is primarily determined by the initial neurovascular severity. Two clinical factors were identified as the most robust predictors for the outcome of Brain Death: the initial Glasgow Coma Scale (GCS) score and the Use of Vasoactive Drugs (DVA). The initial GCS score proved to be the strongest independent predictor (OR = 1.70; p=0.002), indicating that the BD outcome is intrinsically linked to catastrophic initial neurological injury. Complementarily, the use of DVA was a strong predictor of BD (OR = 0.04; p=0.031), as the need for pressure support (observed in approximately 95% of BD cases) is a robust marker of neurogenic shock and brainstem failure, reducing the chance of death by PCR by 96%. Univariate analyses corroborated that Traumatic Brain Injury (TBI) etiology was significantly more prevalent in the BD Group (approximately 44% vs. 0% in the PCR Group; p=0.022), reinforcing the epidemiological profile of high-impact acute lesions. Furthermore, the extremely low rate of Cardiac Arrest in the BD Group (approximately 1.7%; p<0.001) attested to the high quality of intensive clinical management, maintaining organ viability until the legal declaration of death. Regarding ancillary testing, Quantitative EEG (QEEG) analysis in selected cases demonstrated that progression to BD is marked by a profound electrophysiological disorganization, featuring an inversion in power patterns and extreme, dysregulated variability of electrical activity. This reinforces the potential of EEG, due to its non-invasive and cost-effective nature, as an ideal tool within the reality of the public health system (SUS). The main practical contribution of this thesis resides in the proposition of the Predictive Triage Model (GCS + DVA). This model allows for the quicker and more focused activation of the BD protocol and complementary examinations, particularly concentrating on EEG use. This optimization directly contributes to maintaining organ viability. In summary, the work demonstrates that the integration of methodological rigor from data science with clinical physiology establishes powerful tools to refine the diagnosis of Brain Death, ensuring the excellence and efficiency demanded by the ethical and legal imperative