Table 1.

Definitions of sepsis

	Criteria/definition
SIRS	Fever or hypothermia (body temperature < 36°C or > 38°C)
	Tachycardia (> 90 beats/min)
	Tachypnoea (> 20 breaths/min or PaCO2 < 4.3 kPa (32 mmHg) during spontaneous breathing or the need for artificial respiration)
	Leucocytes > 12000/mm3 or < 4000/mm3 or > 10% immature neutrophils
Sepsis	Presence of a confirmed or strongly suspected infection and occurrence of at least two SIRS criteria during the first 24 hours of ICU admission
Severe sepsis	Sepsis in combination with the occurrence of at least one failing organ system (defined below) within the first 24 hours of ICU admission
Septic shock	Sepsis in combination with the occurrence of cardiovascular organ failure and metabolic dysfunction (defined below) during the first 24 hours of ICU admission
Acute organ failure	CNS dysfunction: acute deterioration of neurological condition not attributable to start of sedation or CNS disease in the 24 hours before admission or during the period of observation
	Cardiovascular system dysfunction: systolic blood pressure ≤ 90 mmHg or mean arterial pressure ≤ 70 mmHg for 1 hour, despite adequate fluid resuscitation, or the need to administer vasopressors in order to maintain systolic blood pressure ≥ 90 mmHg or mean arterial pressure ≥ 70 mmHg
	Kidney failure: urine output < 0.5 ml/kg per hour for at least 1 hour, despite adequate fluid resuscitation, or serum creatinine ≥ 177 μmol/l not attributable to chronic kidney failure
	Respiratory system dysfunction: a ratio of PaO2 to FiO2 < 26.6 kPa if source of infection was not pulmonary and < 33.2 kPa if infection source was pulmonary, or if mechanical or noninvasive artificial respiration was indicated because of clinical respiratory insufficiency within the first 24 hours of admission
	Haematological dysfunction: platelet count < 80,000/mm3, or a decrease of at least 50% in the 2 days preceding admission
	Metabolic dysfunction: metabolic acidosis (pH ≤ 7.30 or base deficit ≥ 5.0 mmol/l) in association with a plasma lactate level > 3.0 mmol/l
	Liver dysfunction: bilirubin > 43 μmol/l, or ALT (SGPT) > 50 U, or PTT more than 1.5 times normal or INT > 1.5 in the absence of systemic anticoagulant agents

ALT, alanine aminotransferase; PaCO₂, arterial carbon dioxide tension; CNS, central nervous system; FiO₂, fractional inspired oxygen; ICU, intensive care unit; SGPT, serum glutamate-pyruvate transaminase; SIRS, systemic inflammatory response syndrome.