PULMONARY ENDOTHELIAL PERMEABILITY IN PATIENTS WITH SEVERE LUNG INJURY - CLINICAL CORRELATES AND NATURAL-HISTORY

Study objective: To establish the natural history of lung injury in ad ult respiratory distress syndrome (ARDS) in terms of increased pulmona ry vascular permeability. Secondly, to relate such changes to the numb er of neutrophils in bronchoalveolar lavage (BAL) and a clinical score of the severity of lung injury.Design: Prospective, open. Setting: Ad ult intensive care unit of a tertiary (national) referral hospital.Pat ients: Fourteen patients meeting accepted diagnostic criteria for ARDS . Interventions: Mechanical ventilatory support. Conventional intensiv e care and support for other failed organ systems as appropriate. Meas urements and results: Pulmonary vascular permeability was estimated us ing a dual isotope technique (protein accumulation index [PAI]), neutr ophil numbers by BAL and the severity of ARDS by the lung injury score (LIS). The PAI and LIS were measured simultaneously on three occasion s as far apart as possible during the course of the illness. A single BAL was performed immediately after one of the three PAI/LIS measureme nts, the precise timing being dictated by the clinical stability of ea ch patient. Fourteen patients (8 male; age range, 19 to 69 years) were studied, 1.40 +/- 0.16, 11.36 +/- 1.79, and 20.90 +/- 2.30 days after the onset of ARDS (mean +/- EM). Six patients died. The PAI (normal r ange, 0 to 1.0x10(-3)) was 2.81 +/- 0.39, 2.94 +/- 0.48, and 2.80 +/- 0.87; and LIS (severe injury >2.5) was 2.18 +/- 0.25, 2.48 +/- 0.14, a nd 2.06 +/- 0.27, respectively. The BAL neutrophil content was 54.09 /- 8.89. There were significant positive correlations between PAI and LIS (r=0.73, p<0.001) and PAI and BAL neutrophil content (r=0.81, p<0. 001). Conclusions: These data suggest that increased pulmonary vascula r permeability persists throughout the course of ARDS and is related t o a clinical score of injury severity and BAL neutrophil content.