Discrimination of infectious and noninfectious causes of early acute respiratory distress syndrome by procalcitonin

To test the sepsis marker procalcitonin (PCT) for its applicability to discriminate between septic and nonseptic causes of acute respiratory distress syndrome (ARDS).Prospective study, assessing the course of PCT serum levels in early (within 72 hrs after onset) ARDS. The three other inflammation markers neopterin, interleukin-6 (IL-6), and C-reactive protein (CRP) were tested in parallel.Twenty-four-bed medical intensive care unit of a 1,990-bed primary hospital, providing health care for an estimated 39,000 patients.Twenty-seven patients, 18 male and nine female, aged 16-85 yrs, with early ARDS of known cause (17 with septic and ten with nonseptic ARDS) were enrolled in a prospective study between May 1994 and May 1995.Serum samples were drawn every 4-6 hrs for measurement of PCT, neopterin, IL-6, and CRP concentrations. Blood cultures, tracheal aspirates, and urine samples were obtained every 12-24 hrs. In 24 of 27 patients, bronchoscopic cultures were also obtained. Clinical sepsis criteria as defined by the American College of Chest Physicians/Society of Critical Care Medicine Consensus Conference were checked daily.Assessment of inflammation marker serum levels in septic vs. nonseptic ARDS. PCT serum levels were significantly higher (p.0005) in the patients with septic ARDS than in patients with nonseptic ARDS within 72 hrs after onset of ARDS. There was no overlap between the two groups. Also, neopterin allowed a differentiation (p.005), although a substantial overlap between serum levels of septic and nonseptic patients was observed. No discrimination could be achieved by determination of CRP and IL-6 levels.PCT determination in early ARDS could help to discriminate between septic and nonseptic underlying disease.