Systemic inflammatory response and progression to severe sepsis in critically ill infected patients

The systemic inflammatory response syndrome has low specificity to identify infected patients at risk of worsening to severe sepsis or shock.

To examine the incidence of and risk factors for worsening sepsis in infected patients.

A 1-year inception cohort study in 28 intensive care units of patients (n = 1,531) having a first episode of infection on admission or during the stay.

The cumulative incidence of progression to severe sepsis or shock was 20% and 24% at Days 10 and 30, respectively. Variables independently associated (hazard ratio [HR]) with worsening sepsis included: temperature higher than 38.2 degrees C (1.6), heart rate greater than 120/minute (1.3), systolic blood pressure higher than 110 mm Hg (1.5), platelets higher than 150 x 109/L (1.5), serum sodium higher than 145 mmol/L (1.5), bilirubin higher than 30 mumol/L (1.3), mechanical ventilation (1.5), and five variables characterizing infection (pneumonia [HR 1.5], peritonitis [1.5], primary bacteremia [1.8], and infection with gram-positive cocci [1.3] or aerobic gram-negative bacilli [1.4]). The 12 weighted variables were included in a score (Risk of Infection to Severe Sepsis and Shock Score, range 0-49), summarized in four classes of "low" (score 0-8) and "moderate" (8.5-16) risk (9% and 17% probability of worsening, respectively), and of "high" (16.5-24) and "very high" (score > 24) risk (31% and 55% probability, respectively).

One of four patients presenting with infection/sepsis worsen to severe sepsis or shock. A score estimating this risk, using objectively defined criteria for systemic inflammatory response syndrome, could be used by physicians to stratify patients for clinical management and to test new interventions.