MORPHOMETRY OF PARENCHYMAL AND VASCULAR ALTERATIONS IN ARDS AFTER EXTRACORPOREAL CARBON-DIOXIDE REMOVAL THERAPY (ECCO2-R-THERAPY)

The lungs of 12 patients suffering from ARDS treated by ECCO2-R-therapy were examined. The thickness of the interlobular septa, area portions of honeycombing, bleeding and lung parenchyma with diffuse alveolar damage were assessed by semi-automatic image analysis. Medial thickness of the pulmonary arteries with an external radius ranging between 40-mu-m and 150-mu-m was assessed planimetrically. The area portion of honeycombing ranged from 0% to 66% (average: 28.8%, standard deviation: 17.0%). The thickness of interlobular septa was increased with values between 74.0-mu-m and 195.5-mu-m (average: 140.4-mu-m, standard deviation: 41.7-mu-m; normal controls: 72.0-mu-m +/- 19.5-mu-m). Parenchymal and vascular changes were closely related: Average medial thickness rose from nearly normal values (4.9 %) in cases with low area portions of honeycombing and bleeding to the double (11.1 %) of normal values in cases with area portions of honeycombing and bleeding > 40 %. We conclude that parenchymal changes due to shock and high inspiratory O2 concentration lead to changes of the pulmonary arterial hemodynamics which result in a quickly developing medial hypertrophy.