Evaluating apnea test protocols for brain death diagnosis in adults: methods, safety, and ethical considerations

Brain death determination is a critical process in modern medicine, particularly in the context of organ donation. The apnea test (AT) constitutes a fundamental component of this determination by confirming the irreversible cessation of brainstem-mediated respiratory function. Despite its clinical importance, AT protocols vary widely across regions, resulting in significant differences in safety, effectiveness, and ethical considerations. This review presents a comprehensive analysis of existing AT protocols, comparing traditional and modified methodologies designed to improve diagnostic accuracy while minimizing complications. It examines innovative approaches, including CO₂ delivery techniques, continuous positive airway pressure-assisted methods, and protocol adaptations for patients supported with extracorporeal membrane oxygenation. In addition, this article evaluates potential AT-related risks, such as hemodynamic instability, hypoxemia, and barotrauma, while emphasizing the ongoing need for standardized international protocols. Furthermore, the ethical and legal dimensions of AT, particularly the ongoing debate regarding informed consent, are critically examined. Given the inherent risks of AT and the availability of ancillary diagnostic alternatives, the necessity of AT in brain death determination remains contested. This review therefore underscores the urgent need for consensus-driven guidelines that prioritize patient safety, uphold ethical standards, and preserve the integrity of organ donation practices.