title: Assessment of lung injury in the adult respiratory distress syndrome using multiple indicator dilution curves.
abstract: To assess its usefulness as an index of lung injury in critically ill patients with respiratory failure, the lung microvascular permeability surface area product for urea (14C-PSu) was measured using a multiple radioisotopic indicator dilution technique in 10 patients with the adult respiratory distress syndrome (ARDS) and in a control population of 5 patients without ARDS. The mean values for 14C-PSu and for extravascular lung water (EVLW) were both significantly elevated in patients with ARDS compared with those in control patients (14C-PSu: 18.7 +/- 4.4 versus 7.6 +/- 0.7, p less than 0.05; EVLW: 676 +/- 55 versus 269 +/- 53, p less than 0.001); 14C-PSu and EVLW were significantly correlated (R = 0.52, p less than 0.001). In the patients with ARDS, 14C-PSu and oxygenation, assessed as the alveolar-arterial oxygen difference, did not appear to be correlated. Repeated measurements of 14C-PSu were variable in the 3 control patients in whom 4 or more measurements were obtained (SD = 50, 57, and 54% of the mean values, respectively); 14C-PSu did not predict clinical outcome assessed by survival of individual patients with ARDS. These data suggest that measurement of 14C-PSu in critically ill patients is a clinically applicable parameter that reflects the degree of microvascular injury in groups of patients. However, our study did not indicate a clear advantage of 14C-PSu over EVLW in assessing lung injury in this patient population. The variability in 14C-PSu control patients also suggests that directional changes in 14C-PSu, as a measure of changes in the degree of lung microvascular dysfunction, should be interpreted with caution.
mesh_terms: D000328:Adult; D000368:Aged; D001834:Body Water / Q000378:metabolism; D002250:Carbon Radioisotopes; D005260:Female; D006439:Hemodynamics; D006801:Humans; D007201:Indicator Dilution Techniques; D008168:Lung / Q000378:metabolism*; D008297:Male; D008875:Middle Aged; D010100:Oxygen / Q000097:blood; D011650:Pulmonary Alveoli / Q000378:metabolism; D012128:Respiratory Distress Syndrome / Q000378:metabolism* / Q000401:mortality / Q000503:physiopathology; D014508:Urea / Q000378:metabolism
chemical_list: D002250:Carbon Radioisotopes; D014508:Urea; D010100:Oxygen