Objective: To compare the evolution of plasma concentrations of leukotriene (LT) B4, LTC4, LTD4, and interleukin (IL)-8 in patients with acute respiratory distress syndrome (ARDS) and in patients at risk of ARDS and to assess the value of these mediators in predicting mortality rate from ARDS.
Design: A case-control study comparing ARDS patients and patients at risk of ARDS as well as survivors and nonsurvivors with ARDS.
Setting: Hospital intensive care unit, laboratory, and department of hematology.
Patients: Twenty-one patients with ARDS and 14 patients at risk of ARDS.
Intervention: Arterial blood samples were collected on days 0, 1, and 5 after admission to the intensive care unit.
Measurements and main results: LTs were extracted, separated by high-pressure liquid chromatography and quantified by enzyme immunoassay. IL-8 was analyzed by ELISA. Plasma concentrations of LTB4 and LTC4 plus LTD4 were significantly higher in ARDS patients than in patients at risk of ARDS during the first 24 hrs. Concentrations of IL-8 were also higher in ARDS patients than in patients at risk throughout the study, although the differences between the two groups were only significant on day 5. Only the plasma concentration of LTB4 on day 1 was a marker of ARDS (72.2% sensitivity, 84.6% specificity). A logistic regression analysis showed that LTB4 and IL-8, on day 1, were markers of mortality rate in patients with ARDS (70.0% sensitivity, 87.5% specificity).
Conclusions: LTs are elevated during the early phases of ARDS, whereas IL-8 increases throughout the study. The evaluation of LTB4 and IL-8 may be useful prognostic indices in patients with early phase ARDS after admission to the intensive care unit.