Phenomenology of a Biographical Disruption: Delirium in the Critically Ill Patient.

RATIONALE: Delirium in the Intensive Care Unit (ICU) is an acute neurocognitive syndrome affecting up to 80% of patients on mechanical ventilation. While traditionally defined by biomedical criteria (DSM-5), these metrics often overlook the profound ontological rupture and subjective alienation experienced by the patient. AIMS AND OBJECTIVES: This study aims to integrate clinical evidence with phenomenological reflection to evaluate how delirium alters patient identity and to define the resulting ethical responsibilities for the clinical team. METHOD: An interdisciplinary conceptual analysis was conducted, merging pathophysiological data and clinical meta-analyses with philosophical frameworks, including the phenomenology of perception, narrative identity and the ethics of vulnerability. RESULTS: Delirium suspends the 'intentional arc', leading to a collapse of the lived world, fragmented temporality and distorted otherness. Subphenotypes like hypoactive delirium often result in 'epistemic injustice' by silencing the patient's subjective testimony. Post-Intensive Care Syndrome (PICS) is identified as a 'biographical disruption' and a wound to selfhood. CONCLUSION: Clinical evaluation must transcend pathophysiology to include 'narrative competence', enabling the reconstruction of the patient's fractured history. Bioethics should shift from abstract rational autonomy toward a model of 'relational autonomy' grounded in vulnerability.