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

OBJECTIVE: To test the sepsis marker procalcitonin (PCT) for its applicability to discriminate between septic and nonseptic causes of acute respiratory distress syndrome (ARDS). DESIGN: 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. SETTING: Twenty-four-bed medical intensive care unit of a 1,990-bed primary hospital, providing health care for an estimated 39,000 patients. 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. INTERVENTIONS: 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. MEASUREMENTS AND MAIN RESULTS: 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. CONCLUSION: PCT determination in early ARDS could help to discriminate between septic and nonseptic underlying disease.