IMG-ED AIRWAY FELIX 2.0: A Multilevel Dysoxia Model and Threshold-Based Clinical Decision System for Airway Management in Inhalation Injury

Overview Inhalation injury remains a major determinant of morbidity and mortality in burn patients, particularly in confined-space smoke exposure. Current clinical approaches (ABLS, ISBI) rely predominantly on qualitative criteria that often identify airway compromise at late stages. This work introduces the IMG-ED AIRWAY FELIX 2.0 model, a physiologically grounded conceptual framework that reconceptualizes inhalation injury as a multilevel oxygen failure system, involving: Impaired alveolar diffusion Disrupted oxygen transport (carboxyhemoglobinemia) Inhibition of mitochondrial oxygen utilization (cytochrome c oxidase – Complex IV) The model proposes the concept of “mitochondrial asphyxia” as a central mechanism linking early toxic exposure (carbon monoxide and cyanide) to cellular dysoxia, lactate elevation, and subsequent clinical deterioration. FELIX Index A clinical scoring system (0–14 points) is introduced, integrating eight variables across three domains: Diffusion (airway/respiratory signs) Exposure (time and combustion material) Cellular utilization (lactate, pH, COHb) This index enables early risk stratification, identification of physiological thresholds, and structured decision-making for: Airway management (timing of intubation) Antidote administration (hydroxocobalamin) Hyperbaric oxygen therapy Key Contribution Unlike traditional models focused on mortality prediction, the IMG-ED AIRWAY FELIX model is designed for real-time clinical decision-making, aiming to detect deterioration before the onset of overt airway obstruction or neurological compromise. Scientific Positioning This manuscript represents a hypothesis-driven, physiologically coherent conceptual model. It does not provide deterministic prediction, but rather a probabilistic framework intended to support clinical judgment and guide future validation studies. Clinical Relevance The integration of early clinical signals (voice changes) with biochemical markers (lactate) offers a practical and scalable approach for emergency, prehospital, and critical care settings, particularly in resource-limited environments. Keywords Inhalation injury; airway management; mitochondrial dysfunction; carbon monoxide poisoning; cyanide poisoning; lactate; critical care; burn injury; dysoxia; hydroxocobalamin