Shock is a life-threatening syndrome of acute circulatory failure resulting in inadequate oxygen delivery (DO₂) to meet cellular metabolic demands — the fundamental equation being DO₂ = CO × CaO₂ (cardiac output × arterial oxygen content). Cellular hypoxia drives anaerobic metabolism, lactic acid accumulation, and organ failure. Untreated shock progresses irreversibly within minutes to hours: 90-day mortality from septic shock exceeds 40%. Four pathophysiologically distinct shock types share a common endpoint — cellular death — but require fundamentally different resuscitation strategies. Misclassifying cardiogenic shock as hypovolaemic and administering 30 mL/kg IV fluids will precipitate pulmonary oedema and acute respiratory failure. Top 3 Nursing Priorities: 1. Recognize shock early using MAP, lactate, and mental status before BP crashes — compensated shock is treatable; decompensated shock kills 2. Identify shock TYPE immediately — treatment diverges sharply (fluids vs. vasopressors vs. needle decompression vs. epinephrine) 3. Establish IV access × 2 large bore, initiate continuous monitoring, obtain stat labs and cultures — do not delay treatment for diagnostics NCLEX Trap: Neurogenic shock presents with hypotension + bradycardia (not tachycardia) + warm, dry skin...