Intra-alveolar urinary trypsin inhibitor cannot inhibit polymorphonuclear elastase activity in the lung in postsurgical patients with acute respiratory distress syndrome

The aim of this study was to evaluate the concentrative relationship betwee n polymorphonuclear elastase (PMNE) and urinary trypsin inhibitor (UTI) in the bronchoalveolar lavage fluid (BALF) of patients with acute respiratory distress syndrome (ARDS). A total of eight patients who developed ARDS afte r gastroenterological surgery and eight patients with normal respiratory fu nction during general anesthesia using tracheal intubation were the subject s of this study. BALF was collected from the right middle lobe using saline , and the PMNE and UTI concentrations were measured. The PMNE concentration s were 1277 +/- 1589 ng/ml and 38 +/- 26 ng/ml in the patients with ARDS an d those with normal lung function, respectively, and the UTI concentrations were 225 +/- 175 mU/ml and 81 +/- 40 mU/ml, respectively, expressed as mea n +/- SD. Based on the UTI concentration which can inhibit PMNE activity, t he PMNE concentration in the ARDS patients was not entirely inhibited by UT I. Since only UTI can inhibit PMNE activity in the inflammatory tissues, PM NE in the BALF may induce and aggravate lung injury in ARDS. Thus, we concl ude that PMNE released from activated neutrophils in the lung is associated with the development of ARDS.