Sepsis represents a life-threatening organ dysfunction caused by a dysregulated host response to infection. The pathophysiological cascade begins when pathogen components (lipopolysaccharide from gram-negative bacteria, lipoteichoic acid from gram-positive bacteria) bind pattern recognition receptors (toll-like receptors) on innate immune cells, triggering massive release of pro-inflammatory cytokines (TNF-alpha, IL-1-beta, IL-6) and activation of complement and coagulation cascades. This inflammatory storm causes widespread endothelial activation and dysfunction, leading to increased vascular permeability (capillary leak), vasodilation (distributive shock), microvascular thrombosis (disseminated intravascular coagulation), and impaired cellular oxygen utilization. Tissue hypoperfusion drives anaerobic metabolism, producing lactic acid -- serum lactate greater than 18.0 mg/dL serves as a critical biomarker of inadequate perfusion. The nurse implements the sepsis bundle (obtain blood cultures before antibiotics, administer broad-spectrum antibiotics within one hour, initiate 30 mL/kg crystalloid for hypotension or lactate greater than or equal to 36.0 mg/dL), monitors for progression to septic shock (vasopressor requirement to maintain MAP greater than or equal to 65 mmHg despite adequate fluid resuscitation), and performs serial reassessment of perfusion markers including lactate clearance, urine output, capillary refill, and mental status.