Table 1. Sepsis and Septic Shock Clinical Criteria Over Time.

Consensus	Clinical criteria
Sepsis-1, 1991 [13]	Sepsis: Systemic response to an infection, manifested by two or more of the following components of the systemic inflammatory response syndrome (SIRS): a) temperature >38°C or <36°C; b) heart rate >90 beats per minute; c) respiratory rate >20 breaths per minute or PaCO2 <32mmHg; and d) white cell blood count >12,000 cells per mL, <4,000 cells per mL, or >10% immature forms.
	Severe sepsis:
	Sepsis associated with organ dysfunction, hypoperfusion, or hypotension.
	Septic shock:
	Sepsis-induced hypotension (SBP <90 mmHg or an SBP reduction ≥40 mmHg from baseline) despite adequate fluid resuscitation, or requiring vasopressor agents, along with the presence of perfusion abnormalities.
Sepsis-2, 2001 [14]	Sepsis: Documented or suspected infection with some signs of systemic inflammation, which were expanded from the SIRS criteria to include abnormalities from 5 major categories (general variables, inflammatory variables, hemodynamic variables, organ dysfunction variables, and tissue perfusion variables).
	Severe sepsis:
	Sepsis associated with organ dysfunction, which can be estimated with the SOFA score.
	Septic shock:
	Persistent arterial hypotension (SBP <90 mmHg, MAP <60 mmHg, or reduction in SBP >40 mmHg from baseline) despite adequate fluid resuscitation and unexplained by other causes.
Sepsis-3, 2015 [2]	Sepsis: Suspected or documented infection and acute organ dysfunction (defined as an increase of ≥ 2 points in SOFA points).
	Septic shock:
	Sepsis and vasopressor therapy needed to elevate MAP ≥65 mmHg and lactate >2 mmol/L despite adequate fluid resuscitation.

PaCO₂: partial pressure of carbon dioxide; SBP: systolic blood pressure; MAP: mean arterial blood pressure; SOFA: Sequential Organ Failure Assessment.