. 2019 Mar 21;7:2050312119835043. doi: 10.1177/2050312119835043

Table 1.

Definitions of sepsis.

Sepsis 1 (1991)⁶
Systemic inflammatory response syndrome (SIRS): systemic inflammatory response to a variety of severe clinical insults:
Temperature >38°C or <36°C; heart rate > 90 beats per min; respiratory rate > 20 breaths per min or PaCO₂ < 32 mmHg; and white blood cell count > 12,000/cu mm, <4000/cu mm, or >10% immature (band) forms
Sepsis is a systemic response to infection, manifested by two or more of the SIRS criteria as a result of infection.
Severe sepsis: Sepsis associated with organ dysfunction, hypoperfusion, or hypotension; hypoperfusion and perfusion abnormalities may include, but not limited to, lactic acidosis, oliguria, or an acute alteration in mental status

Septic shock: Sepsis-induced, with hypotension despite adequate fluid resuscitation along with the presence of perfusion abnormalities that may include, but not limited to, lactic acidosis, oliguria, or an acute alteration in mental status; patients who are receiving inotropic or vasopressor agents may not be hypotensive at the time that perfusion abnormalities are measured.

Sepsis 2 (2001)⁷
Infection: Documented or suspected and some of the following:
General parameters:
Fever (core temperature > 38.3°C); hypothermia (core temperature < 36°C); heart rate > 90 beats per min or > 2 SD above the normal value for age; tachypnea: respiratory rate > 30 breaths per min; altered mental status; significant edema or positive fluid balance (>20 mL kg⁻¹ over 24 h)
Hyperglycemia (plasma glucose > 110 mg dL⁻¹ or 7.7 mM L⁻¹) in the absence of diabetes
Inflammatory parameters:
Leukocytosis (white blood cell count > 12,000/μL); leukopenia (white blood cell count < 4000/μL); normal white blood cell count with > 10% immature forms; plasma C-reactive protein > 2 SD above the normal value; and plasma procalcitonin > 2 SD above the normal value
Hemodynamic parameters:
Arterial hypotension (systolic blood pressure < 90 mmHg, MAP < 70 mmHg, or a systolic blood pressure decrease > 40 mmHg in adults or < 2 SD below normal for age, mixed venous oxygen saturation > 70%, cardiac index > 3.5 L min⁻¹ m⁻²)
Organ dysfunction parameters:
Arterial hypoxemia (PaO₂/FIO₂ < 300); acute oliguria (urine output < 0.5 mL kg⁻¹ h⁻¹ or 45 mM L⁻¹ for at least 2 h); creatinine increase ⩾ 0.5 mg dL⁻¹; coagulation abnormalities (international normalized ratio > 1.5 or activated partial thromboplastin time > 60 s);
ileus (absent bowel sounds);
thrombocytopenia (platelet count < 100,000 μL⁻¹) Hyperbilirubinemia (plasma total bilirubin > 4 mg dL⁻¹ or 70 mmol L⁻¹)

Tissue perfusion parameters:
Hyperlactatemia (>3 mmol L⁻¹); decreased capillary refill or mottling

Sepsis 3 (2016)⁸
Sepsis is a life-threatening organ dysfunction caused by dysregulated host response to infection.

Clinical criteria for sepsis:
Suspected or documented infection and an acute increase of ⩾2 SOFA points (Table 2)

The task force considered that positive qSOFA (quick SOFA) criteria should also prompt consideration of possible infection in patients not previously recognized as infected.

qSOFA criteria:
Altered mental status (GCS score < 15);
systolic blood pressure < 100 mmHg;
respiratory rate > 22 breaths per min
Septic shock is defined as a subset of sepsis in which underlying circulatory and cellular metabolism abnormalities are profound enough to substantially increase mortality.

Septic shock can be identified with a clinical construct of sepsis with persisting hypotension, requiring vasopressor therapy to elevate MAP ⩾ 65 mm
Hg and lactate > 2 mmol L⁻¹ (18 mg dL⁻¹) despite adequate fluid resuscitation

FIO₂: fraction of inspired oxygen; GCS: Glasgow Coma Scale; MAP: mean arterial pressure; PaCO₂: partial pressure of carbon dioxide; PaO₂: partial pressure of oxygen; SOFA: sequential organ failure assessment.