Exogenous Surfactant Attenuates Lung Injury From Gastric-Acid Aspiration During Ex Vivo Reconditioning in Pigs

Background Lung injury (LI) due to gastric-acid aspiration is associated with poor posttransplantation outcomes. We investigated the effects of ex vivo lung perfusion (EVLP) reconditioning and surfactant administration on LI due to gastric-acid aspiration. Methods Thirty piglets were allocated at random to five groups: the lungs were studied 24 hr after gastric juice-induced LI of the left lower lobe (LLL), LI followed by EVLP (4 hr), or LI followed by LLL surfactant lavage immediately before EVLP; sham animals were studied 24 hr after saline infusion alone or followed by EVLP. Gross anatomy, hemodynamics, and aerodynamics were evaluated; neutrophil and bacterial counts were determined in bronchoalveolar lavage (BAL) fluid and blood. LLLs were evaluated based on a semi-quantitative histologic score, apoptotic cell death (TUNEL), and inflammatory cytokine levels. Results The sham and sham-EVLP groups were not significantly different. Compared with sham, LI animals had irreversible atelectasis, higher lung infection rates (P<0.0001) and BAL neutrophil percentages (P<0.0001), lower PaO2 (P=0.0006), higher IL-1 (P=0.022) and IL-8 (P=0.006), higher apoptotic cell percentages (P=0.007), and worse histologic severity scores (P<0.0001). EVLP alone did not improve these findings. Adding surfactant before EVLP returned PaO2, pulmonary vascular resistance, and apoptotic-cell percentage to sham-EVLP values but only partially improved the histologic severity score. Conclusion Local surfactant infusion immediately before EVLP improved the function of donor lungs injured by gastric juice aspiration. This strategy may hold promise for decreasing the shortage of donor lungs.