SIRS criteria and sepsis screening.
SIRS ≥ 2 + suspected infection = sepsis (Sepsis-1 definition). Sepsis-3 uses SOFA ≥ 2 + suspected infection. qSOFA (RR ≥ 22, SBP ≤ 100, altered mentation) screens outside ICU. Septic shock: sepsis + vasopressors needed + lactate > 2 despite fluids. Early recognition and the 1-hour bundle save lives.