The nurse manages delirium through prevention protocols, early detection, cause identification, and evidence-based intervention, while simultaneously managing chronic dementia care needs. The ABCDEF ICU bundle incorporates delirium prevention: A (Assess, prevent, manage pain), B (Both spontaneous awakening and breathing trials), C (Choice of sedation -- target light sedation, avoid benzodiazepines), D (Delirium assessment and management using CAM-ICU), E (Early mobility and exercise), F (Family engagement and empowerment). Delirium pathophysiology involves multiple converging mechanisms: (1) Cholinergic deficiency (anticholinergic medications, acute illness reducing ACh synthesis), (2) Dopaminergic excess (explaining antipsychotic efficacy for symptoms), (3) Neuroinflammation (systemic inflammation from infection/surgery triggers microglial activation, cytokine production, and BBB disruption), (4) Oxidative stress (ischemia, metabolic derangement), (5) Circadian rhythm disruption (ICU environment, medication timing, sleep deprivation). Delirium has significant prognostic implications: associated with 2-3x increased mortality, longer hospital stay, higher risk of falls, higher rate of post-discharge institutionalization, and ACCELERATED cognitive decline (delirium may cause permanent brain injury -- not always fully reversible as previously thought). For dementia, the nurse implements person-centered care (Kitwood model): recognizing the person behind the disease, maintaining dignity, supporting remaining...