Histopathological correlation with P/F ratios during ARDS in an ovine model treated with extracorporeal arteriovenous carbon dioxide removal (AVCO2R)

R. Diba, Abida Haque, S. K. Alpard, D. J. Deyo, A. Bidani, J. B. Zwischenberger

Research output: Contribution to journalConference articlepeer-review


AVCO2R allows reductions in peak airway pressure, ventilator dependent days, and improves survival in our ovine smoke/burn injury (LD40) model of ARDS. The inflection point of physiologic improvement (PaO2/FiO2 > 200) occurs at 48 hours of AVCO2R treatment, 96 hours post-injury. In this study, we correlated the histopathology with P/F ratio improvements during treatment with AVCO2R. Adult Suffolk ewes (n=10) received a cotton smoke insufflation (36 breaths) and 40% TBSA III° cutaneous flame burn injury followed by volume-controlled mechanical ventilation. At 40-48 hours post-injury, sheep underwent cannulation of the carotid artery (10-12F) and jugular vein (14F) and were connected to a low-resistance membrane gas exchanger (AVCO2R). Sheep were euthanized 96 hours post-injury (48 hours AVCO2R) and lung samples (2-3/animal) were fixed with 10% formalin and stained with hematoxylin-eosin and MOVAT. Pathological findings were graded as absent = 0, minimal = 1, mild = 2, moderate = 3, or severe = 4. We compared lung weights, expressed as a wet:dry ratio, in sheep with no injury (n=4) and to those with smoke/burn injury treated with AVCO2R. Pulmonary histology after 48 hours of AVCO2R revealed changes consistent with acute ARDS including mild edema (2.06 ± 1.43), interstitial inflammation (1.39 ± 1.14), atelectasis (1.6 ± .98), minimal hyaline membrane formation, alveolar type II proliferation, and alveolar hemorrhage. No thrombi or fibrosis was observed. Wet:dry ratios showed no significant difference in lung weights between normal and AVCO2R. AVCO2R improves survival from smoke/burn induced ARDS without correllative changes in lung histology. However, normalized wet:dry ratios suggest that AVCO2R reduces fluid transudation to improve gas exchange and outcomes.

Original languageEnglish (US)
Number of pages1
JournalASAIO Journal
Issue number2
StatePublished - Jan 1 2000
Event46th Annual Conference and Exposition of ASAIO - New York, NY, USA
Duration: Jun 28 2000Jul 1 2000

ASJC Scopus subject areas

  • Biophysics
  • Bioengineering
  • Biomaterials
  • Biomedical Engineering


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