The influence of volume and intensive care unit organization on hospital mortality in patients admitted with severe sepsis: a retrospective multicentre cohort study

Table 1 Definitions used to select patients with severe sepsis at the ICU

Criteria	Definitions used in the study
SIRS criteria	At least two of the following within the first 24 hours of the ICU stay:
	Core temperature > 38.0°C or < 36.0°C
	Heart rate > 90 beats/min
	Respiratory rate = 20 breaths/minute or PaCO₂ = 32 mmHg or mechanical ventilation
	Leucocyte count < 4,000/mm³ or > 12,000/mm³
Infection	Diagnosis of infection confirmed by laboratory results within first 24 hours of ICU stay^a
Organ	At least one of the following to be present within the first 24 hrs of ICU stay:
dysfunction	Cardiovascular: systolic blood pressure = 90 mmHg or decrease in systolic blood pressure of = 40 mmHg, or use of vasoactive medication to maintain the blood pressure > 90 mmHg for = 1 hour
	Renal: mean urine production < 0.50 ml/kg body weight per hour; if the patient is on chronic renal replacement therapy, then another organ failure dysfunction criterion must be satisfied
	Respiratory: PaO₂/FiO₂ = 300 (or PaO₂/FiO₂ = 200 if admission diagnosis is respiratory infection)
	Haematological: platelet count = 100,000/mm³
	Metabolic: pH = 7.30

^aIn accordance with the definition of 'confirmed infection' used within the NICE registry, a strong suspicion of infection in combination with radiology results (for instance, new infiltrate on thoracic radiograph) and clinical findings (purulent sputum and fever) are also counted as an infection. FiO₂, fractional inspired oxygen; ICU, intensive care unit; NICE, National Intensive Care Evaluation; PaO₂, arterial oxygen tension; SIRS, Systemic Inflammatory Response Syndrome.

ISSN: 1364-8535